update readme (#673)

* replace antlr module

* refactor version of antlr

.codecov.yml

@@ -0,0 +1,4 @@
+ignore:
+  - "doc"
+  - "example"
+  - "tools"

.github/workflows/codeql-analysis.yml

@@ -0,0 +1,67 @@
+# For most projects, this workflow file will not need changing; you simply need
+# to commit it to your repository.
+#
+# You may wish to alter this file to override the set of languages analyzed,
+# or to provide custom queries or build logic.
+#
+# ******** NOTE ********
+# We have attempted to detect the languages in your repository. Please check
+# the `language` matrix defined below to confirm you have the correct set of
+# supported CodeQL languages.
+#
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [ master ]
+  schedule:
+    - cron: '18 19 * * 6'
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'go' ]
+        # CodeQL supports [ 'cpp', 'csharp', 'go', 'java', 'javascript', 'python' ]
+        # Learn more:
+        # https://docs.github.com/en/free-pro-team@latest/github/finding-security-vulnerabilities-and-errors-in-your-code/configuring-code-scanning#changing-the-languages-that-are-analyzed
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+
+    # Initializes the CodeQL tools for scanning.
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@v1
+      with:
+        languages: ${{ matrix.language }}
+        # If you wish to specify custom queries, you can do so here or in a config file.
+        # By default, queries listed here will override any specified in a config file.
+        # Prefix the list here with "+" to use these queries and those in the config file.
+        # queries: ./path/to/local/query, your-org/your-repo/queries@main
+
+    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
+    # If this step fails, then you should remove it and run the build manually (see below)
+    - name: Autobuild
+      uses: github/codeql-action/autobuild@v1
+
+    # ℹ️ Command-line programs to run using the OS shell.
+    # 📚 https://git.io/JvXDl
+
+    # ✏️ If the Autobuild fails above, remove it and uncomment the following three lines
+    #    and modify them (or add more) to build your code if your project
+    #    uses a compiled language
+
+    #- run: |
+    #   make bootstrap
+    #   make release
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v1

.github/workflows/go.yml

@@ -7,7 +7,6 @@ on:
     branches: [ master ]
 
 jobs:
-
   build:
     name: Build
     runs-on: ubuntu-latest
@@ -27,4 +26,9 @@ jobs:
         go get -v -t -d ./...
 
     - name: Test
-      run: go test -v -race ./...
+      run: go test -race -coverprofile=coverage.txt -covermode=atomic ./...
+
+    - name: Codecov
+      uses: codecov/codecov-action@v1.0.6
+      with:
+        token: ${{secrets.CODECOV_TOKEN}}

.gitignore

@@ -4,6 +4,7 @@
 # Unignore all with extensions
 !*.*
 !**/Dockerfile
+!**/Makefile
 
 # Unignore all dirs
 !*/
@@ -12,7 +13,6 @@
 .idea
 **/.DS_Store
 **/logs
-!Makefile
 
 # gitlab ci
 .cache

.gitlab-ci.yml

@@ -1,18 +0,0 @@
-stages:
-- analysis
-
-variables:
-  GOPATH: '/runner-cache/zero'
-  GOCACHE: '/runner-cache/zero'
-  GOPROXY: 'https://goproxy.cn,direct'
-
-analysis:
-  stage: analysis
-  image: golang
-  script:
-    - go version && go env
-    - go test -short $(go list ./...) | grep -v "no test"
-  only:
-   - merge_requests
-  tags:
-    - common

.golangci.yml

@@ -1,36 +0,0 @@
-run:
-  #  concurrency: 6
-  timeout: 5m
-  skip-dirs:
-    - core
-    - doc
-    - example
-    - rest
-    - rpcx
-    - tools
-
-
-linters:
-  disable-all: true
-  enable:
-    - bodyclose
-    - deadcode
-    - errcheck
-    - gosimple
-    - govet
-    - ineffassign
-    - staticcheck
-    - structcheck
-    - typecheck
-    - unused
-    - varcheck
-#    - dupl
-
-
-linters-settings:
-
-issues:
-  exclude-rules:
-    - linters:
-        - staticcheck
-      text: 'SA1019: (baseresponse.BoolResponse|oldresponse.FormatBadRequestResponse|oldresponse.FormatResponse)|SA5008: unknown JSON option ("optional"|"default=|"range=|"options=)'

core/bloom/bloom.go

@@ -13,15 +13,13 @@ const (
 	// maps as k in the error rate table
 	maps      = 14
 	setScript = `
-local key = KEYS[1]
 for _, offset in ipairs(ARGV) do
-	redis.call("setbit", key, offset, 1)
+	redis.call("setbit", KEYS[1], offset, 1)
 end
 `
 	testScript = `
-local key = KEYS[1]
 for _, offset in ipairs(ARGV) do
-	if tonumber(redis.call("getbit", key, offset)) == 0 then
+	if tonumber(redis.call("getbit", KEYS[1], offset)) == 0 then
 		return false
 	end
 end
@@ -29,44 +27,43 @@ return true
 `
 )
 
+// ErrTooLargeOffset indicates the offset is too large in bitset.
 var ErrTooLargeOffset = errors.New("too large offset")
 
 type (
-	BitSetProvider interface {
+	// A Filter is a bloom filter.
+	Filter struct {
+		bits   uint
+		bitSet bitSetProvider
+	}
+
+	bitSetProvider interface {
 		check([]uint) (bool, error)
 		set([]uint) error
 	}
-
-	BloomFilter struct {
-		bits   uint
-		maps   uint
-		bitSet BitSetProvider
-	}
 )
 
-// New create a BloomFilter, store is the backed redis, key is the key for the bloom filter,
+// New create a Filter, store is the backed redis, key is the key for the bloom filter,
 // bits is how many bits will be used, maps is how many hashes for each addition.
 // best practices:
 // elements - means how many actual elements
 // when maps = 14, formula: 0.7*(bits/maps), bits = 20*elements, the error rate is 0.000067 < 1e-4
 // for detailed error rate table, see http://pages.cs.wisc.edu/~cao/papers/summary-cache/node8.html
-func New(store *redis.Redis, key string, bits uint) *BloomFilter {
+func New(store *redis.Redis, key string, bits uint) *Filter {
-	return &BloomFilter{
+	return &Filter{
 		bits:   bits,
 		bitSet: newRedisBitSet(store, key, bits),
 	}
 }
 
-func (f *BloomFilter) Add(data []byte) error {
+// Add adds data into f.
+func (f *Filter) Add(data []byte) error {
 	locations := f.getLocations(data)
-	err := f.bitSet.set(locations)
+	return f.bitSet.set(locations)
-	if err != nil {
-		return err
-	}
-	return nil
 }
 
-func (f *BloomFilter) Exists(data []byte) (bool, error) {
+// Exists checks if data is in f.
+func (f *Filter) Exists(data []byte) (bool, error) {
 	locations := f.getLocations(data)
 	isSet, err := f.bitSet.check(locations)
 	if err != nil {
@@ -79,7 +76,7 @@ func (f *BloomFilter) Exists(data []byte) (bool, error) {
 	return true, nil
 }
 
-func (f *BloomFilter) getLocations(data []byte) []uint {
+func (f *Filter) getLocations(data []byte) []uint {
 	locations := make([]uint, maps)
 	for i := uint(0); i < maps; i++ {
 		hashValue := hash.Hash(append(data, byte(i)))
@@ -130,11 +127,12 @@ func (r *redisBitSet) check(offsets []uint) (bool, error) {
 		return false, err
 	}
 
-	if exists, ok := resp.(int64); !ok {
+	exists, ok := resp.(int64)
+	if !ok {
 		return false, nil
-	} else {
-		return exists == 1, nil
 	}
+
+	return exists == 1, nil
 }
 
 func (r *redisBitSet) del() error {
@@ -155,7 +153,7 @@ func (r *redisBitSet) set(offsets []uint) error {
 	_, err = r.store.Eval(setScript, []string{r.key}, args)
 	if err == redis.Nil {
 		return nil
-	} else {
-		return err
 	}
+
+	return err
 }

core/bloom/bloom_test.go

@@ -3,19 +3,15 @@ package bloom
 import (
 	"testing"
 
-	"github.com/alicebob/miniredis"
 	"github.com/stretchr/testify/assert"
-	"github.com/tal-tech/go-zero/core/stores/redis"
+	"github.com/tal-tech/go-zero/core/stores/redis/redistest"
 )
 
 func TestRedisBitSet_New_Set_Test(t *testing.T) {
-	s, err := miniredis.Run()
+	store, clean, err := redistest.CreateRedis()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Error("Miniredis could not start")
+	defer clean()
-	}
-	defer s.Close()
 
-	store := redis.NewRedis(s.Addr(), redis.NodeType)
 	bitSet := newRedisBitSet(store, "test_key", 1024)
 	isSetBefore, err := bitSet.check([]uint{0})
 	if err != nil {
@@ -46,13 +42,10 @@ func TestRedisBitSet_New_Set_Test(t *testing.T) {
 }
 
 func TestRedisBitSet_Add(t *testing.T) {
-	s, err := miniredis.Run()
+	store, clean, err := redistest.CreateRedis()
-	if err != nil {
+	assert.Nil(t, err)
-		t.Error("Miniredis could not start")
+	defer clean()
-	}
-	defer s.Close()
 
-	store := redis.NewRedis(s.Addr(), redis.NodeType)
 	filter := New(store, "test_key", 64)
 	assert.Nil(t, filter.Add([]byte("hello")))
 	assert.Nil(t, filter.Add([]byte("world")))

core/breaker/breaker.go

@@ -5,17 +5,12 @@ import (
 	"fmt"
 	"strings"
 	"sync"
-	"time"
 
 	"github.com/tal-tech/go-zero/core/mathx"
 	"github.com/tal-tech/go-zero/core/proc"
 	"github.com/tal-tech/go-zero/core/stat"
 	"github.com/tal-tech/go-zero/core/stringx"
-)
+	"github.com/tal-tech/go-zero/core/timex"
-
-const (
-	StateClosed State = iota
-	StateOpen
 )
 
 const (
@@ -23,15 +18,16 @@ const (
 	timeFormat        = "15:04:05"
 )
 
-// ErrServiceUnavailable is returned when the CB state is open
+// ErrServiceUnavailable is returned when the Breaker state is open.
 var ErrServiceUnavailable = errors.New("circuit breaker is open")
 
 type (
-	State      = int32
+	// Acceptable is the func to check if the error can be accepted.
 	Acceptable func(err error) bool
 
+	// A Breaker represents a circuit breaker.
 	Breaker interface {
-		// Name returns the name of the netflixBreaker.
+		// Name returns the name of the Breaker.
 		Name() string
 
 		// Allow checks if the request is allowed.
@@ -40,37 +36,41 @@ type (
 		// If not allow, ErrServiceUnavailable will be returned.
 		Allow() (Promise, error)
 
-		// Do runs the given request if the netflixBreaker accepts it.
+		// Do runs the given request if the Breaker accepts it.
-		// Do returns an error instantly if the netflixBreaker rejects the request.
+		// Do returns an error instantly if the Breaker rejects the request.
-		// If a panic occurs in the request, the netflixBreaker handles it as an error
+		// If a panic occurs in the request, the Breaker handles it as an error
 		// and causes the same panic again.
 		Do(req func() error) error
 
-		// DoWithAcceptable runs the given request if the netflixBreaker accepts it.
+		// DoWithAcceptable runs the given request if the Breaker accepts it.
-		// Do returns an error instantly if the netflixBreaker rejects the request.
+		// DoWithAcceptable returns an error instantly if the Breaker rejects the request.
-		// If a panic occurs in the request, the netflixBreaker handles it as an error
+		// If a panic occurs in the request, the Breaker handles it as an error
 		// and causes the same panic again.
 		// acceptable checks if it's a successful call, even if the err is not nil.
 		DoWithAcceptable(req func() error, acceptable Acceptable) error
 
-		// DoWithFallback runs the given request if the netflixBreaker accepts it.
+		// DoWithFallback runs the given request if the Breaker accepts it.
-		// DoWithFallback runs the fallback if the netflixBreaker rejects the request.
+		// DoWithFallback runs the fallback if the Breaker rejects the request.
-		// If a panic occurs in the request, the netflixBreaker handles it as an error
+		// If a panic occurs in the request, the Breaker handles it as an error
 		// and causes the same panic again.
 		DoWithFallback(req func() error, fallback func(err error) error) error
 
-		// DoWithFallbackAcceptable runs the given request if the netflixBreaker accepts it.
+		// DoWithFallbackAcceptable runs the given request if the Breaker accepts it.
-		// DoWithFallback runs the fallback if the netflixBreaker rejects the request.
+		// DoWithFallbackAcceptable runs the fallback if the Breaker rejects the request.
-		// If a panic occurs in the request, the netflixBreaker handles it as an error
+		// If a panic occurs in the request, the Breaker handles it as an error
 		// and causes the same panic again.
 		// acceptable checks if it's a successful call, even if the err is not nil.
 		DoWithFallbackAcceptable(req func() error, fallback func(err error) error, acceptable Acceptable) error
 	}
 
-	BreakerOption func(breaker *circuitBreaker)
+	// Option defines the method to customize a Breaker.
+	Option func(breaker *circuitBreaker)
 
+	// Promise interface defines the callbacks that returned by Breaker.Allow.
 	Promise interface {
+		// Accept tells the Breaker that the call is successful.
 		Accept()
+		// Reject tells the Breaker that the call is failed.
 		Reject(reason string)
 	}
 
@@ -95,7 +95,9 @@ type (
 	}
 )
 
-func NewBreaker(opts ...BreakerOption) Breaker {
+// NewBreaker returns a Breaker object.
+// opts can be used to customize the Breaker.
+func NewBreaker(opts ...Option) Breaker {
 	var b circuitBreaker
 	for _, opt := range opts {
 		opt(&b)
@@ -133,7 +135,8 @@ func (cb *circuitBreaker) Name() string {
 	return cb.name
 }
 
-func WithName(name string) BreakerOption {
+// WithName returns a function to set the name of a Breaker.
+func WithName(name string) Option {
 	return func(b *circuitBreaker) {
 		b.name = name
 	}
@@ -195,23 +198,23 @@ type errorWindow struct {
 
 func (ew *errorWindow) add(reason string) {
 	ew.lock.Lock()
-	ew.reasons[ew.index] = fmt.Sprintf("%s %s", time.Now().Format(timeFormat), reason)
+	ew.reasons[ew.index] = fmt.Sprintf("%s %s", timex.Time().Format(timeFormat), reason)
 	ew.index = (ew.index + 1) % numHistoryReasons
 	ew.count = mathx.MinInt(ew.count+1, numHistoryReasons)
 	ew.lock.Unlock()
 }
 
 func (ew *errorWindow) String() string {
-	var builder strings.Builder
+	var reasons []string
 
 	ew.lock.Lock()
-	for i := ew.index + ew.count - 1; i >= ew.index; i-- {
+	// reverse order
-		builder.WriteString(ew.reasons[i%numHistoryReasons])
+	for i := ew.index - 1; i >= ew.index-ew.count; i-- {
-		builder.WriteByte('\n')
+		reasons = append(reasons, ew.reasons[(i+numHistoryReasons)%numHistoryReasons])
 	}
 	ew.lock.Unlock()
 
-	return builder.String()
+	return strings.Join(reasons, "\n")
 }
 
 type promiseWithReason struct {

core/breaker/breaker_test.go

@@ -2,7 +2,9 @@ package breaker
 
 import (
 	"errors"
+	"fmt"
 	"strconv"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -33,6 +35,84 @@ func TestLogReason(t *testing.T) {
 	assert.Equal(t, numHistoryReasons, errs.count)
 }
 
+func TestErrorWindow(t *testing.T) {
+	tests := []struct {
+		name    string
+		reasons []string
+	}{
+		{
+			name: "no error",
+		},
+		{
+			name:    "one error",
+			reasons: []string{"foo"},
+		},
+		{
+			name:    "two errors",
+			reasons: []string{"foo", "bar"},
+		},
+		{
+			name:    "five errors",
+			reasons: []string{"first", "second", "third", "fourth", "fifth"},
+		},
+		{
+			name:    "six errors",
+			reasons: []string{"first", "second", "third", "fourth", "fifth", "sixth"},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			var ew errorWindow
+			for _, reason := range test.reasons {
+				ew.add(reason)
+			}
+			var reasons []string
+			if len(test.reasons) > numHistoryReasons {
+				reasons = test.reasons[len(test.reasons)-numHistoryReasons:]
+			} else {
+				reasons = test.reasons
+			}
+			for _, reason := range reasons {
+				assert.True(t, strings.Contains(ew.String(), reason), fmt.Sprintf("actual: %s", ew.String()))
+			}
+		})
+	}
+}
+
+func TestPromiseWithReason(t *testing.T) {
+	tests := []struct {
+		name   string
+		reason string
+		expect string
+	}{
+		{
+			name: "success",
+		},
+		{
+			name:   "success",
+			reason: "fail",
+			expect: "fail",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			promise := promiseWithReason{
+				promise: new(mockedPromise),
+				errWin:  new(errorWindow),
+			}
+			if len(test.reason) == 0 {
+				promise.Accept()
+			} else {
+				promise.Reject(test.reason)
+			}
+
+			assert.True(t, strings.Contains(promise.errWin.String(), test.expect))
+		})
+	}
+}
+
 func BenchmarkGoogleBreaker(b *testing.B) {
 	br := NewBreaker()
 	for i := 0; i < b.N; i++ {
@@ -41,3 +121,11 @@ func BenchmarkGoogleBreaker(b *testing.B) {
 		})
 	}
 }
+
+type mockedPromise struct{}
+
+func (m *mockedPromise) Accept() {
+}
+
+func (m *mockedPromise) Reject() {
+}

core/breaker/breakers.go

@@ -7,24 +7,28 @@ var (
 	breakers = make(map[string]Breaker)
 )
 
+// Do calls Breaker.Do on the Breaker with given name.
 func Do(name string, req func() error) error {
 	return do(name, func(b Breaker) error {
 		return b.Do(req)
 	})
 }
 
+// DoWithAcceptable calls Breaker.DoWithAcceptable on the Breaker with given name.
 func DoWithAcceptable(name string, req func() error, acceptable Acceptable) error {
 	return do(name, func(b Breaker) error {
 		return b.DoWithAcceptable(req, acceptable)
 	})
 }
 
+// DoWithFallback calls Breaker.DoWithFallback on the Breaker with given name.
 func DoWithFallback(name string, req func() error, fallback func(err error) error) error {
 	return do(name, func(b Breaker) error {
 		return b.DoWithFallback(req, fallback)
 	})
 }
 
+// DoWithFallbackAcceptable calls Breaker.DoWithFallbackAcceptable on the Breaker with given name.
 func DoWithFallbackAcceptable(name string, req func() error, fallback func(err error) error,
 	acceptable Acceptable) error {
 	return do(name, func(b Breaker) error {
@@ -32,6 +36,7 @@ func DoWithFallbackAcceptable(name string, req func() error, fallback func(err e
 	})
 }
 
+// GetBreaker returns the Breaker with the given name.
 func GetBreaker(name string) Breaker {
 	lock.RLock()
 	b, ok := breakers[name]
@@ -41,36 +46,23 @@ func GetBreaker(name string) Breaker {
 	}
 
 	lock.Lock()
-	defer lock.Unlock()
+	b, ok = breakers[name]
+	if !ok {
+		b = NewBreaker(WithName(name))
+		breakers[name] = b
+	}
+	lock.Unlock()
 
-	b = NewBreaker()
-	breakers[name] = b
 	return b
 }
 
-func NoBreakFor(name string) {
+// NoBreakerFor disables the circuit breaker for the given name.
+func NoBreakerFor(name string) {
 	lock.Lock()
 	breakers[name] = newNoOpBreaker()
 	lock.Unlock()
 }
 
 func do(name string, execute func(b Breaker) error) error {
-	lock.RLock()
+	return execute(GetBreaker(name))
-	b, ok := breakers[name]
-	lock.RUnlock()
-	if ok {
-		return execute(b)
-	} else {
-		lock.Lock()
-		b, ok = breakers[name]
-		if ok {
-			lock.Unlock()
-			return execute(b)
-		} else {
-			b = NewBreaker(WithName(name))
-			breakers[name] = b
-			lock.Unlock()
-			return execute(b)
-		}
-	}
 }

core/breaker/breakers_test.go

@@ -55,7 +55,7 @@ func TestBreakersDoWithAcceptable(t *testing.T) {
 }
 
 func TestBreakersNoBreakerFor(t *testing.T) {
-	NoBreakFor("any")
+	NoBreakerFor("any")
 	errDummy := errors.New("any")
 	for i := 0; i < 10000; i++ {
 		assert.Equal(t, errDummy, GetBreaker("any").Do(func() error {

core/breaker/googlebreaker.go

@@ -2,7 +2,6 @@ package breaker
 
 import (
 	"math"
-	"sync/atomic"
 	"time"
 
 	"github.com/tal-tech/go-zero/core/collection"
@@ -21,7 +20,6 @@ const (
 // see Client-Side Throttling section in https://landing.google.com/sre/sre-book/chapters/handling-overload/
 type googleBreaker struct {
 	k     float64
-	state int32
 	stat  *collection.RollingWindow
 	proba *mathx.Proba
 }
@@ -32,7 +30,6 @@ func newGoogleBreaker() *googleBreaker {
 	return &googleBreaker{
 		stat:  st,
 		k:     k,
-		state: StateClosed,
 		proba: mathx.NewProba(),
 	}
 }
@@ -43,15 +40,9 @@ func (b *googleBreaker) accept() error {
 	// https://landing.google.com/sre/sre-book/chapters/handling-overload/#eq2101
 	dropRatio := math.Max(0, (float64(total-protection)-weightedAccepts)/float64(total+1))
 	if dropRatio <= 0 {
-		if atomic.LoadInt32(&b.state) == StateOpen {
-			atomic.CompareAndSwapInt32(&b.state, StateOpen, StateClosed)
-		}
 		return nil
 	}
 
