feat: added configuration center function (#3035)

Co-authored-by: aiden.ma <Aiden.ma@yijinin.com>

core/discov/internal/registry.go

@@ -10,13 +10,14 @@ import (
 	"sync"
 	"time"
 
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+	clientv3 "go.etcd.io/etcd/client/v3"
+
 	"github.com/zeromicro/go-zero/core/contextx"
 	"github.com/zeromicro/go-zero/core/lang"
 	"github.com/zeromicro/go-zero/core/logx"
 	"github.com/zeromicro/go-zero/core/syncx"
 	"github.com/zeromicro/go-zero/core/threading"
-	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
-	clientv3 "go.etcd.io/etcd/client/v3"
 )
 
 var (
@@ -45,7 +46,7 @@ func (r *Registry) GetConn(endpoints []string) (EtcdClient, error) {
 }
 
 // Monitor monitors the key on given etcd endpoints, notify with the given UpdateListener.
-func (r *Registry) Monitor(endpoints []string, key string, l UpdateListener) error {
+func (r *Registry) Monitor(endpoints []string, key string, l UpdateListener, disablePrefix bool) error {
 	c, exists := r.getCluster(endpoints)
 	// if exists, the existing values should be updated to the listener.
 	if exists {
@@ -55,7 +56,7 @@ func (r *Registry) Monitor(endpoints []string, key string, l UpdateListener) err
 		}
 	}
 
-	return c.monitor(key, l)
+	return c.monitor(key, l, disablePrefix)
 }
 
 func (r *Registry) getCluster(endpoints []string) (c *cluster, exists bool) {
@@ -79,13 +80,14 @@ func (r *Registry) getCluster(endpoints []string) (c *cluster, exists bool) {
 }
 
 type cluster struct {
-	endpoints  []string
-	key        string
-	values     map[string]map[string]string
-	listeners  map[string][]UpdateListener
-	watchGroup *threading.RoutineGroup
-	done       chan lang.PlaceholderType
-	lock       sync.RWMutex
+	endpoints     []string
+	key           string
+	values        map[string]map[string]string
+	listeners     map[string][]UpdateListener
+	watchGroup    *threading.RoutineGroup
+	done          chan lang.PlaceholderType
+	lock          sync.RWMutex
+	disablePrefix bool
 }
 
 func newCluster(endpoints []string) *cluster {
@@ -224,7 +226,12 @@ func (c *cluster) load(cli EtcdClient, key string) int64 {
 	for {
 		var err error
 		ctx, cancel := context.WithTimeout(c.context(cli), RequestTimeout)
-		resp, err = cli.Get(ctx, makeKeyPrefix(key), clientv3.WithPrefix())
+		if c.disablePrefix {
+			resp, err = cli.Get(ctx, key)
+		} else {
+			resp, err = cli.Get(ctx, makeKeyPrefix(key), clientv3.WithPrefix())
+		}
+
 		cancel()
 		if err == nil {
 			break
@@ -247,9 +254,10 @@ func (c *cluster) load(cli EtcdClient, key string) int64 {
 	return resp.Header.Revision
 }
 
-func (c *cluster) monitor(key string, l UpdateListener) error {
+func (c *cluster) monitor(key string, l UpdateListener, disablePrefix bool) error {
 	c.lock.Lock()
 	c.listeners[key] = append(c.listeners[key], l)
+	c.disablePrefix = disablePrefix
 	c.lock.Unlock()
 
 	cli, err := c.getClient()
@@ -315,14 +323,20 @@ func (c *cluster) watch(cli EtcdClient, key string, rev int64) {
 }
 
 func (c *cluster) watchStream(cli EtcdClient, key string, rev int64) error {
-	var rch clientv3.WatchChan
-	if rev != 0 {
-		rch = cli.Watch(clientv3.WithRequireLeader(c.context(cli)), makeKeyPrefix(key),
-			clientv3.WithPrefix(), clientv3.WithRev(rev+1))
-	} else {
-		rch = cli.Watch(clientv3.WithRequireLeader(c.context(cli)), makeKeyPrefix(key),
-			clientv3.WithPrefix())
+	var (
+		rch      clientv3.WatchChan
+		ops      []clientv3.OpOption
+		watchKey = key
+	)
+	if !c.disablePrefix {
+		watchKey = makeKeyPrefix(key)
+		ops = append(ops, clientv3.WithPrefix())
 	}
+	if rev != 0 {
+		ops = append(ops, clientv3.WithRev(rev+1))
+	}
+
+	rch = cli.Watch(clientv3.WithRequireLeader(c.context(cli)), watchKey, ops...)
 
 	for {
 		select {

core/discov/internal/registry_test.go

@@ -289,7 +289,7 @@ func TestRegistry_Monitor(t *testing.T) {
 		},
 	}
 	GetRegistry().lock.Unlock()
-	assert.Error(t, GetRegistry().Monitor(endpoints, "foo", new(mockListener)))
+	assert.Error(t, GetRegistry().Monitor(endpoints, "foo", new(mockListener), false))
 }
 
 type mockListener struct {

core/discov/subscriber.go

@@ -15,9 +15,10 @@ type (
 
 	// A Subscriber is used to subscribe the given key on an etcd cluster.
 	Subscriber struct {
-		endpoints []string
-		exclusive bool
-		items     *container
+		endpoints     []string
+		exclusive     bool
+		disablePrefix bool
+		items         *container
 	}
 )
 
@@ -34,7 +35,7 @@ func NewSubscriber(endpoints []string, key string, opts ...SubOption) (*Subscrib
 	}
 	sub.items = newContainer(sub.exclusive)
 
-	if err := internal.GetRegistry().Monitor(endpoints, key, sub.items); err != nil {
+	if err := internal.GetRegistry().Monitor(endpoints, key, sub.items, sub.disablePrefix); err != nil {
 		return nil, err
 	}
 
@@ -59,6 +60,13 @@ func Exclusive() SubOption {
 	}
 }
 
+// WithDisablePrefix turn off querying using key prefixes.
+func WithDisablePrefix() SubOption {
+	return func(sub *Subscriber) {
+		sub.disablePrefix = true
+	}
+}
+
 // WithSubEtcdAccount provides the etcd username/password.
 func WithSubEtcdAccount(user, pass string) SubOption {
 	return func(sub *Subscriber) {