fix: routinegroup & etcd watch goroutine leak (#4514)

Co-authored-by: Kevin Wan <wanjunfeng@gmail.com>

core/discov/internal/registry.go

@@ -100,6 +100,8 @@ type cluster struct {
 	done       chan lang.PlaceholderType
 	lock       sync.RWMutex
 	exactMatch bool
+	watchCtx   map[string]context.CancelFunc
+	watchFlag  map[string]bool
 }
 
 func newCluster(endpoints []string) *cluster {
@@ -110,6 +112,8 @@ func newCluster(endpoints []string) *cluster {
 		listeners:  make(map[string][]UpdateListener),
 		watchGroup: threading.NewRoutineGroup(),
 		done:       make(chan lang.PlaceholderType),
+		watchCtx:   make(map[string]context.CancelFunc),
+		watchFlag:  make(map[string]bool),
 	}
 }
 
@@ -272,15 +276,17 @@ func (c *cluster) monitor(key string, l UpdateListener, exactMatch bool) error {
 	c.exactMatch = exactMatch
 	c.lock.Unlock()
 
-	cli, err := c.getClient()
-	if err != nil {
-		return err
-	}
+	if !c.watchFlag[key] {
+		cli, err := c.getClient()
+		if err != nil {
+			return err
+		}
 
-	rev := c.load(cli, key)
-	c.watchGroup.Run(func() {
-		c.watch(cli, key, rev)
-	})
+		rev := c.load(cli, key)
+		c.watchGroup.Run(func() {
+			c.watch(cli, key, rev)
+		})
+	}
 
 	return nil
 }
@@ -314,6 +320,7 @@ func (c *cluster) reload(cli EtcdClient) {
 	for k := range c.listeners {
 		keys = append(keys, k)
 	}
+	c.clearWatch()
 	c.lock.Unlock()
 
 	for _, key := range keys {
@@ -326,8 +333,9 @@ func (c *cluster) reload(cli EtcdClient) {
 }
 
 func (c *cluster) watch(cli EtcdClient, key string, rev int64) {
+	ctx := c.addWatch(key, cli)
 	for {
-		err := c.watchStream(cli, key, rev)
+		err := c.watchStream(cli, key, rev, ctx)
 		if err == nil {
 			return
 		}
@@ -342,7 +350,7 @@ func (c *cluster) watch(cli EtcdClient, key string, rev int64) {
 	}
 }
 
-func (c *cluster) watchStream(cli EtcdClient, key string, rev int64) error {
+func (c *cluster) watchStream(cli EtcdClient, key string, rev int64, ctx context.Context) error {
 	var (
 		rch      clientv3.WatchChan
 		ops      []clientv3.OpOption
@@ -356,7 +364,7 @@ func (c *cluster) watchStream(cli EtcdClient, key string, rev int64) error {
 		ops = append(ops, clientv3.WithRev(rev+1))
 	}
 
-	rch = cli.Watch(clientv3.WithRequireLeader(c.context(cli)), watchKey, ops...)
+	rch = cli.Watch(clientv3.WithRequireLeader(ctx), watchKey, ops...)
 
 	for {
 		select {
@@ -374,6 +382,8 @@ func (c *cluster) watchStream(cli EtcdClient, key string, rev int64) error {
 			c.handleWatchEvents(key, wresp.Events)
 		case <-c.done:
 			return nil
+		case <-ctx.Done():
+			return nil
 		}
 	}
 }
@@ -386,6 +396,23 @@ func (c *cluster) watchConnState(cli EtcdClient) {
 	watcher.watch(cli.ActiveConnection())
 }
 
+func (c *cluster) addWatch(key string, cli EtcdClient) context.Context {
+	ctx, cancel := context.WithCancel(cli.Ctx())
+	c.lock.Lock()
+	c.watchCtx[key] = cancel
+	c.watchFlag[key] = true
+	c.lock.Unlock()
+	return ctx
+}
+
+func (c *cluster) clearWatch() {
+	for _, cancel := range c.watchCtx {
+		cancel()
+	}
+	c.watchCtx = make(map[string]context.CancelFunc)
+	c.watchFlag = make(map[string]bool)
+}
+
 // DialClient dials an etcd cluster with given endpoints.
 func DialClient(endpoints []string) (EtcdClient, error) {
 	cfg := clientv3.Config{