-	if atomic.LoadInt32(&b.state) == StateClosed {
-		atomic.CompareAndSwapInt32(&b.state, StateClosed, StateOpen)
-	}
 	if b.proba.TrueOnProba(dropRatio) {
 		return ErrServiceUnavailable
 	}
@@ -73,9 +64,9 @@ func (b *googleBreaker) doReq(req func() error, fallback func(err error) error,
 	if err := b.accept(); err != nil {
 		if fallback != nil {
 			return fallback(err)
-		} else {
-			return err
 		}
+
+		return err
 	}
 
 	defer func() {

core/breaker/googlebreaker_test.go

@@ -2,7 +2,6 @@ package breaker
 
 import (
 	"errors"
-	"math"
 	"math/rand"
 	"testing"
 	"time"
@@ -27,7 +26,6 @@ func getGoogleBreaker() *googleBreaker {
 	return &googleBreaker{
 		stat:  st,
 		k:     5,
-		state: StateClosed,
 		proba: mathx.NewProba(),
 	}
 }
@@ -158,7 +156,7 @@ func TestGoogleBreakerSelfProtection(t *testing.T) {
 	t.Run("total request > 100, total < 2 * success", func(t *testing.T) {
 		b := getGoogleBreaker()
 		size := rand.Intn(10000)
-		accepts := int(math.Ceil(float64(size))) + 1
+		accepts := size + 1
 		markSuccess(b, accepts)
 		markFailed(b, size-accepts)
 		assert.Nil(t, b.accept())

core/cmdline/input.go

@@ -7,11 +7,13 @@ import (
 	"strings"
 )
 
+// EnterToContinue let stdin waiting for an enter key to continue.
 func EnterToContinue() {
 	fmt.Print("Press 'Enter' to continue...")
 	bufio.NewReader(os.Stdin).ReadBytes('\n')
 }
 
+// ReadLine shows prompt to stdout and read a line from stdin.
 func ReadLine(prompt string) string {
 	fmt.Print(prompt)
 	input, _ := bufio.NewReader(os.Stdin).ReadString('\n')

core/cmdline/input_test.go

@@ -0,0 +1,80 @@
+package cmdline
+
+import (
+	"fmt"
+	"os"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/tal-tech/go-zero/core/iox"
+	"github.com/tal-tech/go-zero/core/lang"
+)
+
+func TestEnterToContinue(t *testing.T) {
+	restore, err := iox.RedirectInOut()
+	assert.Nil(t, err)
+	defer restore()
+
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		defer wg.Done()
+		fmt.Println()
+	}()
+	go func() {
+		defer wg.Done()
+		EnterToContinue()
+	}()
+
+	wait := make(chan lang.PlaceholderType)
+	go func() {
+		wg.Wait()
+		close(wait)
+	}()
+
+	select {
+	case <-time.After(time.Second):
+		t.Error("timeout")
+	case <-wait:
+	}
+}
+
+func TestReadLine(t *testing.T) {
+	r, w, err := os.Pipe()
+	assert.Nil(t, err)
+	ow := os.Stdout
+	os.Stdout = w
+	or := os.Stdin
+	os.Stdin = r
+	defer func() {
+		os.Stdin = or
+		os.Stdout = ow
+	}()
+
+	const message = "hello"
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		defer wg.Done()
+		fmt.Println(message)
+	}()
+	go func() {
+		defer wg.Done()
+		input := ReadLine("")
+		assert.Equal(t, message, input)
+	}()
+
+	wait := make(chan lang.PlaceholderType)
+	go func() {
+		wg.Wait()
+		close(wait)
+	}()
+
+	select {
+	case <-time.After(time.Second):
+		t.Error("timeout")
+	case <-wait:
+	}
+}

core/codec/aesecb.go

@@ -10,6 +10,7 @@ import (
 	"github.com/tal-tech/go-zero/core/logx"
 )
 
+// ErrPaddingSize indicates bad padding size.
 var ErrPaddingSize = errors.New("padding size error")
 
 type ecb struct {
@@ -26,6 +27,7 @@ func newECB(b cipher.Block) *ecb {
 
 type ecbEncrypter ecb
 
+// NewECBEncrypter returns an ECB encrypter.
 func NewECBEncrypter(b cipher.Block) cipher.BlockMode {
 	return (*ecbEncrypter)(newECB(b))
 }
@@ -52,6 +54,7 @@ func (x *ecbEncrypter) CryptBlocks(dst, src []byte) {
 
 type ecbDecrypter ecb
 
+// NewECBDecrypter returns an ECB decrypter.
 func NewECBDecrypter(b cipher.Block) cipher.BlockMode {
 	return (*ecbDecrypter)(newECB(b))
 }
@@ -78,6 +81,7 @@ func (x *ecbDecrypter) CryptBlocks(dst, src []byte) {
 	}
 }
 
+// EcbDecrypt decrypts src with the given key.
 func EcbDecrypt(key, src []byte) ([]byte, error) {
 	block, err := aes.NewCipher(key)
 	if err != nil {
@@ -92,6 +96,8 @@ func EcbDecrypt(key, src []byte) ([]byte, error) {
 	return pkcs5Unpadding(decrypted, decrypter.BlockSize())
 }
 
+// EcbDecryptBase64 decrypts base64 encoded src with the given base64 encoded key.
+// The returned string is also base64 encoded.
 func EcbDecryptBase64(key, src string) (string, error) {
 	keyBytes, err := getKeyBytes(key)
 	if err != nil {
@@ -111,6 +117,7 @@ func EcbDecryptBase64(key, src string) (string, error) {
 	return base64.StdEncoding.EncodeToString(decryptedBytes), nil
 }
 
+// EcbEncrypt encrypts src with the given key.
 func EcbEncrypt(key, src []byte) ([]byte, error) {
 	block, err := aes.NewCipher(key)
 	if err != nil {
@@ -126,6 +133,8 @@ func EcbEncrypt(key, src []byte) ([]byte, error) {
 	return crypted, nil
 }
 
+// EcbEncryptBase64 encrypts base64 encoded src with the given base64 encoded key.
+// The returned string is also base64 encoded.
 func EcbEncryptBase64(key, src string) (string, error) {
 	keyBytes, err := getKeyBytes(key)
 	if err != nil {
@@ -146,15 +155,16 @@ func EcbEncryptBase64(key, src string) (string, error) {
 }
 
 func getKeyBytes(key string) ([]byte, error) {
-	if len(key) > 32 {
+	if len(key) <= 32 {
-		if keyBytes, err := base64.StdEncoding.DecodeString(key); err != nil {
+		return []byte(key), nil
-			return nil, err
-		} else {
-			return keyBytes, nil
-		}
 	}
 
-	return []byte(key), nil
+	keyBytes, err := base64.StdEncoding.DecodeString(key)
+	if err != nil {
+		return nil, err
+	}
+
+	return keyBytes, nil
 }
 
 func pkcs5Padding(ciphertext []byte, blockSize int) []byte {

core/codec/aesecb_test.go

@@ -0,0 +1,65 @@
+package codec
+
+import (
+	"encoding/base64"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAesEcb(t *testing.T) {
+	var (
+		key     = []byte("q4t7w!z%C*F-JaNdRgUjXn2r5u8x/A?D")
+		val     = []byte("hello")
+		badKey1 = []byte("aaaaaaaaa")
+		// more than 32 chars
+		badKey2 = []byte("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
+	)
+	_, err := EcbEncrypt(badKey1, val)
+	assert.NotNil(t, err)
+	_, err = EcbEncrypt(badKey2, val)
+	assert.NotNil(t, err)
+	dst, err := EcbEncrypt(key, val)
+	assert.Nil(t, err)
+	_, err = EcbDecrypt(badKey1, dst)
+	assert.NotNil(t, err)
+	_, err = EcbDecrypt(badKey2, dst)
+	assert.NotNil(t, err)
+	_, err = EcbDecrypt(key, val)
+	// not enough block, just nil
+	assert.Nil(t, err)
+	src, err := EcbDecrypt(key, dst)
+	assert.Nil(t, err)
+	assert.Equal(t, val, src)
+}
+
+func TestAesEcbBase64(t *testing.T) {
+	const (
+		val     = "hello"
+		badKey1 = "aaaaaaaaa"
+		// more than 32 chars
+		badKey2 = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+	)
+	key := []byte("q4t7w!z%C*F-JaNdRgUjXn2r5u8x/A?D")
+	b64Key := base64.StdEncoding.EncodeToString(key)
+	b64Val := base64.StdEncoding.EncodeToString([]byte(val))
+	_, err := EcbEncryptBase64(badKey1, val)
+	assert.NotNil(t, err)
+	_, err = EcbEncryptBase64(badKey2, val)
+	assert.NotNil(t, err)
+	_, err = EcbEncryptBase64(b64Key, val)
+	assert.NotNil(t, err)
+	dst, err := EcbEncryptBase64(b64Key, b64Val)
+	assert.Nil(t, err)
+	_, err = EcbDecryptBase64(badKey1, dst)
+	assert.NotNil(t, err)
+	_, err = EcbDecryptBase64(badKey2, dst)
+	assert.NotNil(t, err)
+	_, err = EcbDecryptBase64(b64Key, val)
+	assert.NotNil(t, err)
+	src, err := EcbDecryptBase64(b64Key, dst)
+	assert.Nil(t, err)
+	b, err := base64.StdEncoding.DecodeString(src)
+	assert.Nil(t, err)
+	assert.Equal(t, val, string(b))
+}

core/codec/dh.go

@@ -11,8 +11,11 @@ import (
 // 2048-bit MODP Group
 
 var (
-	ErrInvalidPriKey    = errors.New("invalid private key")
+	// ErrInvalidPriKey indicates the invalid private key.
-	ErrInvalidPubKey    = errors.New("invalid public key")
+	ErrInvalidPriKey = errors.New("invalid private key")
+	// ErrInvalidPubKey indicates the invalid public key.
+	ErrInvalidPubKey = errors.New("invalid public key")
+	// ErrPubKeyOutOfBound indicates the public key is out of bound.
 	ErrPubKeyOutOfBound = errors.New("public key out of bound")
 
 	p, _ = new(big.Int).SetString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
@@ -20,11 +23,13 @@ var (
 	zero = big.NewInt(0)
 )
 
+// DhKey defines the Diffie Hellman key.
 type DhKey struct {
 	PriKey *big.Int
 	PubKey *big.Int
 }
 
+// ComputeKey returns a key from public key and private key.
 func ComputeKey(pubKey, priKey *big.Int) (*big.Int, error) {
 	if pubKey == nil {
 		return nil, ErrInvalidPubKey
@@ -41,6 +46,7 @@ func ComputeKey(pubKey, priKey *big.Int) (*big.Int, error) {
 	return new(big.Int).Exp(pubKey, priKey, p), nil
 }
 
+// GenerateKey returns a Diffie Hellman key.
 func GenerateKey() (*DhKey, error) {
 	var err error
 	var x *big.Int
@@ -63,10 +69,12 @@ func GenerateKey() (*DhKey, error) {
 	return key, nil
 }
 
+// NewPublicKey returns a public key from the given bytes.
 func NewPublicKey(bs []byte) *big.Int {
 	return new(big.Int).SetBytes(bs)
 }
 
+// Bytes returns public key bytes.
 func (k *DhKey) Bytes() []byte {
 	if k.PubKey == nil {
 		return nil

core/codec/dh_test.go

@@ -71,3 +71,12 @@ func TestDiffieHellmanMiddleManAttack(t *testing.T) {
 	assert.Nil(t, err)
 	assert.Equal(t, string(src), string(decryptedSrc))
 }
+
+func TestKeyBytes(t *testing.T) {
+	var empty DhKey
+	assert.Equal(t, 0, len(empty.Bytes()))
+
+	key, err := GenerateKey()
+	assert.Nil(t, err)
+	assert.True(t, len(key.Bytes()) > 0)
+}

core/codec/gzip.go

@@ -6,6 +6,9 @@ import (
 	"io"
 )
 
+const unzipLimit = 100 * 1024 * 1024 // 100MB
+
+// Gzip compresses bs.
 func Gzip(bs []byte) []byte {
 	var b bytes.Buffer
 
@@ -16,6 +19,7 @@ func Gzip(bs []byte) []byte {
 	return b.Bytes()
 }
 
+// Gunzip uncompresses bs.
 func Gunzip(bs []byte) ([]byte, error) {
 	r, err := gzip.NewReader(bytes.NewBuffer(bs))
 	if err != nil {
@@ -24,8 +28,7 @@ func Gunzip(bs []byte) ([]byte, error) {
 	defer r.Close()
 
 	var c bytes.Buffer
-	_, err = io.Copy(&c, r)
+	if _, err = io.Copy(&c, io.LimitReader(r, unzipLimit)); err != nil {
-	if err != nil {
 		return nil, err
 	}
 

core/codec/hmac.go

@@ -7,12 +7,14 @@ import (
 	"io"
 )
 
+// Hmac returns HMAC bytes for body with the given key.
 func Hmac(key []byte, body string) []byte {
 	h := hmac.New(sha256.New, key)
 	io.WriteString(h, body)
 	return h.Sum(nil)
 }
 
+// HmacBase64 returns the base64 encoded string of HMAC for body with the given key.
 func HmacBase64(key []byte, body string) string {
 	return base64.StdEncoding.EncodeToString(Hmac(key, body))
 }

core/codec/hmac_test.go

@@ -0,0 +1,19 @@
+package codec
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestHmac(t *testing.T) {
+	ret := Hmac([]byte("foo"), "bar")
+	assert.Equal(t, "f9320baf0249169e73850cd6156ded0106e2bb6ad8cab01b7bbbebe6d1065317",
+		fmt.Sprintf("%x", ret))
+}
+
+func TestHmacBase64(t *testing.T) {
+	ret := HmacBase64([]byte("foo"), "bar")
+	assert.Equal(t, "+TILrwJJFp5zhQzWFW3tAQbiu2rYyrAbe7vr5tEGUxc=", ret)
+}

core/codec/rsa.go

@@ -11,17 +11,22 @@ import (
 )
 
 var (
+	// ErrPrivateKey indicates the invalid private key.
 	ErrPrivateKey = errors.New("private key error")
-	ErrPublicKey  = errors.New("failed to parse PEM block containing the public key")
+	// ErrPublicKey indicates the invalid public key.
-	ErrNotRsaKey  = errors.New("key type is not RSA")
+	ErrPublicKey = errors.New("failed to parse PEM block containing the public key")
+	// ErrNotRsaKey indicates the invalid RSA key.
+	ErrNotRsaKey = errors.New("key type is not RSA")
 )
 
 type (
+	// RsaDecrypter represents a RSA decrypter.
 	RsaDecrypter interface {
 		Decrypt(input []byte) ([]byte, error)
 		DecryptBase64(input string) ([]byte, error)
 	}
 
+	// RsaEncrypter represents a RSA encrypter.
 	RsaEncrypter interface {
 		Encrypt(input []byte) ([]byte, error)
 	}
@@ -41,6 +46,7 @@ type (
 	}
 )
 
+// NewRsaDecrypter returns a RsaDecrypter with the given file.
 func NewRsaDecrypter(file string) (RsaDecrypter, error) {
 	content, err := ioutil.ReadFile(file)
 	if err != nil {
@@ -84,6 +90,7 @@ func (r *rsaDecrypter) DecryptBase64(input string) ([]byte, error) {
 	return r.Decrypt(base64Decoded)
 }
 
+// NewRsaEncrypter returns a RsaEncrypter with the given key.
 func NewRsaEncrypter(key []byte) (RsaEncrypter, error) {
 	block, _ := pem.Decode(key)
 	if block == nil {

core/codec/rsa_test.go

@@ -0,0 +1,58 @@
+package codec
+
+import (
+	"encoding/base64"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/tal-tech/go-zero/core/fs"
+)
+
+const (
+	priKey = `-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----`
+	pubKey = `-----BEGIN PUBLIC KEY-----
+MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC4TJk3onpqb2RYE3wwt23J9SHL
+FstHGSkUYFLe+nl1dEKHbD+/Zt95L757J3xGTrwoTc7KCTxbrgn+stn0w52BNjj/
+kIE2ko4lbh/v8Fl14AyVR9msfKtKOnhe5FCT72mdtApr+qvzcC3q9hfXwkyQU32p
+v7q5UimZ205iKSBmgQIDAQAB
+-----END PUBLIC KEY-----`
+	testBody = `this is the content`
+)
+
+func TestCryption(t *testing.T) {
+	enc, err := NewRsaEncrypter([]byte(pubKey))
+	assert.Nil(t, err)
+	ret, err := enc.Encrypt([]byte(testBody))
+	assert.Nil(t, err)
+
+	file, err := fs.TempFilenameWithText(priKey)
+	assert.Nil(t, err)
+	dec, err := NewRsaDecrypter(file)
+	assert.Nil(t, err)
+	actual, err := dec.Decrypt(ret)
+	assert.Nil(t, err)
+	assert.Equal(t, testBody, string(actual))
+
+	actual, err = dec.DecryptBase64(base64.StdEncoding.EncodeToString(ret))
+	assert.Nil(t, err)
+	assert.Equal(t, testBody, string(actual))
+}
+
+func TestBadPubKey(t *testing.T) {
+	_, err := NewRsaEncrypter([]byte("foo"))
+	assert.Equal(t, ErrPublicKey, err)
+}

core/collection/cache.go

@@ -23,13 +23,14 @@ const (
 var emptyLruCache = emptyLru{}
 
 type (
+	// CacheOption defines the method to customize a Cache.
 	CacheOption func(cache *Cache)
 
+	// A Cache object is a in-memory cache.
 	Cache struct {
 		name           string
 		lock           sync.Mutex
 		data           map[string]interface{}
-		evicts         *list.List
 		expire         time.Duration
 		timingWheel    *TimingWheel
 		lruCache       lru
@@ -39,6 +40,7 @@ type (
 	}
 )
 
+// NewCache returns a Cache with given expire.
 func NewCache(expire time.Duration, opts ...CacheOption) (*Cache, error) {
 	cache := &Cache{
 		data:           make(map[string]interface{}),
@@ -73,6 +75,7 @@ func NewCache(expire time.Duration, opts ...CacheOption) (*Cache, error) {
 	return cache, nil
 }
 
+// Del deletes the item with the given key from c.
 func (c *Cache) Del(key string) {
 	c.lock.Lock()
 	delete(c.data, key)
@@ -81,13 +84,9 @@ func (c *Cache) Del(key string) {
 	c.timingWheel.RemoveTimer(key)
 }
 
+// Get returns the item with the given key from c.
 func (c *Cache) Get(key string) (interface{}, bool) {
-	c.lock.Lock()
+	value, ok := c.doGet(key)
-	value, ok := c.data[key]
-	if ok {
-		c.lruCache.add(key)
-	}
-	c.lock.Unlock()
 	if ok {
 		c.stats.IncrementHit()
 	} else {
@@ -97,6 +96,7 @@ func (c *Cache) Get(key string) (interface{}, bool) {
 	return value, ok
 }
 
+// Set sets value into c with key.
 func (c *Cache) Set(key string, value interface{}) {
 	c.lock.Lock()
 	_, ok := c.data[key]
@@ -112,13 +112,29 @@ func (c *Cache) Set(key string, value interface{}) {
 	}
 }
 
+// Take returns the item with the given key.
+// If the item is in c, return it directly.
+// If not, use fetch method to get the item, set into c and return it.
 func (c *Cache) Take(key string, fetch func() (interface{}, error)) (interface{}, error) {
-	val, fresh, err := c.barrier.DoEx(key, func() (interface{}, error) {
+	if val, ok := c.doGet(key); ok {
+		c.stats.IncrementHit()
+		return val, nil
+	}
+
+	var fresh bool
+	val, err := c.barrier.Do(key, func() (interface{}, error) {
+		// because O(1) on map search in memory, and fetch is an IO query
+		// so we do double check, cache might be taken by another call
+		if val, ok := c.doGet(key); ok {
+			return val, nil
+		}
+
 		v, e := fetch()
 		if e != nil {
 			return nil, e
 		}
 
+		fresh = true
 		c.Set(key, v)
 		return v, nil
 	})
@@ -129,14 +145,25 @@ func (c *Cache) Take(key string, fetch func() (interface{}, error)) (interface{}
 	if fresh {
 		c.stats.IncrementMiss()
 		return val, nil
-	} else {
-		// got the result from previous ongoing query
-		c.stats.IncrementHit()
 	}
 
+	// got the result from previous ongoing query
+	c.stats.IncrementHit()
 	return val, nil
 }
 
+func (c *Cache) doGet(key string) (interface{}, bool) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	value, ok := c.data[key]
+	if ok {
+		c.lruCache.add(key)
+	}
+
+	return value, ok
+}
+
 func (c *Cache) onEvict(key string) {
 	// already locked
 	delete(c.data, key)
@@ -149,6 +176,7 @@ func (c *Cache) size() int {
 	return len(c.data)
 }
 
+// WithLimit customizes a Cache with items up to limit.
 func WithLimit(limit int) CacheOption {
 	return func(cache *Cache) {
 		if limit > 0 {
@@ -157,6 +185,7 @@ func WithLimit(limit int) CacheOption {
 	}
 }
 
+// WithName customizes a Cache with the given name.
 func WithName(name string) CacheOption {
 	return func(cache *Cache) {
 		cache.name = name
@@ -258,18 +287,15 @@ func (cs *cacheStat) statLoop() {
 	ticker := time.NewTicker(statInterval)
 	defer ticker.Stop()
 
-	for {
+	for range ticker.C {
-		select {
+		hit := atomic.SwapUint64(&cs.hit, 0)
-		case <-ticker.C:
+		miss := atomic.SwapUint64(&cs.miss, 0)
-			hit := atomic.SwapUint64(&cs.hit, 0)
+		total := hit + miss
-			miss := atomic.SwapUint64(&cs.miss, 0)
+		if total == 0 {
-			total := hit + miss
+			continue
-			if total == 0 {
-				continue
-			}
-			percent := 100 * float32(hit) / float32(total)
-			logx.Statf("cache(%s) - qpm: %d, hit_ratio: %.1f%%, elements: %d, hit: %d, miss: %d",
-				cs.name, total, percent, cs.sizeCallback(), hit, miss)
 		}
+		percent := 100 * float32(hit) / float32(total)
+		logx.Statf("cache(%s) - qpm: %d, hit_ratio: %.1f%%, elements: %d, hit: %d, miss: %d",
+			cs.name, total, percent, cs.sizeCallback(), hit, miss)
 	}
 }

core/collection/cache_test.go

@@ -1,6 +1,7 @@
 package collection
 
 import (
+	"errors"
 	"strconv"
 	"sync"
 	"sync/atomic"
@@ -10,6 +11,8 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+var errDummy = errors.New("dummy")
+
 func TestCacheSet(t *testing.T) {
 	cache, err := NewCache(time.Second*2, WithName("any"))
 	assert.Nil(t, err)
@@ -63,6 +66,54 @@ func TestCacheTake(t *testing.T) {
 	assert.Equal(t, int32(1), atomic.LoadInt32(&count))
 }
 
+func TestCacheTakeExists(t *testing.T) {
+	cache, err := NewCache(time.Second * 2)
+	assert.Nil(t, err)
+
+	var count int32
+	var wg sync.WaitGroup
+	for i := 0; i < 100; i++ {
+		wg.Add(1)
+		go func() {
+			cache.Set("first", "first element")
+			cache.Take("first", func() (interface{}, error) {
+				atomic.AddInt32(&count, 1)
+				time.Sleep(time.Millisecond * 100)
+				return "first element", nil
+			})
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+
+	assert.Equal(t, 1, cache.size())
+	assert.Equal(t, int32(0), atomic.LoadInt32(&count))
+}
+
+func TestCacheTakeError(t *testing.T) {
+	cache, err := NewCache(time.Second * 2)
+	assert.Nil(t, err)
+
+	var count int32
+	var wg sync.WaitGroup
+	for i := 0; i < 100; i++ {
+		wg.Add(1)
+		go func() {
+			_, err := cache.Take("first", func() (interface{}, error) {
+				atomic.AddInt32(&count, 1)
+				time.Sleep(time.Millisecond * 100)
+				return "", errDummy
+			})
+			assert.Equal(t, errDummy, err)
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+
+	assert.Equal(t, 0, cache.size())
+	assert.Equal(t, int32(1), atomic.LoadInt32(&count))
+}
+
 func TestCacheWithLruEvicts(t *testing.T) {
 	cache, err := NewCache(time.Minute, WithLimit(3))
 	assert.Nil(t, err)
@@ -72,9 +123,9 @@ func TestCacheWithLruEvicts(t *testing.T) {
 	cache.Set("third", "third element")
 	cache.Set("fourth", "fourth element")
 
-	value, ok := cache.Get("first")
+	_, ok := cache.Get("first")
 	assert.False(t, ok)
-	value, ok = cache.Get("second")
+	value, ok := cache.Get("second")
 	assert.True(t, ok)
 	assert.Equal(t, "second element", value)
 	value, ok = cache.Get("third")
@@ -94,9 +145,9 @@ func TestCacheWithLruEvicted(t *testing.T) {
 	cache.Set("third", "third element")
 	cache.Set("fourth", "fourth element")
 
-	value, ok := cache.Get("first")
+	_, ok := cache.Get("first")
 	assert.False(t, ok)
-	value, ok = cache.Get("second")
+	value, ok := cache.Get("second")
 	assert.True(t, ok)
 	assert.Equal(t, "second element", value)
 	cache.Set("fifth", "fifth element")

core/collection/fifo.go

@@ -2,6 +2,7 @@ package collection
 
 import "sync"
 
+// A Queue is a FIFO queue.
 type Queue struct {
 	lock     sync.Mutex
 	elements []interface{}
@@ -11,6 +12,7 @@ type Queue struct {
 	count    int
 }
 
+// NewQueue returns a Queue object.
 func NewQueue(size int) *Queue {
 	return &Queue{
 		elements: make([]interface{}, size),
@@ -18,6 +20,7 @@ func NewQueue(size int) *Queue {
 	}
 }
 
+// Empty checks if q is empty.
 func (q *Queue) Empty() bool {
 	q.lock.Lock()
 	empty := q.count == 0
@@ -26,6 +29,7 @@ func (q *Queue) Empty() bool {
 	return empty
 }
 
+// Put puts element into q at the last position.
 func (q *Queue) Put(element interface{}) {
 	q.lock.Lock()
 	defer q.lock.Unlock()
@@ -44,6 +48,7 @@ func (q *Queue) Put(element interface{}) {
 	q.count++
 }
 
+// Take takes the first element out of q if not empty.
 func (q *Queue) Take() (interface{}, bool) {
 	q.lock.Lock()
 	defer q.lock.Unlock()

core/collection/ring.go

@@ -1,22 +1,39 @@
 package collection
 
+import "sync"
+
+// A Ring can be used as fixed size ring.
 type Ring struct {
 	elements []interface{}
 	index    int
+	lock     sync.Mutex
 }
 
+// NewRing returns a Ring object with the given size n.
 func NewRing(n int) *Ring {
+	if n < 1 {
+		panic("n should be greater than 0")
+	}
+
 	return &Ring{
 		elements: make([]interface{}, n),
 	}
 }
 
+// Add adds v into r.
 func (r *Ring) Add(v interface{}) {
+	r.lock.Lock()
+	defer r.lock.Unlock()
+
 	r.elements[r.index%len(r.elements)] = v
 	r.index++
 }
 
+// Take takes all items from r.
 func (r *Ring) Take() []interface{} {
+	r.lock.Lock()
+	defer r.lock.Unlock()
+
 	var size int
 	var start int
 	if r.index > len(r.elements) {

core/collection/ring_test.go

@@ -1,11 +1,18 @@
 package collection
 
 import (
+	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
+func TestNewRing(t *testing.T) {
+	assert.Panics(t, func() {
+		NewRing(0)
+	})
+}
+
 func TestRingLess(t *testing.T) {
 	ring := NewRing(5)
 	for i := 0; i < 3; i++ {
@@ -23,3 +30,30 @@ func TestRingMore(t *testing.T) {
 	elements := ring.Take()
 	assert.ElementsMatch(t, []interface{}{6, 7, 8, 9, 10}, elements)
 }
+
+func TestRingAdd(t *testing.T) {
+	ring := NewRing(5051)
+	wg := sync.WaitGroup{}
+	for i := 1; i <= 100; i++ {
+		wg.Add(1)
+		go func(i int) {
+			defer wg.Done()
+			for j := 1; j <= i; j++ {
+				ring.Add(i)
+			}
+		}(i)
+	}
+	wg.Wait()
+	assert.Equal(t, 5050, len(ring.Take()))
+}
+
+func BenchmarkRingAdd(b *testing.B) {
+	ring := NewRing(500)
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			for i := 0; i < b.N; i++ {
+				ring.Add(i)
+			}
+		}
+	})
+}

core/collection/rollingwindow.go

@@ -8,8 +8,10 @@ import (
 )
 
 type (
+	// RollingWindowOption let callers customize the RollingWindow.
 	RollingWindowOption func(rollingWindow *RollingWindow)
 
+	// RollingWindow defines a rolling window to calculate the events in buckets with time interval.
 	RollingWindow struct {
 		lock          sync.RWMutex
 		size          int
@@ -17,11 +19,17 @@ type (
 		interval      time.Duration
 		offset        int
 		ignoreCurrent bool
-		lastTime      time.Duration
+		lastTime      time.Duration // start time of the last bucket
 	}
 )
 
+// NewRollingWindow returns a RollingWindow that with size buckets and time interval,
+// use opts to customize the RollingWindow.
 func NewRollingWindow(size int, interval time.Duration, opts ...RollingWindowOption) *RollingWindow {
+	if size < 1 {
+		panic("size must be greater than 0")
+	}
+
 	w := &RollingWindow{
 		size:     size,
 		win:      newWindow(size),
@@ -34,6 +42,7 @@ func NewRollingWindow(size int, interval time.Duration, opts ...RollingWindowOpt
 	return w
 }
 
+// Add adds value to current bucket.
 func (rw *RollingWindow) Add(v float64) {
 	rw.lock.Lock()
 	defer rw.lock.Unlock()
@@ -41,6 +50,7 @@ func (rw *RollingWindow) Add(v float64) {
 	rw.win.add(rw.offset, v)
 }
 
+// Reduce runs fn on all buckets, ignore current bucket if ignoreCurrent was set.
 func (rw *RollingWindow) Reduce(fn func(b *Bucket)) {
 	rw.lock.RLock()
 	defer rw.lock.RUnlock()
@@ -63,36 +73,30 @@ func (rw *RollingWindow) span() int {
 	offset := int(timex.Since(rw.lastTime) / rw.interval)
 	if 0 <= offset && offset < rw.size {
 		return offset
-	} else {
-		return rw.size
 	}
+
+	return rw.size
 }
 
 func (rw *RollingWindow) updateOffset() {
 	span := rw.span()
-	if span > 0 {
+	if span <= 0 {
-		offset := rw.offset
+		return
-		// reset expired buckets
-		start := offset + 1
-		steps := start + span
-		var remainder int
-		if steps > rw.size {
-			remainder = steps - rw.size
-			steps = rw.size
-		}
-		for i := start; i < steps; i++ {
-			rw.win.resetBucket(i)
-			offset = i
-		}
-		for i := 0; i < remainder; i++ {
-			rw.win.resetBucket(i)
-			offset = i
-		}
-		rw.offset = offset
-		rw.lastTime = timex.Now()
 	}
+
+	offset := rw.offset
+	// reset expired buckets
+	for i := 0; i < span; i++ {
+		rw.win.resetBucket((offset + i + 1) % rw.size)
+	}
+
+	rw.offset = (offset + span) % rw.size
+	now := timex.Now()
+	// align to interval time boundary
+	rw.lastTime = now - (now-rw.lastTime)%rw.interval
 }
 
+// Bucket defines the bucket that holds sum and num of additions.
 type Bucket struct {
 	Sum   float64
 	Count int64
@@ -114,9 +118,9 @@ type window struct {
 }
 
 func newWindow(size int) *window {
-	var buckets []*Bucket
+	buckets := make([]*Bucket, size)
 	for i := 0; i < size; i++ {
-		buckets = append(buckets, new(Bucket))
+		buckets[i] = new(Bucket)
 	}
 	return &window{
 		buckets: buckets,
@@ -130,14 +134,15 @@ func (w *window) add(offset int, v float64) {
 
 func (w *window) reduce(start, count int, fn func(b *Bucket)) {
 	for i := 0; i < count; i++ {
-		fn(w.buckets[(start+i)%len(w.buckets)])
+		fn(w.buckets[(start+i)%w.size])
 	}
 }
 
 func (w *window) resetBucket(offset int) {
-	w.buckets[offset].reset()
+	w.buckets[offset%w.size].reset()
 }
 
+// IgnoreCurrentBucket lets the Reduce call ignore current bucket.
 func IgnoreCurrentBucket() RollingWindowOption {
 	return func(w *RollingWindow) {
 		w.ignoreCurrent = true

core/collection/rollingwindow_test.go

@@ -11,6 +11,13 @@ import (
 
 const duration = time.Millisecond * 50
 
+func TestNewRollingWindow(t *testing.T) {
+	assert.NotNil(t, NewRollingWindow(10, time.Second))
+	assert.Panics(t, func() {
+		NewRollingWindow(0, time.Second)
+	})
+}
+
 func TestRollingWindowAdd(t *testing.T) {
 	const size = 3
 	r := NewRollingWindow(size, duration)
@@ -81,7 +88,7 @@ func TestRollingWindowReduce(t *testing.T) {
 	for _, test := range tests {
 		t.Run(stringx.Rand(), func(t *testing.T) {
 			r := test.win
-			for x := 0; x < size; x = x + 1 {
+			for x := 0; x < size; x++ {
 				for i := 0; i <= x; i++ {
 					r.Add(float64(i))
 				}
@@ -98,10 +105,41 @@ func TestRollingWindowReduce(t *testing.T) {
 	}
 }
 
+func TestRollingWindowBucketTimeBoundary(t *testing.T) {
+	const size = 3
+	interval := time.Millisecond * 30
+	r := NewRollingWindow(size, interval)
+	listBuckets := func() []float64 {
+		var buckets []float64
+		r.Reduce(func(b *Bucket) {
+			buckets = append(buckets, b.Sum)
+		})
+		return buckets
+	}
+	assert.Equal(t, []float64{0, 0, 0}, listBuckets())
+	r.Add(1)
+	assert.Equal(t, []float64{0, 0, 1}, listBuckets())
+	time.Sleep(time.Millisecond * 45)
+	r.Add(2)
+	r.Add(3)
+	assert.Equal(t, []float64{0, 1, 5}, listBuckets())
+	// sleep time should be less than interval, and make the bucket change happen
+	time.Sleep(time.Millisecond * 20)
+	r.Add(4)
+	r.Add(5)
+	r.Add(6)
+	assert.Equal(t, []float64{1, 5, 15}, listBuckets())
+	time.Sleep(time.Millisecond * 100)
+	r.Add(7)
+	r.Add(8)
+	r.Add(9)
+	assert.Equal(t, []float64{0, 0, 24}, listBuckets())
+}
+
 func TestRollingWindowDataRace(t *testing.T) {
 	const size = 3
 	r := NewRollingWindow(size, duration)
-	var stop = make(chan bool)
+	stop := make(chan bool)
 	go func() {
 		for {
 			select {

core/collection/safemap.go

@@ -18,6 +18,7 @@ type SafeMap struct {
 	dirtyNew    map[interface{}]interface{}
 }
 
+// NewSafeMap returns a SafeMap.
 func NewSafeMap() *SafeMap {
 	return &SafeMap{
 		dirtyOld: make(map[interface{}]interface{}),
@@ -25,6 +26,7 @@ func NewSafeMap() *SafeMap {
 	}
 }
 
+// Del deletes the value with the given key from m.
 func (m *SafeMap) Del(key interface{}) {
 	m.lock.Lock()
 	if _, ok := m.dirtyOld[key]; ok {
@@ -53,18 +55,20 @@ func (m *SafeMap) Del(key interface{}) {
 	m.lock.Unlock()
 }
 
+// Get gets the value with the given key from m.
 func (m *SafeMap) Get(key interface{}) (interface{}, bool) {
 	m.lock.RLock()
 	defer m.lock.RUnlock()
 
 	if val, ok := m.dirtyOld[key]; ok {
 		return val, true
-	} else {
-		val, ok := m.dirtyNew[key]
-		return val, ok
 	}
+
+	val, ok := m.dirtyNew[key]
+	return val, ok
 }
 
+// Set sets the value into m with the given key.
 func (m *SafeMap) Set(key, value interface{}) {
 	m.lock.Lock()
 	if m.deletionOld <= maxDeletion {
@@ -83,6 +87,7 @@ func (m *SafeMap) Set(key, value interface{}) {
 	m.lock.Unlock()
 }
 
+// Size returns the size of m.
 func (m *SafeMap) Size() int {
 	m.lock.RLock()
 	size := len(m.dirtyOld) + len(m.dirtyNew)

core/collection/set.go

@@ -15,11 +15,13 @@ const (
 	stringType
 )
 
+// Set is not thread-safe, for concurrent use, make sure to use it with synchronization.
 type Set struct {
 	data map[interface{}]lang.PlaceholderType
 	tp   int
 }
 
+// NewSet returns a managed Set, can only put the values with the same type.
 func NewSet() *Set {
 	return &Set{
 		data: make(map[interface{}]lang.PlaceholderType),
@@ -27,6 +29,7 @@ func NewSet() *Set {
 	}
 }
 
+// NewUnmanagedSet returns a unmanaged Set, which can put values with different types.
 func NewUnmanagedSet() *Set {
 	return &Set{
 		data: make(map[interface{}]lang.PlaceholderType),
@@ -34,42 +37,49 @@ func NewUnmanagedSet() *Set {
 	}
 }
 
+// Add adds i into s.
 func (s *Set) Add(i ...interface{}) {
 	for _, each := range i {
 		s.add(each)
 	}
 }
 
+// AddInt adds int values ii into s.
 func (s *Set) AddInt(ii ...int) {
 	for _, each := range ii {
 		s.add(each)
 	}
 }
 
+// AddInt64 adds int64 values ii into s.
 func (s *Set) AddInt64(ii ...int64) {
 	for _, each := range ii {
 		s.add(each)
 	}
 }
 
+// AddUint adds uint values ii into s.
 func (s *Set) AddUint(ii ...uint) {
 	for _, each := range ii {
 		s.add(each)
 	}
 }
 
+// AddUint64 adds uint64 values ii into s.
 func (s *Set) AddUint64(ii ...uint64) {
 	for _, each := range ii {
 		s.add(each)
 	}
 }
 
+// AddStr adds string values ss into s.
 func (s *Set) AddStr(ss ...string) {
 	for _, each := range ss {
 		s.add(each)
 	}
 }
 
+// Contains checks if i is in s.
 func (s *Set) Contains(i interface{}) bool {
 	if len(s.data) == 0 {
 		return false
@@ -80,6 +90,7 @@ func (s *Set) Contains(i interface{}) bool {
 	return ok
 }
 
+// Keys returns the keys in s.
 func (s *Set) Keys() []interface{} {
 	var keys []interface{}
 
@@ -90,6 +101,7 @@ func (s *Set) Keys() []interface{} {
 	return keys
 }
 
+// KeysInt returns the int keys in s.
 func (s *Set) KeysInt() []int {
 	var keys []int
 
@@ -104,6 +116,7 @@ func (s *Set) KeysInt() []int {
 	return keys
 }
 
+// KeysInt64 returns int64 keys in s.
 func (s *Set) KeysInt64() []int64 {
 	var keys []int64
 
@@ -118,6 +131,7 @@ func (s *Set) KeysInt64() []int64 {
 	return keys
 }
 
+// KeysUint returns uint keys in s.
 func (s *Set) KeysUint() []uint {
 	var keys []uint
 
@@ -132,6 +146,7 @@ func (s *Set) KeysUint() []uint {
 	return keys
 }
 
+// KeysUint64 returns uint64 keys in s.
 func (s *Set) KeysUint64() []uint64 {
 	var keys []uint64
 
@@ -146,6 +161,7 @@ func (s *Set) KeysUint64() []uint64 {
 	return keys
 }
 
+// KeysStr returns string keys in s.
 func (s *Set) KeysStr() []string {
 	var keys []string
 
@@ -160,11 +176,13 @@ func (s *Set) KeysStr() []string {
 	return keys
 }
 
+// Remove removes i from s.
 func (s *Set) Remove(i interface{}) {
 	s.validate(i)
 	delete(s.data, i)
 }
 
+// Count returns the number of items in s.
 func (s *Set) Count() int {
 	return len(s.data)
 }
@@ -182,10 +200,7 @@ func (s *Set) add(i interface{}) {
 }
 
 func (s *Set) setType(i interface{}) {
-	if s.tp != untyped {
+	// s.tp can only be untyped here
-		return
-	}
-
 	switch i.(type) {
 	case int:
 		s.tp = intType

core/collection/set_test.go

@@ -5,8 +5,13 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/tal-tech/go-zero/core/logx"
 )
 
+func init() {
+	logx.Disable()
+}
+
 func BenchmarkRawSet(b *testing.B) {
 	m := make(map[interface{}]struct{})
 	for i := 0; i < b.N; i++ {
@@ -147,3 +152,51 @@ func TestCount(t *testing.T) {
 	// then
 	assert.Equal(t, set.Count(), 3)
 }
+
+func TestKeysIntMismatch(t *testing.T) {
+	set := NewSet()
+	set.add(int64(1))
+	set.add(2)
+	vals := set.KeysInt()
+	assert.EqualValues(t, []int{2}, vals)
+}
+
+func TestKeysInt64Mismatch(t *testing.T) {
+	set := NewSet()
+	set.add(1)
+	set.add(int64(2))
+	vals := set.KeysInt64()
+	assert.EqualValues(t, []int64{2}, vals)
+}
+
+func TestKeysUintMismatch(t *testing.T) {
+	set := NewSet()
+	set.add(1)
+	set.add(uint(2))
+	vals := set.KeysUint()
+	assert.EqualValues(t, []uint{2}, vals)
+}
+
+func TestKeysUint64Mismatch(t *testing.T) {
+	set := NewSet()
+	set.add(1)
+	set.add(uint64(2))
+	vals := set.KeysUint64()
+	assert.EqualValues(t, []uint64{2}, vals)
+}
+
+func TestKeysStrMismatch(t *testing.T) {
+	set := NewSet()
+	set.add(1)
+	set.add("2")
+	vals := set.KeysStr()
+	assert.EqualValues(t, []string{"2"}, vals)
+}
+
+func TestSetType(t *testing.T) {
+	set := NewUnmanagedSet()
+	set.add(1)
+	set.add("2")
+	vals := set.Keys()
+	assert.ElementsMatch(t, []interface{}{1, "2"}, vals)
+}

core/collection/timingwheel.go

@@ -13,8 +13,10 @@ import (
 const drainWorkers = 8
 
 type (
+	// Execute defines the method to execute the task.
 	Execute func(key, value interface{})
 
+	// A TimingWheel is a timing wheel object to schedule tasks.
 	TimingWheel struct {
 		interval      time.Duration
 		ticker        timex.Ticker
@@ -54,6 +56,7 @@ type (
 	}
 )
 
+// NewTimingWheel returns a TimingWheel.
 func NewTimingWheel(interval time.Duration, numSlots int, execute Execute) (*TimingWheel, error) {
 	if interval <= 0 || numSlots <= 0 || execute == nil {
 		return nil, fmt.Errorf("interval: %v, slots: %d, execute: %p", interval, numSlots, execute)
@@ -85,10 +88,12 @@ func newTimingWheelWithClock(interval time.Duration, numSlots int, execute Execu
 	return tw, nil
 }
 
+// Drain drains all items and executes them.
 func (tw *TimingWheel) Drain(fn func(key, value interface{})) {
 	tw.drainChannel <- fn
 }
 
+// MoveTimer moves the task with the given key to the given delay.
 func (tw *TimingWheel) MoveTimer(key interface{}, delay time.Duration) {
 	if delay <= 0 || key == nil {
 		return
@@ -100,6 +105,7 @@ func (tw *TimingWheel) MoveTimer(key interface{}, delay time.Duration) {
 	}
 }
 
+// RemoveTimer removes the task with the given key.
 func (tw *TimingWheel) RemoveTimer(key interface{}) {
 	if key == nil {
 		return
@@ -108,6 +114,7 @@ func (tw *TimingWheel) RemoveTimer(key interface{}) {
 	tw.removeChannel <- key
 }
 
+// SetTimer sets the task value with the given key to the delay.
 func (tw *TimingWheel) SetTimer(key, value interface{}, delay time.Duration) {
 	if delay <= 0 || key == nil {
 		return
@@ -122,6 +129,7 @@ func (tw *TimingWheel) SetTimer(key, value interface{}, delay time.Duration) {
 	}
 }
 
+// Stop stops tw.
 func (tw *TimingWheel) Stop() {
 	close(tw.stopChannel)
 }
@@ -204,6 +212,7 @@ func (tw *TimingWheel) removeTask(key interface{}) {
 
 	timer := val.(*positionEntry)
 	timer.item.removed = true
+	tw.timers.Del(key)
 }
 
 func (tw *TimingWheel) run() {
@@ -248,7 +257,6 @@ func (tw *TimingWheel) scanAndRunTasks(l *list.List) {
 		if task.removed {
 			next := e.Next()
 			l.Remove(e)
-			tw.timers.Del(task.key)
 			e = next
 			continue
 		} else if task.circle > 0 {
@@ -301,6 +309,7 @@ func (tw *TimingWheel) setTask(task *timingEntry) {
 func (tw *TimingWheel) setTimerPosition(pos int, task *timingEntry) {
 	if val, ok := tw.timers.Get(task.key); ok {
 		timer := val.(*positionEntry)
+		timer.item = task
 		timer.pos = pos
 	} else {
 		tw.timers.Set(task.key, &positionEntry{

core/collection/timingwheel_test.go

@@ -213,7 +213,10 @@ func TestTimingWheel_SetTimer(t *testing.T) {
 	}
 
 	for _, test := range tests {
+		test := test
 		t.Run(stringx.RandId(), func(t *testing.T) {
+			t.Parallel()
+
 			var count int32
 			ticker := timex.NewFakeTicker()
 			tick := func() {
@@ -291,7 +294,10 @@ func TestTimingWheel_SetAndMoveThenStart(t *testing.T) {
 	}
 
 	for _, test := range tests {
+		test := test
 		t.Run(stringx.RandId(), func(t *testing.T) {
+			t.Parallel()
+
 			var count int32
 			ticker := timex.NewFakeTicker()
 			tick := func() {
@@ -376,7 +382,10 @@ func TestTimingWheel_SetAndMoveTwice(t *testing.T) {
 	}
 
 	for _, test := range tests {
+		test := test
 		t.Run(stringx.RandId(), func(t *testing.T) {
+			t.Parallel()
+
 			var count int32
 			ticker := timex.NewFakeTicker()
 			tick := func() {
@@ -454,7 +463,10 @@ func TestTimingWheel_ElapsedAndSet(t *testing.T) {
 	}
 
 	for _, test := range tests {
+		test := test
 		t.Run(stringx.RandId(), func(t *testing.T) {
+			t.Parallel()
+
 			var count int32
 			ticker := timex.NewFakeTicker()
 			tick := func() {
@@ -542,7 +554,10 @@ func TestTimingWheel_ElapsedAndSetThenMove(t *testing.T) {
 	}
 
 	for _, test := range tests {
+		test := test
 		t.Run(stringx.RandId(), func(t *testing.T) {
+			t.Parallel()
+
 			var count int32
 			ticker := timex.NewFakeTicker()
 			tick := func() {
@@ -579,6 +594,31 @@ func TestTimingWheel_ElapsedAndSetThenMove(t *testing.T) {
 	}
 }
 
+func TestMoveAndRemoveTask(t *testing.T) {
+	ticker := timex.NewFakeTicker()
+	tick := func(v int) {
+		for i := 0; i < v; i++ {
+			ticker.Tick()
+		}
+	}
+	var keys []int
+	tw, _ := newTimingWheelWithClock(testStep, 10, func(k, v interface{}) {
+		assert.Equal(t, "any", k)
+		assert.Equal(t, 3, v.(int))
+		keys = append(keys, v.(int))
+		ticker.Done()
+	}, ticker)
+	defer tw.Stop()
+	tw.SetTimer("any", 3, testStep*8)
+	tick(6)
+	tw.MoveTimer("any", testStep*7)
+	tick(3)
+	tw.RemoveTimer("any")
+	tick(30)
+	time.Sleep(time.Millisecond)
+	assert.Equal(t, 0, len(keys))
+}
+
 func BenchmarkTimingWheel(b *testing.B) {
 	b.ReportAllocs()
 

core/conf/config.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"log"
+	"os"
 	"path"
 
 	"github.com/tal-tech/go-zero/core/mapping"
@@ -15,26 +16,43 @@ var loaders = map[string]func([]byte, interface{}) error{
 	".yml":  LoadConfigFromYamlBytes,
 }
 
-func LoadConfig(file string, v interface{}) error {
+// LoadConfig loads config into v from file, .json, .yaml and .yml are acceptable.
-	if content, err := ioutil.ReadFile(file); err != nil {
+func LoadConfig(file string, v interface{}, opts ...Option) error {
+	content, err := ioutil.ReadFile(file)
+	if err != nil {
 		return err
-	} else if loader, ok := loaders[path.Ext(file)]; ok {
-		return loader(content, v)
-	} else {
-		return fmt.Errorf("unrecoginized file type: %s", file)
 	}
+
+	loader, ok := loaders[path.Ext(file)]
+	if !ok {
+		return fmt.Errorf("unrecognized file type: %s", file)
+	}
+
+	var opt options
+	for _, o := range opts {
+		o(&opt)
+	}
+
+	if opt.env {
+		return loader([]byte(os.ExpandEnv(string(content))), v)
+	}
+
+	return loader(content, v)
 }
 
+// LoadConfigFromJsonBytes loads config into v from content json bytes.
 func LoadConfigFromJsonBytes(content []byte, v interface{}) error {
 	return mapping.UnmarshalJsonBytes(content, v)
 }
 
+// LoadConfigFromYamlBytes loads config into v from content yaml bytes.
 func LoadConfigFromYamlBytes(content []byte, v interface{}) error {
 	return mapping.UnmarshalYamlBytes(content, v)
 }
 
-func MustLoad(path string, v interface{}) {
+// MustLoad loads config into v from path, exits on error.
-	if err := LoadConfig(path, v); err != nil {
+func MustLoad(path string, v interface{}, opts ...Option) {
+	if err := LoadConfig(path, v, opts...); err != nil {
 		log.Fatalf("error: config file %s, %s", path, err.Error())
 	}
 }

core/conf/config_test.go

@@ -0,0 +1,112 @@
+package conf
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/tal-tech/go-zero/core/fs"
+	"github.com/tal-tech/go-zero/core/hash"
+)
+
+func TestLoadConfig_notExists(t *testing.T) {
+	assert.NotNil(t, LoadConfig("not_a_file", nil))
+}
+
+func TestLoadConfig_notRecogFile(t *testing.T) {
+	filename, err := fs.TempFilenameWithText("hello")
+	assert.Nil(t, err)
+	defer os.Remove(filename)
+	assert.NotNil(t, LoadConfig(filename, nil))
+}
+
+func TestConfigJson(t *testing.T) {
+	tests := []string{
+		".json",
+		".yaml",
+		".yml",
+	}
+	text := `{
+	"a": "foo",
+	"b": 1,
+	"c": "${FOO}",
+	"d": "abcd!@#$112"
+}`
+	for _, test := range tests {
+		test := test
+		t.Run(test, func(t *testing.T) {
+			os.Setenv("FOO", "2")
+			defer os.Unsetenv("FOO")
+			tmpfile, err := createTempFile(test, text)
+			assert.Nil(t, err)
+			defer os.Remove(tmpfile)
+
+			var val struct {
+				A string `json:"a"`
+				B int    `json:"b"`
+				C string `json:"c"`
+				D string `json:"d"`
+			}
+			MustLoad(tmpfile, &val)
+			assert.Equal(t, "foo", val.A)
+			assert.Equal(t, 1, val.B)
+			assert.Equal(t, "${FOO}", val.C)
+			assert.Equal(t, "abcd!@#$112", val.D)
+		})
+	}
+}
+
+func TestConfigJsonEnv(t *testing.T) {
+	tests := []string{
+		".json",
+		".yaml",
+		".yml",
+	}
+	text := `{
+	"a": "foo",
+	"b": 1,
+	"c": "${FOO}",
+	"d": "abcd!@#$a12 3"
+}`
+	for _, test := range tests {
+		test := test
+		t.Run(test, func(t *testing.T) {
+			os.Setenv("FOO", "2")
+			defer os.Unsetenv("FOO")
+			tmpfile, err := createTempFile(test, text)
+			assert.Nil(t, err)
+			defer os.Remove(tmpfile)
+
+			var val struct {
+				A string `json:"a"`
+				B int    `json:"b"`
+				C string `json:"c"`
+				D string `json:"d"`
+			}
+			MustLoad(tmpfile, &val, UseEnv())
+			assert.Equal(t, "foo", val.A)
+			assert.Equal(t, 1, val.B)
+			assert.Equal(t, "2", val.C)
+			assert.Equal(t, "abcd!@# 3", val.D)
+		})
+	}
+}
+
+func createTempFile(ext, text string) (string, error) {
+	tmpfile, err := ioutil.TempFile(os.TempDir(), hash.Md5Hex([]byte(text))+"*"+ext)
+	if err != nil {
+		return "", err
+	}
+
+	if err := ioutil.WriteFile(tmpfile.Name(), []byte(text), os.ModeTemporary); err != nil {
+		return "", err
+	}
+
+	filename := tmpfile.Name()
+	if err = tmpfile.Close(); err != nil {
+		return "", err
+	}
+
+	return filename, nil
+}

core/conf/options.go

@@ -0,0 +1,17 @@
+package conf
+
+type (
+	// Option defines the method to customize the config options.
+	Option func(opt *options)
+
+	options struct {
+		env bool
+	}
+)
+
+// UseEnv customizes the config to use environment variables.
+func UseEnv() Option {
+	return func(opt *options) {
+		opt.env = true
+	}
+}

core/conf/properties.go

@@ -2,6 +2,7 @@ package conf
 
 import (
 	"fmt"
+	"os"
 	"strconv"
 	"strings"
 	"sync"
@@ -30,12 +31,17 @@ type mapBasedProperties struct {
 	lock       sync.RWMutex
 }
 
-// Loads the properties into a properties configuration instance. May return the
+// LoadProperties loads the properties into a properties configuration instance.
-// configuration itself along with an error that indicates if there was a problem loading the configuration.
+// Returns an error that indicates if there was a problem loading the configuration.
-func LoadProperties(filename string) (Properties, error) {
+func LoadProperties(filename string, opts ...Option) (Properties, error) {
 	lines, err := iox.ReadTextLines(filename, iox.WithoutBlank(), iox.OmitWithPrefix("#"))
 	if err != nil {
-		return nil, nil
+		return nil, err
+	}
+
+	var opt options
+	for _, o := range opts {
+		o(&opt)
 	}
 
 	raw := make(map[string]string)
@@ -50,7 +56,11 @@ func LoadProperties(filename string) (Properties, error) {
 
 		key := strings.TrimSpace(pair[0])
 		value := strings.TrimSpace(pair[1])
-		raw[key] = value
+		if opt.env {
+			raw[key] = os.ExpandEnv(value)
+		} else {
+			raw[key] = value
+		}
 	}
 
 	return &mapBasedProperties{
@@ -87,7 +97,7 @@ func (config *mapBasedProperties) SetInt(key string, value int) {
 	config.lock.Unlock()
 }
 
-// Dumps the configuration internal map into a string.
+// ToString dumps the configuration internal map into a string.
 func (config *mapBasedProperties) ToString() string {
 	config.lock.RLock()
 	ret := fmt.Sprintf("%s", config.properties)
@@ -96,12 +106,12 @@ func (config *mapBasedProperties) ToString() string {
 	return ret
 }
 
-// Returns the error message.
+// Error returns the error message.
 func (configError *PropertyError) Error() string {
 	return configError.message
 }
 
-// Builds a new properties configuration structure
+// NewProperties builds a new properties configuration structure.
 func NewProperties() Properties {
 	return &mapBasedProperties{
 		properties: make(map[string]string),

core/conf/properties_test.go

@@ -24,6 +24,53 @@ func TestProperties(t *testing.T) {
 	assert.Equal(t, "test", props.GetString("app.name"))
 	assert.Equal(t, "app", props.GetString("app.program"))
 	assert.Equal(t, 5, props.GetInt("app.threads"))
+
+	val := props.ToString()
+	assert.Contains(t, val, "app.name")
+	assert.Contains(t, val, "app.program")
+	assert.Contains(t, val, "app.threads")
+}
+
+func TestPropertiesEnv(t *testing.T) {
+	text := `app.name = test
+
+    app.program=app
+
+	app.env1 = ${FOO}
+	app.env2 = $none
+
+    # this is comment
+    app.threads = 5`
+	tmpfile, err := fs.TempFilenameWithText(text)
+	assert.Nil(t, err)
+	defer os.Remove(tmpfile)
+
+	os.Setenv("FOO", "2")
+	defer os.Unsetenv("FOO")
+
+	props, err := LoadProperties(tmpfile, UseEnv())
+	assert.Nil(t, err)
+	assert.Equal(t, "test", props.GetString("app.name"))
+	assert.Equal(t, "app", props.GetString("app.program"))
+	assert.Equal(t, 5, props.GetInt("app.threads"))
+	assert.Equal(t, "2", props.GetString("app.env1"))
+	assert.Equal(t, "", props.GetString("app.env2"))
+
+	val := props.ToString()
+	assert.Contains(t, val, "app.name")
+	assert.Contains(t, val, "app.program")
+	assert.Contains(t, val, "app.threads")
+	assert.Contains(t, val, "app.env1")
+	assert.Contains(t, val, "app.env2")
+}
+
+func TestLoadProperties_badContent(t *testing.T) {
+	filename, err := fs.TempFilenameWithText("hello")
+	assert.Nil(t, err)
+	defer os.Remove(filename)
+	_, err = LoadProperties(filename)
+	assert.NotNil(t, err)
+	assert.True(t, len(err.Error()) > 0)
 }
 
 func TestSetString(t *testing.T) {
@@ -41,3 +88,8 @@ func TestSetInt(t *testing.T) {
 	props.SetInt(key, value)
 	assert.Equal(t, value, props.GetInt(key))
 }
+
+func TestLoadBadFile(t *testing.T) {
+	_, err := LoadProperties("nosuchfile")
+	assert.NotNil(t, err)
+}

core/contextx/deadline.go

@@ -1,17 +0,0 @@
-package contextx
-
-import (
-	"context"
-	"time"
-)
-
-func ShrinkDeadline(ctx context.Context, timeout time.Duration) (context.Context, func()) {
-	if deadline, ok := ctx.Deadline(); ok {
-		leftTime := time.Until(deadline)
-		if leftTime < timeout {
-			timeout = leftTime
-		}
-	}
-
-	return context.WithDeadline(ctx, time.Now().Add(timeout))
-}

core/contextx/deadline_test.go

@@ -1,27 +0,0 @@
-package contextx
-
-import (
-	"context"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-)
-
-func TestShrinkDeadlineLess(t *testing.T) {
-	deadline := time.Now().Add(time.Second)
-	ctx, _ := context.WithDeadline(context.Background(), deadline)
-	ctx, _ = ShrinkDeadline(ctx, time.Minute)
-	dl, ok := ctx.Deadline()
-	assert.True(t, ok)
-	assert.Equal(t, deadline, dl)
-}
-
-func TestShrinkDeadlineMore(t *testing.T) {
-	deadline := time.Now().Add(time.Minute)
-	ctx, _ := context.WithDeadline(context.Background(), deadline)
-	ctx, _ = ShrinkDeadline(ctx, time.Second)
-	dl, ok := ctx.Deadline()
-	assert.True(t, ok)
-	assert.True(t, dl.Before(deadline))
-}

core/contextx/unmarshaler.go

@@ -19,6 +19,7 @@ func (cv contextValuer) Value(key string) (interface{}, bool) {
 	return v, v != nil
 }
 
+// For unmarshals ctx into v.
 func For(ctx context.Context, v interface{}) error {
 	return unmarshaler.UnmarshalValuer(contextValuer{
 		Context: ctx,

core/contextx/valueonlycontext.go

@@ -21,6 +21,7 @@ func (valueOnlyContext) Err() error {
 	return nil
 }
 
+// ValueOnlyFrom takes all values from the given ctx, without deadline and error control.
 func ValueOnlyFrom(ctx context.Context) context.Context {
 	return valueOnlyContext{
 		Context: ctx,

core/contextx/valueonlycontext_test.go

@@ -12,7 +12,8 @@ func TestContextCancel(t *testing.T) {
 	c := context.WithValue(context.Background(), "key", "value")
 	c1, cancel := context.WithCancel(c)
 	o := ValueOnlyFrom(c1)
-	c2, _ := context.WithCancel(o)
+	c2, cancel2 := context.WithCancel(o)
+	defer cancel2()
 	contexts := []context.Context{c1, c2}
 
 	for _, c := range contexts {
@@ -34,8 +35,9 @@ func TestContextCancel(t *testing.T) {
 	assert.NotEqual(t, context.Canceled, c2.Err())
 }
 
-func TestConextDeadline(t *testing.T) {
+func TestContextDeadline(t *testing.T) {
-	c, _ := context.WithDeadline(context.Background(), time.Now().Add(10*time.Millisecond))
+	c, cancel := context.WithDeadline(context.Background(), time.Now().Add(10*time.Millisecond))
+	cancel()
 	o := ValueOnlyFrom(c)
 	select {
 	case <-time.After(100 * time.Millisecond):
@@ -43,9 +45,11 @@ func TestConextDeadline(t *testing.T) {
 		t.Fatal("ValueOnlyContext: context should not have timed out")
 	}
 
-	c, _ = context.WithDeadline(context.Background(), time.Now().Add(10*time.Millisecond))
+	c, cancel = context.WithDeadline(context.Background(), time.Now().Add(10*time.Millisecond))
+	cancel()
 	o = ValueOnlyFrom(c)
-	c, _ = context.WithDeadline(o, time.Now().Add(20*time.Millisecond))
+	c, cancel = context.WithDeadline(o, time.Now().Add(20*time.Millisecond))
+	defer cancel()
 	select {
 	case <-time.After(100 * time.Millisecond):
 		t.Fatal("ValueOnlyContext+Deadline: context should have timed out")

core/discov/clients.go

@@ -8,12 +8,13 @@ import (
 )
 
 const (
-	indexOfKey = iota
+	_ = iota
 	indexOfId
 )
 
 const timeToLive int64 = 10
 
+// TimeToLive is seconds to live in etcd.
 var TimeToLive = timeToLive
 
 func extract(etcdKey string, index int) (string, bool) {

core/discov/clients_test.go

@@ -28,6 +28,9 @@ func TestExtract(t *testing.T) {
 
 	_, ok = extract("any", -1)
 	assert.False(t, ok)
+
+	_, ok = extract("any", 10)
+	assert.False(t, ok)
 }
 
 func TestMakeKey(t *testing.T) {

core/discov/config.go

@@ -2,11 +2,13 @@ package discov
 
 import "errors"
 
+// EtcdConf is the config item with the given key on etcd.
 type EtcdConf struct {
 	Hosts []string
 	Key   string
 }
 
+// Validate validates c.
 func (c EtcdConf) Validate() error {
 	if len(c.Hosts) == 0 {
 		return errors.New("empty etcd hosts")

core/discov/facade.go

@@ -1,47 +0,0 @@
-package discov
-
-import (
-	"github.com/tal-tech/go-zero/core/discov/internal"
-	"github.com/tal-tech/go-zero/core/lang"
-)
-
-type (
-	Facade struct {
-		endpoints []string
-		registry  *internal.Registry
-	}
-
-	FacadeListener interface {
-		OnAdd(key, val string)
-		OnDelete(key string)
-	}
-)
-
-func NewFacade(endpoints []string) Facade {
-	return Facade{
-		endpoints: endpoints,
-		registry:  internal.GetRegistry(),
-	}
-}
-
-func (f Facade) Client() internal.EtcdClient {
-	conn, err := f.registry.GetConn(f.endpoints)
-	lang.Must(err)
-	return conn
-}
-
-func (f Facade) Monitor(key string, l FacadeListener) {
-	f.registry.Monitor(f.endpoints, key, listenerAdapter{l})
-}
-
-type listenerAdapter struct {
-	l FacadeListener
-}
-
-func (la listenerAdapter) OnAdd(kv internal.KV) {
-	la.l.OnAdd(kv.Key, kv.Val)
-}
-
-func (la listenerAdapter) OnDelete(kv internal.KV) {
-	la.l.OnDelete(kv.Key)
-}

core/discov/internal/etcdclient.go

@@ -1,4 +1,5 @@
 //go:generate mockgen -package internal -destination etcdclient_mock.go -source etcdclient.go EtcdClient
+
 package internal
 
 import (
@@ -8,6 +9,7 @@ import (
 	"google.golang.org/grpc"
 )
 
+// EtcdClient interface represents an etcd client.
 type EtcdClient interface {
 	ActiveConnection() *grpc.ClientConn
 	Close() error

core/discov/internal/listener.go

@@ -1,6 +1,6 @@
-//go:generate mockgen -package internal -destination listener_mock.go -source listener.go Listener
 package internal
 
+// Listener interface wraps the OnUpdate method.
 type Listener interface {
 	OnUpdate(keys []string, values []string, newKey string)
 }

core/discov/internal/listener_mock.go

@@ -1,45 +0,0 @@
-// Code generated by MockGen. DO NOT EDIT.
-// Source: listener.go
-
-// Package internal is a generated GoMock package.
-package internal
-
-import (
-	gomock "github.com/golang/mock/gomock"
-	reflect "reflect"
-)
-
-// MockListener is a mock of Listener interface
-type MockListener struct {
-	ctrl     *gomock.Controller
-	recorder *MockListenerMockRecorder
-}
-
-// MockListenerMockRecorder is the mock recorder for MockListener
-type MockListenerMockRecorder struct {
-	mock *MockListener
-}
-
-// NewMockListener creates a new mock instance
-func NewMockListener(ctrl *gomock.Controller) *MockListener {
-	mock := &MockListener{ctrl: ctrl}
-	mock.recorder = &MockListenerMockRecorder{mock}
-	return mock
-}
-
-// EXPECT returns an object that allows the caller to indicate expected use
-func (m *MockListener) EXPECT() *MockListenerMockRecorder {
-	return m.recorder
-}
-
-// OnUpdate mocks base method
-func (m *MockListener) OnUpdate(keys, values []string, newKey string) {
-	m.ctrl.T.Helper()
-	m.ctrl.Call(m, "OnUpdate", keys, values, newKey)
-}
-
-// OnUpdate indicates an expected call of OnUpdate
-func (mr *MockListenerMockRecorder) OnUpdate(keys, values, newKey interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "OnUpdate", reflect.TypeOf((*MockListener)(nil).OnUpdate), keys, values, newKey)
-}

core/discov/internal/registry.go

@@ -18,19 +18,31 @@ import (
 )
 
 var (
-	registryInstance = Registry{
+	registry = Registry{
 		clusters: make(map[string]*cluster),
 	}
 	connManager = syncx.NewResourceManager()
 )
 
+// A Registry is a registry that manages the etcd client connections.
 type Registry struct {
 	clusters map[string]*cluster
 	lock     sync.Mutex
 }
 
+// GetRegistry returns a global Registry.
 func GetRegistry() *Registry {
-	return &registryInstance
+	return &registry
+}
+
+// GetConn returns an etcd client connection associated with given endpoints.
+func (r *Registry) GetConn(endpoints []string) (EtcdClient, error) {
+	return r.getCluster(endpoints).getClient()
+}
+
+// Monitor monitors the key on given etcd endpoints, notify with the given UpdateListener.
+func (r *Registry) Monitor(endpoints []string, key string, l UpdateListener) error {
+	return r.getCluster(endpoints).monitor(key, l)
 }
 
 func (r *Registry) getCluster(endpoints []string) *cluster {
@@ -46,14 +58,6 @@ func (r *Registry) getCluster(endpoints []string) *cluster {
 	return c
 }
 
-func (r *Registry) GetConn(endpoints []string) (EtcdClient, error) {
-	return r.getCluster(endpoints).getClient()
-}
-
-func (r *Registry) Monitor(endpoints []string, key string, l UpdateListener) error {
-	return r.getCluster(endpoints).monitor(key, l)
-}
-
 type cluster struct {
 	endpoints  []string
 	key        string
@@ -288,6 +292,7 @@ func (c *cluster) watchConnState(cli EtcdClient) {
 	watcher.watch(cli.ActiveConnection())
 }
 
+// DialClient dials an etcd cluster with given endpoints.
 func DialClient(endpoints []string) (EtcdClient, error) {
 	return clientv3.New(clientv3.Config{
 		Endpoints:            endpoints,

core/discov/internal/statewatcher.go

@@ -1,4 +1,5 @@
 //go:generate mockgen -package internal -destination statewatcher_mock.go -source statewatcher.go etcdConn
+
 package internal
 
 import (
@@ -18,7 +19,8 @@ type (
 		disconnected bool
 		currentState connectivity.State
 		listeners    []func()
-		lock         sync.Mutex
+		// lock only guards listeners, because only listens can be accessed by other goroutines.
+		lock sync.Mutex
 	}
 )
 
@@ -32,27 +34,33 @@ func (sw *stateWatcher) addListener(l func()) {
 	sw.lock.Unlock()
 }
 
+func (sw *stateWatcher) notifyListeners() {
+	sw.lock.Lock()
+	defer sw.lock.Unlock()
+
+	for _, l := range sw.listeners {
+		l()
+	}
+}
+
+func (sw *stateWatcher) updateState(conn etcdConn) {
+	sw.currentState = conn.GetState()
+	switch sw.currentState {
+	case connectivity.TransientFailure, connectivity.Shutdown:
+		sw.disconnected = true
+	case connectivity.Ready:
+		if sw.disconnected {
+			sw.disconnected = false
+			sw.notifyListeners()
+		}
+	}
+}
+
 func (sw *stateWatcher) watch(conn etcdConn) {
 	sw.currentState = conn.GetState()
 	for {
 		if conn.WaitForStateChange(context.Background(), sw.currentState) {
-			newState := conn.GetState()
+			sw.updateState(conn)
-			sw.lock.Lock()
-			sw.currentState = newState
-
-			switch newState {
-			case connectivity.TransientFailure, connectivity.Shutdown:
-				sw.disconnected = true
-			case connectivity.Ready:
-				if sw.disconnected {
-					sw.disconnected = false
-					for _, l := range sw.listeners {
-						l()
-					}
-				}
-			}
-
-			sw.lock.Unlock()
 		}
 	}
 }

core/discov/internal/updatelistener.go

@@ -1,12 +1,15 @@
 //go:generate mockgen -package internal -destination updatelistener_mock.go -source updatelistener.go UpdateListener
+
 package internal
 
 type (
+	// A KV is used to store an etcd entry with key and value.
 	KV struct {
 		Key string
 		Val string
 	}
 
+	// UpdateListener wraps the OnAdd and OnDelete methods.
 	UpdateListener interface {
 		OnAdd(kv KV)
 		OnDelete(kv KV)

core/discov/internal/vars.go

@@ -3,17 +3,22 @@ package internal
 import "time"
 
 const (
+	// Delimiter is a separator that separates the etcd path.
+	Delimiter = '/'
+
 	autoSyncInterval   = time.Minute
 	coolDownInterval   = time.Second
 	dialTimeout        = 5 * time.Second
 	dialKeepAliveTime  = 5 * time.Second
 	requestTimeout     = 3 * time.Second
-	Delimiter          = '/'
 	endpointsSeparator = ","
 )
 
 var (
-	DialTimeout    = dialTimeout
+	// DialTimeout is the dial timeout.
+	DialTimeout = dialTimeout
+	// RequestTimeout is the request timeout.
 	RequestTimeout = requestTimeout
-	NewClient      = DialClient
+	// NewClient is used to create etcd clients.
+	NewClient = DialClient
 )

core/discov/kubernetes/etcd-statefulset.yaml

@@ -0,0 +1,64 @@
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: "etcd"
+  namespace: discov
+  labels:
+    app: "etcd"
+spec:
+  serviceName: "etcd"
+  replicas: 5
+  template:
+    metadata:
+      name: "etcd"
+      labels:
+        app: "etcd"
+    spec:
+      volumes:
+      - name: etcd-pvc
+        persistentVolumeClaim:
+          claimName: etcd-pvc
+      containers:
+      - name: "etcd"
+        image: quay.io/coreos/etcd:latest
+        ports:
+        - containerPort: 2379
+          name: client
+        - containerPort: 2380
+          name: peer
+        env:
+        - name: CLUSTER_SIZE
+          value: "5"
+        - name: SET_NAME
+          value: "etcd"
+        - name: VOLNAME
+          valueFrom:
+            fieldRef:
+              apiVersion: v1
+              fieldPath: metadata.name
+        volumeMounts:
+        - name: etcd-pvc
+          mountPath: /var/lib/etcd
+          subPathExpr: $(VOLNAME)  # data mounted respectively in each pod
+        command:
+          - "/bin/sh"
+          - "-ecx"
+          - |
+
+            chmod 700 /var/lib/etcd
+
+            IP=$(hostname -i)
+            PEERS=""
+            for i in $(seq 0 $((${CLUSTER_SIZE} - 1))); do
+                PEERS="${PEERS}${PEERS:+,}${SET_NAME}-${i}=http://${SET_NAME}-${i}.${SET_NAME}:2380"
+            done
+            exec etcd --name ${HOSTNAME} \
+              --listen-peer-urls http://0.0.0.0:2380 \
+              --listen-client-urls http://0.0.0.0:2379 \
+              --advertise-client-urls http://${HOSTNAME}.${SET_NAME}.discov:2379 \
+              --initial-advertise-peer-urls http://${HOSTNAME}.${SET_NAME}:2380 \
+              --initial-cluster ${PEERS} \
+              --initial-cluster-state new \
+              --logger zap \
+              --data-dir /var/lib/etcd \
+              --auto-compaction-retention 1

core/discov/kubernetes/etcd.yaml

@@ -1,16 +1,16 @@
 apiVersion: v1
 kind: Service
 metadata:
-  name: discov
+  name: etcd
-  namespace: discovery
+  namespace: discov
 spec:
   ports:
-    - name: discov-port
+    - name: etcd-port
       port: 2379
       protocol: TCP
       targetPort: 2379
   selector:
-    app: discov
+    app: etcd
 
 ---
 
@@ -18,30 +18,31 @@ apiVersion: v1
 kind: Pod
 metadata:
   labels:
-    app: discov
+    app: etcd
-    discov_node: discov0
+    etcd_node: etcd0
-  name: discov0
+  name: etcd0
-  namespace: discovery
+  namespace: discov
 spec:
   containers:
     - command:
         - /usr/local/bin/etcd
         - --name
-        - discov0
+        - etcd0
         - --initial-advertise-peer-urls
-        - http://discov0:2380
+        - http://etcd0:2380
         - --listen-peer-urls
         - http://0.0.0.0:2380
         - --listen-client-urls
         - http://0.0.0.0:2379
         - --advertise-client-urls
-        - http://discov0:2379
+        - http://etcd0.discov:2379
         - --initial-cluster
-        - discov0=http://discov0:2380,discov1=http://discov1:2380,discov2=http://discov2:2380,discov3=http://discov3:2380,discov4=http://discov4:2380
+        - etcd0=http://etcd0:2380,etcd1=http://etcd1:2380,etcd2=http://etcd2:2380,etcd3=http://etcd3:2380,etcd4=http://etcd4:2380
         - --initial-cluster-state
         - new
-      image: registry-vpc.cn-hangzhou.aliyuncs.com/xapp/etcd:latest
+        - --auto-compaction-retention=1
-      name: discov0
+      image: quay.io/coreos/etcd:latest
+      name: etcd0
       ports:
         - containerPort: 2379
           name: client
@@ -49,8 +50,6 @@ spec:
         - containerPort: 2380
           name: server
           protocol: TCP
-  imagePullSecrets:
-    - name: aliyun
   affinity:
     podAntiAffinity:
       requiredDuringSchedulingIgnoredDuringExecution:
@@ -59,7 +58,7 @@ spec:
               - key: app
                 operator: In
                 values:
-                  - discov
+                  - etcd
           topologyKey: "kubernetes.io/hostname"
   restartPolicy: Always
 
@@ -69,9 +68,9 @@ apiVersion: v1
 kind: Service
 metadata:
   labels:
-    discov_node: discov0
+    etcd_node: etcd0
-  name: discov0
+  name: etcd0
-  namespace: discovery
+  namespace: discov
 spec:
   ports:
     - name: client
@@ -83,7 +82,7 @@ spec:
       protocol: TCP
       targetPort: 2380
   selector:
-    discov_node: discov0
+    etcd_node: etcd0
 
 ---
 
@@ -91,30 +90,31 @@ apiVersion: v1
 kind: Pod
 metadata:
   labels:
-    app: discov
+    app: etcd
-    discov_node: discov1
+    etcd_node: etcd1
-  name: discov1
+  name: etcd1
-  namespace: discovery
+  namespace: discov
 spec:
   containers:
     - command:
         - /usr/local/bin/etcd
         - --name
-        - discov1
+        - etcd1
         - --initial-advertise-peer-urls
-        - http://discov1:2380
+        - http://etcd1:2380
         - --listen-peer-urls
         - http://0.0.0.0:2380
         - --listen-client-urls
         - http://0.0.0.0:2379
         - --advertise-client-urls
-        - http://discov1:2379
+        - http://etcd1.discov:2379
         - --initial-cluster
-        - discov0=http://discov0:2380,discov1=http://discov1:2380,discov2=http://discov2:2380,discov3=http://discov3:2380,discov4=http://discov4:2380
+        - etcd0=http://etcd0:2380,etcd1=http://etcd1:2380,etcd2=http://etcd2:2380,etcd3=http://etcd3:2380,etcd4=http://etcd4:2380
         - --initial-cluster-state
         - new
-      image: registry-vpc.cn-hangzhou.aliyuncs.com/xapp/etcd:latest
+        - --auto-compaction-retention=1
-      name: discov1
+      image: quay.io/coreos/etcd:latest
+      name: etcd1
       ports:
         - containerPort: 2379
           name: client
@@ -122,8 +122,6 @@ spec:
         - containerPort: 2380
           name: server
           protocol: TCP
-  imagePullSecrets:
-    - name: aliyun
   affinity:
     podAntiAffinity:
       requiredDuringSchedulingIgnoredDuringExecution:
@@ -132,7 +130,7 @@ spec:
               - key: app
                 operator: In
                 values:
-                  - discov
+                  - etcd
           topologyKey: "kubernetes.io/hostname"
   restartPolicy: Always
 
@@ -142,9 +140,9 @@ apiVersion: v1
 kind: Service
 metadata:
   labels:
-    discov_node: discov1
+    etcd_node: etcd1
-  name: discov1
+  name: etcd1
-  namespace: discovery
+  namespace: discov
 spec:
   ports:
     - name: client
@@ -156,7 +154,7 @@ spec:
       protocol: TCP
       targetPort: 2380
   selector:
-    discov_node: discov1
+    etcd_node: etcd1
 
 ---
 
@@ -164,30 +162,31 @@ apiVersion: v1
 kind: Pod
 metadata:
   labels:
-    app: discov
+    app: etcd
-    discov_node: discov2
+    etcd_node: etcd2
-  name: discov2
+  name: etcd2
-  namespace: discovery
+  namespace: discov
 spec:
   containers:
     - command:
         - /usr/local/bin/etcd
         - --name
-        - discov2
+        - etcd2
         - --initial-advertise-peer-urls
-        - http://discov2:2380
+        - http://etcd2:2380
         - --listen-peer-urls
         - http://0.0.0.0:2380
         - --listen-client-urls
         - http://0.0.0.0:2379
         - --advertise-client-urls
-        - http://discov2:2379
+        - http://etcd2.discov:2379
         - --initial-cluster
-        - discov0=http://discov0:2380,discov1=http://discov1:2380,discov2=http://discov2:2380,discov3=http://discov3:2380,discov4=http://discov4:2380
+        - etcd0=http://etcd0:2380,etcd1=http://etcd1:2380,etcd2=http://etcd2:2380,etcd3=http://etcd3:2380,etcd4=http://etcd4:2380
         - --initial-cluster-state
         - new
-      image: registry-vpc.cn-hangzhou.aliyuncs.com/xapp/etcd:latest
+        - --auto-compaction-retention=1
-      name: discov2
+      image: quay.io/coreos/etcd:latest
+      name: etcd2
       ports:
         - containerPort: 2379
           name: client
@@ -195,8 +194,6 @@ spec:
         - containerPort: 2380
           name: server
           protocol: TCP
-  imagePullSecrets:
-    - name: aliyun
   affinity:
     podAntiAffinity:
       requiredDuringSchedulingIgnoredDuringExecution:
@@ -205,7 +202,7 @@ spec:
               - key: app
                 operator: In
                 values:
-                  - discov
+                  - etcd
           topologyKey: "kubernetes.io/hostname"
   restartPolicy: Always
 
@@ -215,9 +212,9 @@ apiVersion: v1
 kind: Service
 metadata:
   labels:
-    discov_node: discov2
+    etcd_node: etcd2
-  name: discov2
+  name: etcd2
-  namespace: discovery
+  namespace: discov
 spec:
   ports:
     - name: client
@@ -229,7 +226,7 @@ spec:
       protocol: TCP
       targetPort: 2380
   selector:
-    discov_node: discov2
+    etcd_node: etcd2
 
 ---
 
@@ -237,30 +234,31 @@ apiVersion: v1
 kind: Pod
 metadata:
   labels:
-    app: discov
+    app: etcd
-    discov_node: discov3
+    etcd_node: etcd3
-  name: discov3
+  name: etcd3
-  namespace: discovery
+  namespace: discov
 spec:
   containers:
     - command:
         - /usr/local/bin/etcd
         - --name
-        - discov3
+        - etcd3
         - --initial-advertise-peer-urls
-        - http://discov3:2380
+        - http://etcd3:2380
         - --listen-peer-urls
         - http://0.0.0.0:2380
         - --listen-client-urls
         - http://0.0.0.0:2379
         - --advertise-client-urls
-        - http://discov3:2379
+        - http://etcd3.discov:2379
         - --initial-cluster
-        - discov0=http://discov0:2380,discov1=http://discov1:2380,discov2=http://discov2:2380,discov3=http://discov3:2380,discov4=http://discov4:2380
+        - etcd0=http://etcd0:2380,etcd1=http://etcd1:2380,etcd2=http://etcd2:2380,etcd3=http://etcd3:2380,etcd4=http://etcd4:2380
         - --initial-cluster-state
         - new
-      image: registry-vpc.cn-hangzhou.aliyuncs.com/xapp/etcd:latest
+        - --auto-compaction-retention=1
-      name: discov3
+      image: quay.io/coreos/etcd:latest
+      name: etcd3
       ports:
         - containerPort: 2379
           name: client
@@ -268,8 +266,6 @@ spec:
         - containerPort: 2380
           name: server
           protocol: TCP
-  imagePullSecrets:
-    - name: aliyun
   affinity:
     podAntiAffinity:
       requiredDuringSchedulingIgnoredDuringExecution:
@@ -278,7 +274,7 @@ spec:
               - key: app
                 operator: In
                 values:
-                  - discov
+                  - etcd
           topologyKey: "kubernetes.io/hostname"
   restartPolicy: Always
 
@@ -288,9 +284,9 @@ apiVersion: v1
 kind: Service
 metadata:
   labels:
-    discov_node: discov3
+    etcd_node: etcd3
-  name: discov3
+  name: etcd3
-  namespace: discovery
+  namespace: discov
 spec:
   ports:
     - name: client
@@ -302,7 +298,7 @@ spec:
       protocol: TCP
       targetPort: 2380
   selector:
-    discov_node: discov3
+    etcd_node: etcd3
 
 ---
 
@@ -310,30 +306,31 @@ apiVersion: v1
 kind: Pod
 metadata:
   labels:
-    app: discov
+    app: etcd
-    discov_node: discov4
+    etcd_node: etcd4
-  name: discov4
+  name: etcd4
-  namespace: discovery
+  namespace: discov
 spec:
   containers:
     - command:
         - /usr/local/bin/etcd
         - --name
-        - discov4
+        - etcd4
         - --initial-advertise-peer-urls
-        - http://discov4:2380
+        - http://etcd4:2380
         - --listen-peer-urls
         - http://0.0.0.0:2380
         - --listen-client-urls
         - http://0.0.0.0:2379
         - --advertise-client-urls
-        - http://discov4:2379
+        - http://etcd4.discov:2379
         - --initial-cluster
-        - discov0=http://discov0:2380,discov1=http://discov1:2380,discov2=http://discov2:2380,discov3=http://discov3:2380,discov4=http://discov4:2380
+        - etcd0=http://etcd0:2380,etcd1=http://etcd1:2380,etcd2=http://etcd2:2380,etcd3=http://etcd3:2380,etcd4=http://etcd4:2380
         - --initial-cluster-state
         - new
-      image: registry-vpc.cn-hangzhou.aliyuncs.com/xapp/etcd:latest
+        - --auto-compaction-retention=1
-      name: discov4
+      image: quay.io/coreos/etcd:latest
+      name: etcd4
       ports:
         - containerPort: 2379
           name: client
@@ -341,8 +338,6 @@ spec:
         - containerPort: 2380
           name: server
           protocol: TCP
-  imagePullSecrets:
-    - name: aliyun
   affinity:
     podAntiAffinity:
       requiredDuringSchedulingIgnoredDuringExecution:
@@ -351,7 +346,7 @@ spec:
               - key: app
                 operator: In
                 values:
-                  - discov
+                  - etcd
           topologyKey: "kubernetes.io/hostname"
   restartPolicy: Always
 
@@ -361,9 +356,9 @@ apiVersion: v1
 kind: Service
 metadata:
   labels:
-    discov_node: discov4
+    etcd_node: etcd4
-  name: discov4
+  name: etcd4
-  namespace: discovery
+  namespace: discov
 spec:
   ports:
     - name: client
@@ -375,4 +370,4 @@ spec:
       protocol: TCP
       targetPort: 2380
   selector:
-    discov_node: discov4
+    etcd_node: etcd4

core/discov/publisher.go

@@ -11,8 +11,10 @@ import (
 )
 
 type (
+	// PublisherOption defines the method to customize a Publisher.
 	PublisherOption func(client *Publisher)
 
+	// A Publisher can be used to publish the value to an etcd cluster on the given key.
 	Publisher struct {
 		endpoints  []string
 		key        string
@@ -26,6 +28,10 @@ type (
 	}
 )
 
+// NewPublisher returns a Publisher.
+// endpoints is the hosts of the etcd cluster.
+// key:value are a pair to be published.
+// opts are used to customize the Publisher.
 func NewPublisher(endpoints []string, key, value string, opts ...PublisherOption) *Publisher {
 	publisher := &Publisher{
 		endpoints:  endpoints,
@@ -43,6 +49,7 @@ func NewPublisher(endpoints []string, key, value string, opts ...PublisherOption
 	return publisher
 }
 
+// KeepAlive keeps key:value alive.
 func (p *Publisher) KeepAlive() error {
 	cli, err := internal.GetRegistry().GetConn(p.endpoints)
 	if err != nil {
@@ -61,14 +68,17 @@ func (p *Publisher) KeepAlive() error {
 	return p.keepAliveAsync(cli)
 }
 
+// Pause pauses the renewing of key:value.
 func (p *Publisher) Pause() {
 	p.pauseChan <- lang.Placeholder
 }
 
+// Resume resumes the renewing of key:value.
 func (p *Publisher) Resume() {
 	p.resumeChan <- lang.Placeholder
 }
 
+// Stop stops the renewing and revokes the registration.
 func (p *Publisher) Stop() {
 	p.quit.Close()
 }
@@ -135,6 +145,7 @@ func (p *Publisher) revoke(cli internal.EtcdClient) {
 	}
 }
 
+// WithId customizes a Publisher with the id.
 func WithId(id int64) PublisherOption {
 	return func(publisher *Publisher) {
 		publisher.id = id

core/discov/publisher_test.go

@@ -4,10 +4,12 @@ import (
 	"errors"
 	"sync"
 	"testing"
+	"time"
 
 	"github.com/golang/mock/gomock"
 	"github.com/stretchr/testify/assert"
 	"github.com/tal-tech/go-zero/core/discov/internal"
+	"github.com/tal-tech/go-zero/core/lang"
 	"github.com/tal-tech/go-zero/core/logx"
 	"go.etcd.io/etcd/clientv3"
 )
@@ -111,6 +113,10 @@ func TestPublisher_keepAliveAsyncQuit(t *testing.T) {
 	defer ctrl.Finish()
 	const id clientv3.LeaseID = 1
 	cli := internal.NewMockEtcdClient(ctrl)
+	cli.EXPECT().ActiveConnection()
+	cli.EXPECT().Close()
+	defer cli.Close()
+	cli.ActiveConnection()
 	restore := setMockClient(cli)
 	defer restore()
 	cli.EXPECT().Ctx().AnyTimes()
@@ -148,3 +154,16 @@ func TestPublisher_keepAliveAsyncPause(t *testing.T) {
 	pub.Pause()
 	wg.Wait()
 }
+
+func TestPublisher_Resume(t *testing.T) {
+	publisher := new(Publisher)
+	publisher.resumeChan = make(chan lang.PlaceholderType)
+	go func() {
+		publisher.Resume()
+	}()
+	go func() {
+		time.Sleep(time.Minute)
+		t.Fail()
+	}()
+	<-publisher.resumeChan
+}

core/discov/subscriber.go

@@ -13,13 +13,19 @@ type (
 		exclusive bool
 	}
 
+	// SubOption defines the method to customize a Subscriber.
 	SubOption func(opts *subOptions)
 
+	// A Subscriber is used to subscribe the given key on a etcd cluster.
 	Subscriber struct {
 		items *container
 	}
 )
 
+// NewSubscriber returns a Subscriber.
+// endpoints is the hosts of the etcd cluster.
+// key is the key to subscribe.
+// opts are used to customize the Subscriber.
 func NewSubscriber(endpoints []string, key string, opts ...SubOption) (*Subscriber, error) {
 	var subOpts subOptions
 	for _, opt := range opts {
@@ -36,15 +42,17 @@ func NewSubscriber(endpoints []string, key string, opts ...SubOption) (*Subscrib
 	return sub, nil
 }
 
+// AddListener adds listener to s.
 func (s *Subscriber) AddListener(listener func()) {
 	s.items.addListener(listener)
 }
 
+// Values returns all the subscription values.
 func (s *Subscriber) Values() []string {
 	return s.items.getValues()
 }
 
-// exclusive means that key value can only be 1:1,
+// Exclusive means that key value can only be 1:1,
 // which means later added value will remove the keys associated with the same value previously.
 func Exclusive() SubOption {
 	return func(opts *subOptions) {
@@ -100,9 +108,9 @@ func (c *container) addKv(key, value string) ([]string, bool) {
 
 	if early {
 		return previous, true
-	} else {
-		return nil, false
 	}
+
+	return nil, false
 }
 
 func (c *container) addListener(listener func()) {

core/discov/subscriber_test.go

@@ -1,6 +1,7 @@
 package discov
 
 import (
+	"sync/atomic"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -198,3 +199,18 @@ func TestContainer(t *testing.T) {
 		}
 	}
 }
+
+func TestSubscriber(t *testing.T) {
+	var opt subOptions
+	Exclusive()(&opt)
+
+	sub := new(Subscriber)
+	sub.items = newContainer(opt.exclusive)
+	var count int32
+	sub.AddListener(func() {
+		atomic.AddInt32(&count, 1)
+	})
+	sub.items.notifyChange()
+	assert.Empty(t, sub.Values())
+	assert.Equal(t, int32(1), atomic.LoadInt32(&count))
+}

core/errorx/atomicerror.go

@@ -1,21 +1,21 @@
 package errorx
 
-import "sync"
+import "sync/atomic"
 
+// AtomicError defines an atomic error.
 type AtomicError struct {
-	err  error
+	err atomic.Value // error
-	lock sync.Mutex
 }
 
+// Set sets the error.
 func (ae *AtomicError) Set(err error) {
-	ae.lock.Lock()
+	ae.err.Store(err)
-	ae.err = err
-	ae.lock.Unlock()
 }
 
+// Load returns the error.
 func (ae *AtomicError) Load() error {
-	ae.lock.Lock()
+	if v := ae.err.Load(); v != nil {
-	err := ae.err
+		return v.(error)
-	ae.lock.Unlock()
+	}
-	return err
+	return nil
 }

core/errorx/atomicerror_test.go

@@ -2,6 +2,8 @@ package errorx
 
 import (
 	"errors"
+	"sync"
+	"sync/atomic"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -19,3 +21,53 @@ func TestAtomicErrorNil(t *testing.T) {
 	var err AtomicError
 	assert.Nil(t, err.Load())
 }
+
+func BenchmarkAtomicError(b *testing.B) {
+	var aerr AtomicError
+	wg := sync.WaitGroup{}
+
+	b.Run("Load", func(b *testing.B) {
+		var done uint32
+		go func() {
+			for {
+				if atomic.LoadUint32(&done) != 0 {
+					break
+				}
+				wg.Add(1)
+				go func() {
+					aerr.Set(errDummy)
+					wg.Done()
+				}()
+			}
+		}()
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			_ = aerr.Load()
+		}
+		b.StopTimer()
+		atomic.StoreUint32(&done, 1)
+		wg.Wait()
+	})
+	b.Run("Set", func(b *testing.B) {
+		var done uint32
+		go func() {
+			for {
+				if atomic.LoadUint32(&done) != 0 {
+					break
+				}
+				wg.Add(1)
+				go func() {
+					_ = aerr.Load()
+					wg.Done()
+				}()
+			}
+		}()
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			aerr.Set(errDummy)
+		}
+		b.StopTimer()
+		atomic.StoreUint32(&done, 1)
+		wg.Wait()
+	})
+}

core/errorx/batcherror.go

@@ -3,6 +3,7 @@ package errorx
 import "bytes"
 
 type (
+	// A BatchError is an error that can hold multiple errors.
 	BatchError struct {
 		errs errorArray
 	}
@@ -10,12 +11,14 @@ type (
 	errorArray []error
 )
 
+// Add adds err to be.
 func (be *BatchError) Add(err error) {
 	if err != nil {
 		be.errs = append(be.errs, err)
 	}
 }
 
+// Err returns an error that represents all errors.
 func (be *BatchError) Err() error {
 	switch len(be.errs) {
 	case 0:
@@ -27,10 +30,12 @@ func (be *BatchError) Err() error {
 	}
 }
 
+// NotNil checks if any error inside.
 func (be *BatchError) NotNil() bool {
 	return len(be.errs) > 0
 }
 
+// Error returns a string that represents inside errors.
 func (ea errorArray) Error() string {
 	var buf bytes.Buffer
 

core/errorx/callchain.go

@@ -0,0 +1,12 @@
+package errorx
+
+// Chain runs funs one by one until an error occurred.
+func Chain(fns ...func() error) error {
+	for _, fn := range fns {
+		if err := fn(); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

core/errorx/callchain_test.go

@@ -0,0 +1,27 @@
+package errorx
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestChain(t *testing.T) {
+	errDummy := errors.New("dummy")
+	assert.Nil(t, Chain(func() error {
+		return nil
+	}, func() error {
+		return nil
+	}))
+	assert.Equal(t, errDummy, Chain(func() error {
+		return errDummy
+	}, func() error {
+		return nil
+	}))
+	assert.Equal(t, errDummy, Chain(func() error {
+		return nil
+	}, func() error {
+		return errDummy
+	}))
+}

core/executors/bulkexecutor.go

@@ -5,8 +5,12 @@ import "time"
 const defaultBulkTasks = 1000
 
 type (
+	// BulkOption defines the method to customize a BulkExecutor.
 	BulkOption func(options *bulkOptions)
 
+	// A BulkExecutor is an executor that can execute tasks on either requirement meets:
+	// 1. up to given size of tasks
+	// 2. flush interval time elapsed
 	BulkExecutor struct {
 		executor  *PeriodicalExecutor
 		container *bulkContainer
@@ -18,6 +22,7 @@ type (
 	}
 )
 
+// NewBulkExecutor returns a BulkExecutor.
 func NewBulkExecutor(execute Execute, opts ...BulkOption) *BulkExecutor {
 	options := newBulkOptions()
 	for _, opt := range opts {
@@ -36,25 +41,30 @@ func NewBulkExecutor(execute Execute, opts ...BulkOption) *BulkExecutor {
 	return executor
 }
 
+// Add adds task into be.
 func (be *BulkExecutor) Add(task interface{}) error {
 	be.executor.Add(task)
 	return nil
 }
 
+// Flush forces be to flush and execute tasks.
 func (be *BulkExecutor) Flush() {
 	be.executor.Flush()
 }
 
+// Wait waits be to done with the task execution.
 func (be *BulkExecutor) Wait() {
 	be.executor.Wait()
 }
 
+// WithBulkTasks customizes a BulkExecutor with given tasks limit.
 func WithBulkTasks(tasks int) BulkOption {
 	return func(options *bulkOptions) {
 		options.cachedTasks = tasks
 	}
 }
 
+// WithBulkInterval customizes a BulkExecutor with given flush interval.
 func WithBulkInterval(duration time.Duration) BulkOption {
 	return func(options *bulkOptions) {
 		options.flushInterval = duration

core/executors/bulkexecutor_test.go

@@ -12,14 +12,14 @@ func TestBulkExecutor(t *testing.T) {
 	var values []int
 	var lock sync.Mutex
 
-	exeutor := NewBulkExecutor(func(items []interface{}) {
+	executor := NewBulkExecutor(func(items []interface{}) {
 		lock.Lock()
 		values = append(values, len(items))
 		lock.Unlock()
 	}, WithBulkTasks(10), WithBulkInterval(time.Minute))
 
 	for i := 0; i < 50; i++ {
-		exeutor.Add(1)
+		executor.Add(1)
 		time.Sleep(time.Millisecond)
 	}
 
@@ -40,13 +40,13 @@ func TestBulkExecutorFlushInterval(t *testing.T) {
 	var wait sync.WaitGroup
 
 	wait.Add(1)
-	exeutor := NewBulkExecutor(func(items []interface{}) {
+	executor := NewBulkExecutor(func(items []interface{}) {
 		assert.Equal(t, size, len(items))
 		wait.Done()
 	}, WithBulkTasks(caches), WithBulkInterval(time.Millisecond*100))
 
 	for i := 0; i < size; i++ {
-		exeutor.Add(1)
+		executor.Add(1)
 	}
 
 	wait.Wait()
@@ -86,9 +86,7 @@ func TestBuldExecutorFlushSlowTasks(t *testing.T) {
 		time.Sleep(time.Millisecond * 100)
 		lock.Lock()
 		defer lock.Unlock()
-		for _, i := range tasks {
+		result = append(result, tasks...)
-			result = append(result, i)
-		}
 	}, WithBulkTasks(1000))
 	for i := 0; i < total; i++ {
 		assert.Nil(t, exec.Add(i))

core/executors/chunkexecutor.go

@@ -5,8 +5,12 @@ import "time"
 const defaultChunkSize = 1024 * 1024 // 1M
 
 type (
+	// ChunkOption defines the method to customize a ChunkExecutor.
 	ChunkOption func(options *chunkOptions)
 
+	// A ChunkExecutor is an executor to execute tasks when either requirement meets:
+	// 1. up to given chunk size
+	// 2. flush interval elapsed
 	ChunkExecutor struct {
 		executor  *PeriodicalExecutor
 		container *chunkContainer
@@ -18,6 +22,7 @@ type (
 	}
 )
 
+// NewChunkExecutor returns a ChunkExecutor.
 func NewChunkExecutor(execute Execute, opts ...ChunkOption) *ChunkExecutor {
 	options := newChunkOptions()
 	for _, opt := range opts {
@@ -36,6 +41,7 @@ func NewChunkExecutor(execute Execute, opts ...ChunkOption) *ChunkExecutor {
 	return executor
 }
 
+// Add adds task with given chunk size into ce.
 func (ce *ChunkExecutor) Add(task interface{}, size int) error {
 	ce.executor.Add(chunk{
 		val:  task,
@@ -44,20 +50,24 @@ func (ce *ChunkExecutor) Add(task interface{}, size int) error {
 	return nil
 }
 
+// Flush forces ce to flush and execute tasks.
 func (ce *ChunkExecutor) Flush() {
 	ce.executor.Flush()
 }
 
+// Wait waits the execution to be done.
 func (ce *ChunkExecutor) Wait() {
 	ce.executor.Wait()
 }
 
+// WithChunkBytes customizes a ChunkExecutor with the given chunk size.
 func WithChunkBytes(size int) ChunkOption {
 	return func(options *chunkOptions) {
 		options.chunkSize = size
 	}
 }
 
+// WithFlushInterval customizes a ChunkExecutor with the given flush interval.
 func WithFlushInterval(duration time.Duration) ChunkOption {
 	return func(options *chunkOptions) {
 		options.flushInterval = duration

core/executors/chunkexecutor_test.go

@@ -12,14 +12,14 @@ func TestChunkExecutor(t *testing.T) {
 	var values []int
 	var lock sync.Mutex
 
-	exeutor := NewChunkExecutor(func(items []interface{}) {
+	executor := NewChunkExecutor(func(items []interface{}) {
 		lock.Lock()
 		values = append(values, len(items))
 		lock.Unlock()
 	}, WithChunkBytes(10), WithFlushInterval(time.Minute))
 
 	for i := 0; i < 50; i++ {
-		exeutor.Add(1, 1)
+		executor.Add(1, 1)
 		time.Sleep(time.Millisecond)
 	}
 
@@ -40,13 +40,13 @@ func TestChunkExecutorFlushInterval(t *testing.T) {
 	var wait sync.WaitGroup
 
 	wait.Add(1)
-	exeutor := NewChunkExecutor(func(items []interface{}) {
+	executor := NewChunkExecutor(func(items []interface{}) {
 		assert.Equal(t, size, len(items))
 		wait.Done()
 	}, WithChunkBytes(caches), WithFlushInterval(time.Millisecond*100))
 
 	for i := 0; i < size; i++ {
-		exeutor.Add(1, 1)
+		executor.Add(1, 1)
 	}
 
 	wait.Wait()

core/executors/delayexecutor.go

@@ -7,6 +7,7 @@ import (
 	"github.com/tal-tech/go-zero/core/threading"
 )
 
+// A DelayExecutor delays a tasks on given delay interval.
 type DelayExecutor struct {
 	fn        func()
 	delay     time.Duration
@@ -14,6 +15,7 @@ type DelayExecutor struct {
 	lock      sync.Mutex
 }
 
+// NewDelayExecutor returns a DelayExecutor with given fn and delay.
 func NewDelayExecutor(fn func(), delay time.Duration) *DelayExecutor {
 	return &DelayExecutor{
 		fn:    fn,
@@ -21,6 +23,7 @@ func NewDelayExecutor(fn func(), delay time.Duration) *DelayExecutor {
 	}
 }
 
+// Trigger triggers the task to be executed after given delay, safe to trigger more than once.
 func (de *DelayExecutor) Trigger() {
 	de.lock.Lock()
 	defer de.lock.Unlock()

core/executors/lessexecutor.go

@@ -7,11 +7,13 @@ import (
 	"github.com/tal-tech/go-zero/core/timex"
 )
 
+// A LessExecutor is an executor to limit execution once within given time interval.
 type LessExecutor struct {
 	threshold time.Duration
 	lastTime  *syncx.AtomicDuration
 }
 
+// NewLessExecutor returns a LessExecutor with given threshold as time interval.
 func NewLessExecutor(threshold time.Duration) *LessExecutor {
 	return &LessExecutor{
 		threshold: threshold,
@@ -19,6 +21,8 @@ func NewLessExecutor(threshold time.Duration) *LessExecutor {
 	}
 }
 
+// DoOrDiscard executes or discards the task depends on if
+// another task was executed within the time interval.
 func (le *LessExecutor) DoOrDiscard(execute func()) bool {
 	now := timex.Now()
 	lastTime := le.lastTime.Load()

core/executors/periodicalexecutor.go

@@ -3,8 +3,10 @@ package executors
 import (
 	"reflect"
 	"sync"
+	"sync/atomic"
 	"time"
 
+	"github.com/tal-tech/go-zero/core/lang"
 	"github.com/tal-tech/go-zero/core/proc"
 	"github.com/tal-tech/go-zero/core/syncx"
 	"github.com/tal-tech/go-zero/core/threading"
@@ -14,7 +16,7 @@ import (
 const idleRound = 10
 
 type (
-	// A type that satisfies executors.TaskContainer can be used as the underlying
+	// TaskContainer interface defines a type that can be used as the underlying
 	// container that used to do periodical executions.
 	TaskContainer interface {
 		// AddTask adds the task into the container.
@@ -26,27 +28,32 @@ type (
 		RemoveAll() interface{}
 	}
 
+	// A PeriodicalExecutor is an executor that periodically execute tasks.
 	PeriodicalExecutor struct {
 		commander chan interface{}
 		interval  time.Duration
 		container TaskContainer
 		waitGroup sync.WaitGroup
 		// avoid race condition on waitGroup when calling wg.Add/Done/Wait(...)
-		wgBarrier syncx.Barrier
+		wgBarrier   syncx.Barrier
-		guarded   bool
+		confirmChan chan lang.PlaceholderType
-		newTicker func(duration time.Duration) timex.Ticker
+		inflight    int32
-		lock      sync.Mutex
+		guarded     bool
+		newTicker   func(duration time.Duration) timex.Ticker
+		lock        sync.Mutex
 	}
 )
 
+// NewPeriodicalExecutor returns a PeriodicalExecutor with given interval and container.
 func NewPeriodicalExecutor(interval time.Duration, container TaskContainer) *PeriodicalExecutor {
 	executor := &PeriodicalExecutor{
 		// buffer 1 to let the caller go quickly
-		commander: make(chan interface{}, 1),
+		commander:   make(chan interface{}, 1),
-		interval:  interval,
+		interval:    interval,
-		container: container,
+		container:   container,
+		confirmChan: make(chan lang.PlaceholderType),
 		newTicker: func(d time.Duration) timex.Ticker {
-			return timex.NewTicker(interval)
+			return timex.NewTicker(d)
 		},
 	}
 	proc.AddShutdownListener(func() {
@@ -56,13 +63,17 @@ func NewPeriodicalExecutor(interval time.Duration, container TaskContainer) *Per
 	return executor
 }
 
+// Add adds tasks into pe.
 func (pe *PeriodicalExecutor) Add(task interface{}) {
 	if vals, ok := pe.addAndCheck(task); ok {
 		pe.commander <- vals
+		<-pe.confirmChan
 	}
 }
 
+// Flush forces pe to execute tasks.
 func (pe *PeriodicalExecutor) Flush() bool {
+	pe.enterExecution()
 	return pe.executeTasks(func() interface{} {
 		pe.lock.Lock()
 		defer pe.lock.Unlock()
@@ -70,13 +81,16 @@ func (pe *PeriodicalExecutor) Flush() bool {
 	}())
 }
 
+// Sync lets caller to run fn thread-safe with pe, especially for the underlying container.
 func (pe *PeriodicalExecutor) Sync(fn func()) {
 	pe.lock.Lock()
 	defer pe.lock.Unlock()
 	fn()
 }
 
+// Wait waits the execution to be done.
 func (pe *PeriodicalExecutor) Wait() {
+	pe.Flush()
 	pe.wgBarrier.Guard(func() {
 		pe.waitGroup.Wait()
 	})
@@ -85,18 +99,16 @@ func (pe *PeriodicalExecutor) Wait() {
 func (pe *PeriodicalExecutor) addAndCheck(task interface{}) (interface{}, bool) {
 	pe.lock.Lock()
 	defer func() {
-		var start bool
 		if !pe.guarded {
 			pe.guarded = true
-			start = true
+			// defer to unlock quickly
+			defer pe.backgroundFlush()
 		}
 		pe.lock.Unlock()
-		if start {
-			pe.backgroundFlush()
-		}
 	}()
 
 	if pe.container.AddTask(task) {
+		atomic.AddInt32(&pe.inflight, 1)
 		return pe.container.RemoveAll(), true
 	}
 
@@ -105,6 +117,9 @@ func (pe *PeriodicalExecutor) addAndCheck(task interface{}) (interface{}, bool)
 
 func (pe *PeriodicalExecutor) backgroundFlush() {
 	threading.GoSafe(func() {
+		// flush before quit goroutine to avoid missing tasks
+		defer pe.Flush()
+
 		ticker := pe.newTicker(pe.interval)
 		defer ticker.Stop()
 
@@ -114,6 +129,9 @@ func (pe *PeriodicalExecutor) backgroundFlush() {
 			select {
 			case vals := <-pe.commander:
 				commanded = true
+				atomic.AddInt32(&pe.inflight, -1)
+				pe.enterExecution()
+				pe.confirmChan <- lang.Placeholder
 				pe.executeTasks(vals)
 				last = timex.Now()
 			case <-ticker.Chan():
@@ -121,13 +139,7 @@ func (pe *PeriodicalExecutor) backgroundFlush() {
 					commanded = false
 				} else if pe.Flush() {
 					last = timex.Now()
-				} else if timex.Since(last) > pe.interval*idleRound {
+				} else if pe.shallQuit(last) {
-					pe.lock.Lock()
-					pe.guarded = false
-					pe.lock.Unlock()
-
-					// flush again to avoid missing tasks
-					pe.Flush()
 					return
 				}
 			}
@@ -135,11 +147,18 @@ func (pe *PeriodicalExecutor) backgroundFlush() {
 	})
 }
 
-func (pe *PeriodicalExecutor) executeTasks(tasks interface{}) bool {
+func (pe *PeriodicalExecutor) doneExecution() {
+	pe.waitGroup.Done()
+}
+
+func (pe *PeriodicalExecutor) enterExecution() {
 	pe.wgBarrier.Guard(func() {
 		pe.waitGroup.Add(1)
 	})
-	defer pe.waitGroup.Done()
+}
+
+func (pe *PeriodicalExecutor) executeTasks(tasks interface{}) bool {
+	defer pe.doneExecution()
 
 	ok := pe.hasTasks(tasks)
 	if ok {
@@ -163,3 +182,19 @@ func (pe *PeriodicalExecutor) hasTasks(tasks interface{}) bool {
 		return true
 	}
 }
+
+func (pe *PeriodicalExecutor) shallQuit(last time.Duration) (stop bool) {
+	if timex.Since(last) <= pe.interval*idleRound {
+		return
+	}
+
+	// checking pe.inflight and setting pe.guarded should be locked together
+	pe.lock.Lock()
+	if atomic.LoadInt32(&pe.inflight) == 0 {
+		pe.guarded = false
+		stop = true
+	}
+	pe.lock.Unlock()
+
+	return
+}

core/executors/periodicalexecutor_test.go

@@ -106,6 +106,60 @@ func TestPeriodicalExecutor_Bulk(t *testing.T) {
 	lock.Unlock()
 }
 
+func TestPeriodicalExecutor_Wait(t *testing.T) {
+	var lock sync.Mutex
+	executer := NewBulkExecutor(func(tasks []interface{}) {
+		lock.Lock()
+		defer lock.Unlock()
+		time.Sleep(10 * time.Millisecond)
+	}, WithBulkTasks(1), WithBulkInterval(time.Second))
+	for i := 0; i < 10; i++ {
+		executer.Add(1)
+	}
+	executer.Flush()
+	executer.Wait()
+}
+
+func TestPeriodicalExecutor_WaitFast(t *testing.T) {
+	const total = 3
+	var cnt int
+	var lock sync.Mutex
+	executer := NewBulkExecutor(func(tasks []interface{}) {
+		defer func() {
+			cnt++
+		}()
+		lock.Lock()
+		defer lock.Unlock()
+		time.Sleep(10 * time.Millisecond)
+	}, WithBulkTasks(1), WithBulkInterval(10*time.Millisecond))
+	for i := 0; i < total; i++ {
+		executer.Add(2)
+	}
+	executer.Flush()
+	executer.Wait()
+	assert.Equal(t, total, cnt)
+}
+
+func TestPeriodicalExecutor_Deadlock(t *testing.T) {
+	executor := NewBulkExecutor(func(tasks []interface{}) {
+	}, WithBulkTasks(1), WithBulkInterval(time.Millisecond))
+	for i := 0; i < 1e5; i++ {
+		executor.Add(1)
+	}
+}
+
+func TestPeriodicalExecutor_hasTasks(t *testing.T) {
+	ticker := timex.NewFakeTicker()
+	defer ticker.Stop()
+
+	exec := NewPeriodicalExecutor(time.Millisecond, newContainer(time.Millisecond, nil))
+	exec.newTicker = func(d time.Duration) timex.Ticker {
+		return ticker
+	}
+	assert.False(t, exec.hasTasks(nil))
+	assert.True(t, exec.hasTasks(1))
+}
+
 // go test -benchtime 10s -bench .
 func BenchmarkExecutor(b *testing.B) {
 	b.ReportAllocs()

core/executors/vars.go

@@ -4,4 +4,5 @@ import "time"
 
 const defaultFlushInterval = time.Second
 
+// Execute defines the method to execute tasks.
 type Execute func(tasks []interface{})

core/filex/file.go

@@ -7,6 +7,7 @@ import (
 
 const bufSize = 1024
 
+// FirstLine returns the first line of the file.
 func FirstLine(filename string) (string, error) {
 	file, err := os.Open(filename)
 	if err != nil {
@@ -17,6 +18,7 @@ func FirstLine(filename string) (string, error) {
 	return firstLine(file)
 }
 
+// LastLine returns the last line of the file.
 func LastLine(filename string) (string, error) {
 	file, err := os.Open(filename)
 	if err != nil {
@@ -69,11 +71,11 @@ func lastLine(filename string, file *os.File) (string, error) {
 
 		if buf[n-1] == '\n' {
 			buf = buf[:n-1]
-			n -= 1
+			n--
 		} else {
 			buf = buf[:n]
 		}
-		for n -= 1; n >= 0; n-- {
+		for n--; n >= 0; n-- {
 			if buf[n] == '\n' {
 				return string(append(buf[n+1:], last...)), nil
 			}

core/filex/file_test.go

@@ -4,9 +4,8 @@ import (
 	"os"
 	"testing"
 
-	"github.com/tal-tech/go-zero/core/fs"
-
 	"github.com/stretchr/testify/assert"
+	"github.com/tal-tech/go-zero/core/fs"
 )
 
 const (
@@ -15,34 +14,34 @@ const (
 	text          = `first line
 Cum sociis natoque penatibus et magnis dis parturient. Phasellus laoreet lorem vel dolor tempus vehicula. Vivamus sagittis lacus vel augue laoreet rutrum faucibus. Integer legentibus erat a ante historiarum dapibus.
 Quisque ut dolor gravida, placerat libero vel, euismod. Quam temere in vitiis, legem sancimus haerentia. Qui ipsorum lingua Celtae, nostra Galli appellantur. Quis aute iure reprehenderit in voluptate velit esse. Fabio vel iudice vincam, sunt in culpa qui officia. Cras mattis iudicium purus sit amet fermentum.
-Quo usque tandem abutere, Catilina, patientia nostra? Gallia est omnis divisa in partes tres, quarum. Quam diu etiam furor iste tuus nos eludet? Quid securi etiam tamquam eu fugiat nulla pariatur. Curabitur blandit tempus ardua ridiculus sed magna.
+Quo usque tandem abutere, Catilina, patientia nostra? Gallia est omnis divisa in partes tres, quarum. Quam diu etiam furor iste tuus nos eludet? Quid securi etiam tamquam eu fugiat nulla pariatur. Curabitur blandit tempus ardua ridiculous sed magna.
 Magna pars studiorum, prodita quaerimus. Cum ceteris in veneratione tui montes, nascetur mus. Morbi odio eros, volutpat ut pharetra vitae, lobortis sed nibh. Plura mihi bona sunt, inclinet, amari petere vellent. Idque Caesaris facere voluntate liceret: sese habere. Tu quoque, Brute, fili mi, nihil timor populi, nihil!
 Tityre, tu patulae recubans sub tegmine fagi dolor. Inmensae subtilitatis, obscuris et malesuada fames. Quae vero auctorem tractata ab fiducia dicuntur.
 Cum sociis natoque penatibus et magnis dis parturient. Phasellus laoreet lorem vel dolor tempus vehicula. Vivamus sagittis lacus vel augue laoreet rutrum faucibus. Integer legentibus erat a ante historiarum dapibus.
 Quisque ut dolor gravida, placerat libero vel, euismod. Quam temere in vitiis, legem sancimus haerentia. Qui ipsorum lingua Celtae, nostra Galli appellantur. Quis aute iure reprehenderit in voluptate velit esse. Fabio vel iudice vincam, sunt in culpa qui officia. Cras mattis iudicium purus sit amet fermentum.
-Quo usque tandem abutere, Catilina, patientia nostra? Gallia est omnis divisa in partes tres, quarum. Quam diu etiam furor iste tuus nos eludet? Quid securi etiam tamquam eu fugiat nulla pariatur. Curabitur blandit tempus ardua ridiculus sed magna.
+Quo usque tandem abutere, Catilina, patientia nostra? Gallia est omnis divisa in partes tres, quarum. Quam diu etiam furor iste tuus nos eludet? Quid securi etiam tamquam eu fugiat nulla pariatur. Curabitur blandit tempus ardua ridiculous sed magna.
 Magna pars studiorum, prodita quaerimus. Cum ceteris in veneratione tui montes, nascetur mus. Morbi odio eros, volutpat ut pharetra vitae, lobortis sed nibh. Plura mihi bona sunt, inclinet, amari petere vellent. Idque Caesaris facere voluntate liceret: sese habere. Tu quoque, Brute, fili mi, nihil timor populi, nihil!
 Tityre, tu patulae recubans sub tegmine fagi dolor. Inmensae subtilitatis, obscuris et malesuada fames. Quae vero auctorem tractata ab fiducia dicuntur.
 Cum sociis natoque penatibus et magnis dis parturient. Phasellus laoreet lorem vel dolor tempus vehicula. Vivamus sagittis lacus vel augue laoreet rutrum faucibus. Integer legentibus erat a ante historiarum dapibus.
 Quisque ut dolor gravida, placerat libero vel, euismod. Quam temere in vitiis, legem sancimus haerentia. Qui ipsorum lingua Celtae, nostra Galli appellantur. Quis aute iure reprehenderit in voluptate velit esse. Fabio vel iudice vincam, sunt in culpa qui officia. Cras mattis iudicium purus sit amet fermentum.
-Quo usque tandem abutere, Catilina, patientia nostra? Gallia est omnis divisa in partes tres, quarum. Quam diu etiam furor iste tuus nos eludet? Quid securi etiam tamquam eu fugiat nulla pariatur. Curabitur blandit tempus ardua ridiculus sed magna.
+Quo usque tandem abutere, Catilina, patientia nostra? Gallia est omnis divisa in partes tres, quarum. Quam diu etiam furor iste tuus nos eludet? Quid securi etiam tamquam eu fugiat nulla pariatur. Curabitur blandit tempus ardua ridiculous sed magna.
 Magna pars studiorum, prodita quaerimus. Cum ceteris in veneratione tui montes, nascetur mus. Morbi odio eros, volutpat ut pharetra vitae, lobortis sed nibh. Plura mihi bona sunt, inclinet, amari petere vellent. Idque Caesaris facere voluntate liceret: sese habere. Tu quoque, Brute, fili mi, nihil timor populi, nihil!
 Tityre, tu patulae recubans sub tegmine fagi dolor. Inmensae subtilitatis, obscuris et malesuada fames. Quae vero auctorem tractata ab fiducia dicuntur.
 ` + longLine
 	textWithLastNewline = `first line
 Cum sociis natoque penatibus et magnis dis parturient. Phasellus laoreet lorem vel dolor tempus vehicula. Vivamus sagittis lacus vel augue laoreet rutrum faucibus. Integer legentibus erat a ante historiarum dapibus.
 Quisque ut dolor gravida, placerat libero vel, euismod. Quam temere in vitiis, legem sancimus haerentia. Qui ipsorum lingua Celtae, nostra Galli appellantur. Quis aute iure reprehenderit in voluptate velit esse. Fabio vel iudice vincam, sunt in culpa qui officia. Cras mattis iudicium purus sit amet fermentum.
-Quo usque tandem abutere, Catilina, patientia nostra? Gallia est omnis divisa in partes tres, quarum. Quam diu etiam furor iste tuus nos eludet? Quid securi etiam tamquam eu fugiat nulla pariatur. Curabitur blandit tempus ardua ridiculus sed magna.
+Quo usque tandem abutere, Catilina, patientia nostra? Gallia est omnis divisa in partes tres, quarum. Quam diu etiam furor iste tuus nos eludet? Quid securi etiam tamquam eu fugiat nulla pariatur. Curabitur blandit tempus ardua ridiculous sed magna.
 Magna pars studiorum, prodita quaerimus. Cum ceteris in veneratione tui montes, nascetur mus. Morbi odio eros, volutpat ut pharetra vitae, lobortis sed nibh. Plura mihi bona sunt, inclinet, amari petere vellent. Idque Caesaris facere voluntate liceret: sese habere. Tu quoque, Brute, fili mi, nihil timor populi, nihil!
 Tityre, tu patulae recubans sub tegmine fagi dolor. Inmensae subtilitatis, obscuris et malesuada fames. Quae vero auctorem tractata ab fiducia dicuntur.
 Cum sociis natoque penatibus et magnis dis parturient. Phasellus laoreet lorem vel dolor tempus vehicula. Vivamus sagittis lacus vel augue laoreet rutrum faucibus. Integer legentibus erat a ante historiarum dapibus.
 Quisque ut dolor gravida, placerat libero vel, euismod. Quam temere in vitiis, legem sancimus haerentia. Qui ipsorum lingua Celtae, nostra Galli appellantur. Quis aute iure reprehenderit in voluptate velit esse. Fabio vel iudice vincam, sunt in culpa qui officia. Cras mattis iudicium purus sit amet fermentum.
-Quo usque tandem abutere, Catilina, patientia nostra? Gallia est omnis divisa in partes tres, quarum. Quam diu etiam furor iste tuus nos eludet? Quid securi etiam tamquam eu fugiat nulla pariatur. Curabitur blandit tempus ardua ridiculus sed magna.
+Quo usque tandem abutere, Catilina, patientia nostra? Gallia est omnis divisa in partes tres, quarum. Quam diu etiam furor iste tuus nos eludet? Quid securi etiam tamquam eu fugiat nulla pariatur. Curabitur blandit tempus ardua ridiculous sed magna.
 Magna pars studiorum, prodita quaerimus. Cum ceteris in veneratione tui montes, nascetur mus. Morbi odio eros, volutpat ut pharetra vitae, lobortis sed nibh. Plura mihi bona sunt, inclinet, amari petere vellent. Idque Caesaris facere voluntate liceret: sese habere. Tu quoque, Brute, fili mi, nihil timor populi, nihil!
 Tityre, tu patulae recubans sub tegmine fagi dolor. Inmensae subtilitatis, obscuris et malesuada fames. Quae vero auctorem tractata ab fiducia dicuntur.
 Cum sociis natoque penatibus et magnis dis parturient. Phasellus laoreet lorem vel dolor tempus vehicula. Vivamus sagittis lacus vel augue laoreet rutrum faucibus. Integer legentibus erat a ante historiarum dapibus.
 Quisque ut dolor gravida, placerat libero vel, euismod. Quam temere in vitiis, legem sancimus haerentia. Qui ipsorum lingua Celtae, nostra Galli appellantur. Quis aute iure reprehenderit in voluptate velit esse. Fabio vel iudice vincam, sunt in culpa qui officia. Cras mattis iudicium purus sit amet fermentum.
-Quo usque tandem abutere, Catilina, patientia nostra? Gallia est omnis divisa in partes tres, quarum. Quam diu etiam furor iste tuus nos eludet? Quid securi etiam tamquam eu fugiat nulla pariatur. Curabitur blandit tempus ardua ridiculus sed magna.
+Quo usque tandem abutere, Catilina, patientia nostra? Gallia est omnis divisa in partes tres, quarum. Quam diu etiam furor iste tuus nos eludet? Quid securi etiam tamquam eu fugiat nulla pariatur. Curabitur blandit tempus ardua ridiculous sed magna.
 Magna pars studiorum, prodita quaerimus. Cum ceteris in veneratione tui montes, nascetur mus. Morbi odio eros, volutpat ut pharetra vitae, lobortis sed nibh. Plura mihi bona sunt, inclinet, amari petere vellent. Idque Caesaris facere voluntate liceret: sese habere. Tu quoque, Brute, fili mi, nihil timor populi, nihil!
 Tityre, tu patulae recubans sub tegmine fagi dolor. Inmensae subtilitatis, obscuris et malesuada fames. Quae vero auctorem tractata ab fiducia dicuntur.
 ` + longLine + "\n"

core/filex/lookup.go

@@ -5,12 +5,15 @@ import (
 	"os"
 )
 
+// OffsetRange represents a content block of a file.
 type OffsetRange struct {
 	File  string
 	Start int64
 	Stop  int64
 }
 
+// SplitLineChunks splits file into chunks.
+// The whole line are guaranteed to be split in the same chunk.
 func SplitLineChunks(filename string, chunks int) ([]OffsetRange, error) {
 	info, err := os.Stat(filename)
 	if err != nil {

core/filex/progressscanner.go

@@ -3,8 +3,11 @@ package filex
 import "gopkg.in/cheggaaa/pb.v1"
 
 type (
+	// A Scanner is used to read lines.
 	Scanner interface {
+		// Scan checks if has remaining to read.
 		Scan() bool
+		// Text returns next line.
 		Text() string
 	}
 
@@ -14,6 +17,7 @@ type (
 	}
 )
 
+// NewProgressScanner returns a Scanner with progress indicator.
 func NewProgressScanner(scanner Scanner, bar *pb.ProgressBar) Scanner {
 	return &progressScanner{
 		Scanner: scanner,

core/filex/rangereader.go

@@ -5,12 +5,14 @@ import (
 	"os"
 )
 
+// A RangeReader is used to read a range of content from a file.
 type RangeReader struct {
 	file  *os.File
 	start int64
 	stop  int64
 }
 
+// NewRangeReader returns a RangeReader, which will read the range of content from file.
 func NewRangeReader(file *os.File, start, stop int64) *RangeReader {
 	return &RangeReader{
 		file:  file,
@@ -19,6 +21,7 @@ func NewRangeReader(file *os.File, start, stop int64) *RangeReader {
 	}
 }
 
+// Read reads the range of content into p.
 func (rr *RangeReader) Read(p []byte) (n int, err error) {
 	stat, err := rr.file.Stat()
 	if err != nil {

core/fs/files.go

@@ -7,6 +7,7 @@ import (
 	"syscall"
 )
 
+// CloseOnExec makes sure closing the file on process forking.
 func CloseOnExec(file *os.File) {
 	if file != nil {
 		syscall.CloseOnExec(int(file.Fd()))

core/fx/parallel.go

@@ -2,6 +2,7 @@ package fx
 
 import "github.com/tal-tech/go-zero/core/threading"
 
+// Parallel runs fns parallelly and waits for done.
 func Parallel(fns ...func()) {
 	group := threading.NewRoutineGroup()
 	for _, fn := range fns {

core/fx/retry.go

@@ -5,6 +5,7 @@ import "github.com/tal-tech/go-zero/core/errorx"
 const defaultRetryTimes = 3
 
 type (
+	// RetryOption defines the method to customize DoWithRetry.
 	RetryOption func(*retryOptions)
 
 	retryOptions struct {
@@ -12,8 +13,9 @@ type (
 	}
 )
 
-func DoWithRetries(fn func() error, opts ...RetryOption) error {
+// DoWithRetry runs fn, and retries if failed. Default to retry 3 times.
-	var options = newRetryOptions()
+func DoWithRetry(fn func() error, opts ...RetryOption) error {
+	options := newRetryOptions()
 	for _, opt := range opts {
 		opt(options)
 	}
@@ -30,7 +32,8 @@ func DoWithRetries(fn func() error, opts ...RetryOption) error {
 	return berr.Err()
 }
 
-func WithRetries(times int) RetryOption {
+// WithRetry customize a DoWithRetry call with given retry times.
+func WithRetry(times int) RetryOption {
 	return func(options *retryOptions) {
 		options.times = times
 	}

core/fx/retry_test.go

@@ -8,12 +8,12 @@ import (
 )
 
 func TestRetry(t *testing.T) {
-	assert.NotNil(t, DoWithRetries(func() error {
+	assert.NotNil(t, DoWithRetry(func() error {
 		return errors.New("any")
 	}))
 
 	var times int
-	assert.Nil(t, DoWithRetries(func() error {
+	assert.Nil(t, DoWithRetry(func() error {
 		times++
 		if times == defaultRetryTimes {
 			return nil
@@ -22,7 +22,7 @@ func TestRetry(t *testing.T) {
 	}))
 
 	times = 0
-	assert.NotNil(t, DoWithRetries(func() error {
+	assert.NotNil(t, DoWithRetry(func() error {
 		times++
 		if times == defaultRetryTimes+1 {
 			return nil
@@ -30,13 +30,13 @@ func TestRetry(t *testing.T) {
 		return errors.New("any")
 	}))
 
-	var total = 2 * defaultRetryTimes
+	total := 2 * defaultRetryTimes
 	times = 0
-	assert.Nil(t, DoWithRetries(func() error {
+	assert.Nil(t, DoWithRetry(func() error {
 		times++
 		if times == total {
 			return nil
 		}
 		return errors.New("any")
-	}, WithRetries(total)))
+	}, WithRetry(total)))
 }

core/fx/stream.go

@@ -20,18 +20,30 @@ type (
 		workers          int
 	}
 
-	FilterFunc   func(item interface{}) bool
+	// FilterFunc defines the method to filter a Stream.
-	ForAllFunc   func(pipe <-chan interface{})
+	FilterFunc func(item interface{}) bool
-	ForEachFunc  func(item interface{})
+	// ForAllFunc defines the method to handle all elements in a Stream.
+	ForAllFunc func(pipe <-chan interface{})
+	// ForEachFunc defines the method to handle each element in a Stream.
+	ForEachFunc func(item interface{})
+	// GenerateFunc defines the method to send elements into a Stream.
 	GenerateFunc func(source chan<- interface{})
-	KeyFunc      func(item interface{}) interface{}
+	// KeyFunc defines the method to generate keys for the elements in a Stream.
-	LessFunc     func(a, b interface{}) bool
+	KeyFunc func(item interface{}) interface{}
-	MapFunc      func(item interface{}) interface{}
+	// LessFunc defines the method to compare the elements in a Stream.
-	Option       func(opts *rxOptions)
+	LessFunc func(a, b interface{}) bool
+	// MapFunc defines the method to map each element to another object in a Stream.
+	MapFunc func(item interface{}) interface{}
+	// Option defines the method to customize a Stream.
+	Option func(opts *rxOptions)
+	// ParallelFunc defines the method to handle elements parallelly.
 	ParallelFunc func(item interface{})
-	ReduceFunc   func(pipe <-chan interface{}) (interface{}, error)
+	// ReduceFunc defines the method to reduce all the elements in a Stream.
-	WalkFunc     func(item interface{}, pipe chan<- interface{})
+	ReduceFunc func(pipe <-chan interface{}) (interface{}, error)
+	// WalkFunc defines the method to walk through all the elements in a Stream.
+	WalkFunc func(item interface{}, pipe chan<- interface{})
 
+	// A Stream is a stream that can be used to do stream processing.
 	Stream struct {
 		source <-chan interface{}
 	}
@@ -49,7 +61,7 @@ func From(generate GenerateFunc) Stream {
 	return Range(source)
 }
 
-// Just converts the given arbitary items to a Stream.
+// Just converts the given arbitrary items to a Stream.
 func Just(items ...interface{}) Stream {
 	source := make(chan interface{}, len(items))
 	for _, item := range items {
@@ -68,6 +80,7 @@ func Range(source <-chan interface{}) Stream {
 }
 
 // Buffer buffers the items into a queue with size n.
+// It can balance the producer and the consumer if their processing throughput don't match.
 func (p Stream) Buffer(n int) Stream {
 	if n < 0 {
 		n = 0
@@ -84,6 +97,14 @@ func (p Stream) Buffer(n int) Stream {
 	return Range(source)
 }
 
+// Count counts the number of elements in the result.
+func (p Stream) Count() (count int) {
+	for range p.source {
+		count++
+	}
+	return
+}
+
 // Distinct removes the duplicated items base on the given KeyFunc.
 func (p Stream) Distinct(fn KeyFunc) Stream {
 	source := make(chan interface{})
@@ -150,7 +171,12 @@ func (p Stream) Group(fn KeyFunc) Stream {
 	return Range(source)
 }
 
+// Head returns the first n elements in p.
 func (p Stream) Head(n int64) Stream {
+	if n < 1 {
+		panic("n must be greater than 0")
+	}
+
 	source := make(chan interface{})
 
 	go func() {
@@ -174,7 +200,7 @@ func (p Stream) Head(n int64) Stream {
 	return Range(source)
 }
 
-// Maps converts each item to another corresponding item, which means it's a 1:1 model.
+// Map converts each item to another corresponding item, which means it's a 1:1 model.
 func (p Stream) Map(fn MapFunc, opts ...Option) Stream {
 	return p.Walk(func(item interface{}, pipe chan<- interface{}) {
 		pipe <- fn(item)
@@ -195,7 +221,7 @@ func (p Stream) Merge() Stream {
 	return Range(source)
 }
 
-// Parallel applies the given ParallenFunc to each item concurrently with given number of workers.
+// Parallel applies the given ParallelFunc to each item concurrently with given number of workers.
 func (p Stream) Parallel(fn ParallelFunc, opts ...Option) {
 	p.Walk(func(item interface{}, pipe chan<- interface{}) {
 		fn(item)
@@ -235,7 +261,38 @@ func (p Stream) Sort(less LessFunc) Stream {
 	return Just(items...)
 }
 
+// Split splits the elements into chunk with size up to n,
+// might be less than n on tailing elements.
+func (p Stream) Split(n int) Stream {
+	if n < 1 {
+		panic("n should be greater than 0")
+	}
+
+	source := make(chan interface{})
+	go func() {
+		var chunk []interface{}
+		for item := range p.source {
+			chunk = append(chunk, item)
+			if len(chunk) == n {
+				source <- chunk
+				chunk = nil
+			}
+		}
+		if chunk != nil {
+			source <- chunk
+		}
+		close(source)
+	}()
+
+	return Range(source)
+}
+
+// Tail returns the last n elements in p.
 func (p Stream) Tail(n int64) Stream {
+	if n < 1 {
+		panic("n should be greater than 0")
+	}
+
 	source := make(chan interface{})
 
 	go func() {
@@ -257,9 +314,9 @@ func (p Stream) Walk(fn WalkFunc, opts ...Option) Stream {
 	option := buildOptions(opts...)
 	if option.unlimitedWorkers {
 		return p.walkUnlimited(fn, option)
-	} else {
-		return p.walkLimited(fn, option)
 	}
+
+	return p.walkLimited(fn, option)
 }
 
 func (p Stream) walkLimited(fn WalkFunc, option *rxOptions) Stream {

core/fx/stream_test.go

@@ -49,6 +49,36 @@ func TestBufferNegative(t *testing.T) {
 	assert.Equal(t, 10, result)
 }
 
+func TestCount(t *testing.T) {
+	tests := []struct {
+		name     string
+		elements []interface{}
+	}{
+		{
+			name: "no elements with nil",
+		},
+		{
+			name:     "no elements",
+			elements: []interface{}{},
+		},
+		{
+			name:     "1 element",
+			elements: []interface{}{1},
+		},
+		{
+			name:     "multiple elements",
+			elements: []interface{}{1, 2, 3},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			val := Just(test.elements...).Count()
+			assert.Equal(t, len(test.elements), val)
+		})
+	}
+}
+
 func TestDone(t *testing.T) {
 	var count int32
 	Just(1, 2, 3).Walk(func(item interface{}, pipe chan<- interface{}) {
@@ -139,6 +169,14 @@ func TestHead(t *testing.T) {
 	assert.Equal(t, 3, result)
 }
 
+func TestHeadZero(t *testing.T) {
+	assert.Panics(t, func() {
+		Just(1, 2, 3, 4).Head(0).Reduce(func(pipe <-chan interface{}) (interface{}, error) {
+			return nil, nil
+		})
+	})
+}
+
 func TestHeadMore(t *testing.T) {
 	var result int
 	Just(1, 2, 3, 4).Head(6).Reduce(func(pipe <-chan interface{}) (interface{}, error) {
@@ -245,6 +283,22 @@ func TestSort(t *testing.T) {
 	})
 }
 
+func TestSplit(t *testing.T) {
+	assert.Panics(t, func() {
+		Just(1, 2, 3, 4, 5, 6, 7, 8, 9, 10).Split(0).Done()
+	})
+	var chunks [][]interface{}
+	Just(1, 2, 3, 4, 5, 6, 7, 8, 9, 10).Split(4).ForEach(func(item interface{}) {
+		chunk := item.([]interface{})
+		chunks = append(chunks, chunk)
+	})
+	assert.EqualValues(t, [][]interface{}{
+		{1, 2, 3, 4},
+		{5, 6, 7, 8},
+		{9, 10},
+	}, chunks)
+}
+
 func TestTail(t *testing.T) {
 	var result int
 	Just(1, 2, 3, 4).Tail(2).Reduce(func(pipe <-chan interface{}) (interface{}, error) {
@@ -256,6 +310,14 @@ func TestTail(t *testing.T) {
 	assert.Equal(t, 7, result)
 }
 
+func TestTailZero(t *testing.T) {
+	assert.Panics(t, func() {
+		Just(1, 2, 3, 4).Tail(0).Reduce(func(pipe <-chan interface{}) (interface{}, error) {
+			return nil, nil
+		})
+	})
+}
+
 func TestWalk(t *testing.T) {
 	var result int
 	Just(1, 2, 3, 4, 5).Walk(func(item interface{}, pipe chan<- interface{}) {

core/fx/timeout.go

@@ -6,13 +6,17 @@ import (
 )
 
 var (
+	// ErrCanceled is the error returned when the context is canceled.
 	ErrCanceled = context.Canceled
-	ErrTimeout  = context.DeadlineExceeded
+	// ErrTimeout is the error returned when the context's deadline passes.
+	ErrTimeout = context.DeadlineExceeded
 )
 
-type FxOption func() context.Context
+// DoOption defines the method to customize a DoWithTimeout call.
+type DoOption func() context.Context
 
-func DoWithTimeout(fn func() error, timeout time.Duration, opts ...FxOption) error {
+// DoWithTimeout runs fn with timeout control.
+func DoWithTimeout(fn func() error, timeout time.Duration, opts ...DoOption) error {
 	parentCtx := context.Background()
 	for _, opt := range opts {
 		parentCtx = opt()
@@ -20,7 +24,8 @@ func DoWithTimeout(fn func() error, timeout time.Duration, opts ...FxOption) err
 	ctx, cancel := context.WithTimeout(parentCtx, timeout)
 	defer cancel()
 
-	done := make(chan error)
+	// create channel with buffer size 1 to avoid goroutine leak
+	done := make(chan error, 1)
 	panicChan := make(chan interface{}, 1)
 	go func() {
 		defer func() {
@@ -29,7 +34,6 @@ func DoWithTimeout(fn func() error, timeout time.Duration, opts ...FxOption) err
 			}
 		}()
 		done <- fn()
-		close(done)
 	}()
 
 	select {
@@ -42,7 +46,8 @@ func DoWithTimeout(fn func() error, timeout time.Duration, opts ...FxOption) err
 	}
 }
 
-func WithContext(ctx context.Context) FxOption {
+// WithContext customizes a DoWithTimeout call with given ctx.
+func WithContext(ctx context.Context) DoOption {
 	return func() context.Context {
 		return ctx
 	}

core/hash/consistenthash.go

@@ -11,6 +11,7 @@ import (
 )
 
 const (
+	// TopWeight is the top weight that one entry might set.
 	TopWeight = 100
 
 	minReplicas = 100
@@ -18,10 +19,12 @@ const (
 )
 
 type (
-	HashFunc func(data []byte) uint64
+	// Func defines the hash method.
+	Func func(data []byte) uint64
 
+	// A ConsistentHash is a ring hash implementation.
 	ConsistentHash struct {
-		hashFunc HashFunc
+		hashFunc Func
 		replicas int
 		keys     []uint64
 		ring     map[uint64][]interface{}
@@ -30,11 +33,13 @@ type (
 	}
 )
 
+// NewConsistentHash returns a ConsistentHash.
 func NewConsistentHash() *ConsistentHash {
 	return NewCustomConsistentHash(minReplicas, Hash)
 }
 
-func NewCustomConsistentHash(replicas int, fn HashFunc) *ConsistentHash {
+// NewCustomConsistentHash returns a ConsistentHash with given replicas and hash func.
+func NewCustomConsistentHash(replicas int, fn Func) *ConsistentHash {
 	if replicas < minReplicas {
 		replicas = minReplicas
 	}
@@ -92,6 +97,7 @@ func (h *ConsistentHash) AddWithWeight(node interface{}, weight int) {
 	h.AddWithReplicas(node, replicas)
 }
 
+// Get returns the corresponding node from h base on the given v.
 func (h *ConsistentHash) Get(v interface{}) (interface{}, bool) {
 	h.lock.RLock()
 	defer h.lock.RUnlock()
@@ -118,6 +124,7 @@ func (h *ConsistentHash) Get(v interface{}) (interface{}, bool) {
 	}
 }
 
+// Remove removes the given node from h.
 func (h *ConsistentHash) Remove(node interface{}) {
 	nodeRepr := repr(node)
 
@@ -133,7 +140,7 @@ func (h *ConsistentHash) Remove(node interface{}) {
 		index := sort.Search(len(h.keys), func(i int) bool {
 			return h.keys[i] >= hash
 		})
-		if index < len(h.keys) {
+		if index < len(h.keys) && h.keys[index] == hash {
 			h.keys = append(h.keys[:index], h.keys[index+1:]...)
 		}
 		h.removeRingNode(hash, nodeRepr)

core/hash/consistenthash_test.go

@@ -132,8 +132,8 @@ func TestConsistentHash_RemoveInterface(t *testing.T) {
 	assert.Equal(t, 1, len(ch.nodes))
 	node, ok := ch.Get(1)
 	assert.True(t, ok)
-	assert.Equal(t, key, node.(*MockNode).Addr)
+	assert.Equal(t, key, node.(*mockNode).addr)
-	assert.Equal(t, 2, node.(*MockNode).Id)
+	assert.Equal(t, 2, node.(*mockNode).id)
 }
 
 func getKeysBeforeAndAfterFailure(t *testing.T, prefix string, index int) (map[int]string, map[int]string) {
@@ -164,18 +164,18 @@ func getKeysBeforeAndAfterFailure(t *testing.T, prefix string, index int) (map[i
 	return keys, newKeys
 }
 
-type MockNode struct {
+type mockNode struct {
-	Addr string
+	addr string
-	Id   int
+	id   int
 }
 
-func newMockNode(addr string, id int) *MockNode {
+func newMockNode(addr string, id int) *mockNode {
-	return &MockNode{
+	return &mockNode{
-		Addr: addr,
+		addr: addr,
-		Id:   id,
+		id:   id,
 	}
 }
 
-func (n *MockNode) String() string {
+func (n *mockNode) String() string {
-	return n.Addr
+	return n.addr
 }

core/hash/hash.go

@@ -7,16 +7,19 @@ import (
 	"github.com/spaolacci/murmur3"
 )
 
+// Hash returns the hash value of data.
 func Hash(data []byte) uint64 {
 	return murmur3.Sum64(data)
 }
 
+// Md5 returns the md5 bytes of data.
 func Md5(data []byte) []byte {
 	digest := md5.New()
 	digest.Write(data)
 	return digest.Sum(nil)
 }
 
+// Md5Hex returns the md5 hex string of data.
 func Md5Hex(data []byte) string {
 	return fmt.Sprintf("%x", Md5(data))
 }

core/iox/bufferpool.go

@@ -5,11 +5,13 @@ import (
 	"sync"
 )
 
+// A BufferPool is a pool to buffer bytes.Buffer objects.
 type BufferPool struct {
 	capability int
 	pool       *sync.Pool
 }
 
+// NewBufferPool returns a BufferPool.
 func NewBufferPool(capability int) *BufferPool {
 	return &BufferPool{
 		capability: capability,
@@ -21,12 +23,14 @@ func NewBufferPool(capability int) *BufferPool {
 	}
 }
 
+// Get returns a bytes.Buffer object from bp.
 func (bp *BufferPool) Get() *bytes.Buffer {
 	buf := bp.pool.Get().(*bytes.Buffer)
 	buf.Reset()
 	return buf
 }
 
+// Put returns buf into bp.
 func (bp *BufferPool) Put(buf *bytes.Buffer) {
 	if buf.Cap() < bp.capability {
 		bp.pool.Put(buf)

core/iox/nopcloser.go

@@ -10,6 +10,7 @@ func (nopCloser) Close() error {
 	return nil
 }
 
+// NopCloser returns a io.WriteCloser that does nothing on calling Close.
 func NopCloser(w io.Writer) io.WriteCloser {
 	return nopCloser{w}
 }

core/iox/pipe.go

@@ -0,0 +1,23 @@
+package iox
+
+import "os"
+
+// RedirectInOut redirects stdin to r, stdout to w, and callers need to call restore afterwards.
+func RedirectInOut() (restore func(), err error) {
+	var r, w *os.File
+	r, w, err = os.Pipe()
+	if err != nil {
+		return
+	}
+
+	ow := os.Stdout
+	os.Stdout = w
+	or := os.Stdin
+	os.Stdin = r
+	restore = func() {
+		os.Stdin = or
+		os.Stdout = ow
+	}
+
+	return
+}

core/iox/pipe_test.go

@@ -0,0 +1,13 @@
+package iox
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRedirectInOut(t *testing.T) {
+	restore, err := RedirectInOut()
+	assert.Nil(t, err)
+	defer restore()
+}

core/iox/read.go

@@ -16,9 +16,11 @@ type (
 		omitPrefix    string
 	}
 
+	// TextReadOption defines the method to customize the text reading functions.
 	TextReadOption func(*textReadOptions)
 )
 
+// DupReadCloser returns two io.ReadCloser that read from the first will be written to the second.
 // The first returned reader needs to be read first, because the content
 // read from it will be written to the underlying buffer of the second reader.
 func DupReadCloser(reader io.ReadCloser) (io.ReadCloser, io.ReadCloser) {
@@ -27,6 +29,7 @@ func DupReadCloser(reader io.ReadCloser) (io.ReadCloser, io.ReadCloser) {
 	return ioutil.NopCloser(tee), ioutil.NopCloser(&buf)
 }
 
+// KeepSpace customizes the reading functions to keep leading and tailing spaces.
 func KeepSpace() TextReadOption {
 	return func(o *textReadOptions) {
 		o.keepSpace = true
@@ -49,6 +52,7 @@ func ReadBytes(reader io.Reader, buf []byte) error {
 	return nil
 }
 
+// ReadText reads content from the given file with leading and tailing spaces trimmed.
 func ReadText(filename string) (string, error) {
 	content, err := ioutil.ReadFile(filename)
 	if err != nil {
@@ -58,6 +62,7 @@ func ReadText(filename string) (string, error) {
 	return strings.TrimSpace(string(content)), nil
 }
 
+// ReadTextLines reads the text lines from given file.
 func ReadTextLines(filename string, opts ...TextReadOption) ([]string, error) {
 	var readOpts textReadOptions
 	for _, opt := range opts {
@@ -90,12 +95,14 @@ func ReadTextLines(filename string, opts ...TextReadOption) ([]string, error) {
 	return lines, scanner.Err()
 }
 
+// WithoutBlank customizes the reading functions to ignore blank lines.
 func WithoutBlank() TextReadOption {
 	return func(o *textReadOptions) {
 		o.withoutBlanks = true
 	}
 }
 
+// OmitWithPrefix customizes the reading functions to ignore the lines with given leading prefix.
 func OmitWithPrefix(prefix string) TextReadOption {
 	return func(o *textReadOptions) {
 		o.omitPrefix = prefix

core/iox/textfile.go

@@ -8,6 +8,7 @@ import (
 
 const bufSize = 32 * 1024
 
+// CountLines returns the number of lines in file.
 func CountLines(file string) (int, error) {
 	f, err := os.Open(file)
 	if err != nil {