core/discov/internal/registry_test.go

@@ -160,8 +160,10 @@ func TestCluster_Watch(t *testing.T) {
 			var wg sync.WaitGroup
 			wg.Add(1)
 			c := &cluster{
-				listeners: make(map[string][]UpdateListener),
 				values:    make(map[string]map[string]string),
+				listeners: make(map[string][]UpdateListener),
+				watchCtx:  make(map[string]context.CancelFunc),
+				watchFlag: make(map[string]bool),
 			}
 			listener := NewMockUpdateListener(ctrl)
 			c.listeners["any"] = []UpdateListener{listener}
@@ -211,7 +213,7 @@ func TestClusterWatch_RespFailures(t *testing.T) {
 			ch := make(chan clientv3.WatchResponse)
 			cli.EXPECT().Watch(gomock.Any(), "any/", gomock.Any()).Return(ch).AnyTimes()
 			cli.EXPECT().Ctx().Return(context.Background()).AnyTimes()
-			c := new(cluster)
+			c := newCluster([]string{})
 			c.done = make(chan lang.PlaceholderType)
 			go func() {
 				ch <- resp
@@ -231,7 +233,7 @@ func TestClusterWatch_CloseChan(t *testing.T) {
 	ch := make(chan clientv3.WatchResponse)
 	cli.EXPECT().Watch(gomock.Any(), "any/", gomock.Any()).Return(ch).AnyTimes()
 	cli.EXPECT().Ctx().Return(context.Background()).AnyTimes()
-	c := new(cluster)
+	c := newCluster([]string{})
 	c.done = make(chan lang.PlaceholderType)
 	go func() {
 		close(ch)
@@ -240,6 +242,37 @@ func TestClusterWatch_CloseChan(t *testing.T) {
 	c.watch(cli, "any", 0)
 }
 
+func TestClusterWatch_CtxCancel(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+	cli := NewMockEtcdClient(ctrl)
+	restore := setMockClient(cli)
+	defer restore()
+	ch := make(chan clientv3.WatchResponse)
+	cli.EXPECT().Watch(gomock.Any(), "any/", gomock.Any()).Return(ch).AnyTimes()
+	ctx, cancelFunc := context.WithCancel(context.Background())
+	cli.EXPECT().Ctx().Return(ctx).AnyTimes()
+	c := newCluster([]string{})
+	c.done = make(chan lang.PlaceholderType)
+	go func() {
+		cancelFunc()
+		close(ch)
+	}()
+	c.watch(cli, "any", 0)
+}
+
+func TestCluster_ClearWatch(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	c := &cluster{
+		watchCtx:  map[string]context.CancelFunc{"foo": cancel},
+		watchFlag: map[string]bool{"foo": true},
+	}
+	c.clearWatch()
+	assert.Equal(t, ctx.Err(), context.Canceled)
+	assert.Equal(t, 0, len(c.watchCtx))
+	assert.Equal(t, 0, len(c.watchFlag))
+}
+
 func TestValueOnlyContext(t *testing.T) {
 	ctx := contextx.ValueOnlyFrom(context.Background())
 	ctx.Done()
@@ -286,6 +319,8 @@ func TestRegistry_Monitor(t *testing.T) {
 					"bar": "baz",
 				},
 			},
+			watchCtx:  map[string]context.CancelFunc{},
+			watchFlag: map[string]bool{},
 		},
 	}
 	GetRegistry().lock.Unlock()
@@ -293,15 +328,11 @@ func TestRegistry_Monitor(t *testing.T) {
 }
 
 func TestRegistry_Unmonitor(t *testing.T) {
-	svr, err := mockserver.StartMockServers(1)
-	assert.NoError(t, err)
-	svr.StartAt(0)
-
-	endpoints := []string{svr.Servers[0].Address}
+	l := new(mockListener)
 	GetRegistry().lock.Lock()
 	GetRegistry().clusters = map[string]*cluster{
 		getClusterKey(endpoints): {
-			listeners: map[string][]UpdateListener{},
+			listeners: map[string][]UpdateListener{"foo": {l}},
 			values: map[string]map[string]string{
 				"foo": {
 					"bar": "baz",

core/discov/subscriber.go

@@ -20,6 +20,7 @@ type (
 		key        string
 		exclusive  bool
 		exactMatch bool
+		key        string
 		items      *container
 	}
 )
@@ -31,6 +32,7 @@ type (
 func NewSubscriber(endpoints []string, key string, opts ...SubOption) (*Subscriber, error) {
 	sub := &Subscriber{
 		endpoints: endpoints,
+		key:       key,
 	}
 	for _, opt := range opts {
 		opt(sub)

core/discov/subscriber_test.go

@@ -214,6 +214,18 @@ func TestSubscriber(t *testing.T) {
 	assert.Equal(t, int32(1), atomic.LoadInt32(&count))
 }
 
+func TestSubscriberClos(t *testing.T) {
+	l := newContainer(false)
+	sub := &Subscriber{
+		endpoints: []string{"localhost:2379"},
+		key:       "foo",
+		items:     l,
+	}
+	_ = internal.GetRegistry().Monitor(sub.endpoints, sub.key, l, false)
+	sub.Close()
+	assert.Empty(t, sub.items.listeners)
+}
+
 func TestWithSubEtcdAccount(t *testing.T) {
 	endpoints := []string{"localhost:2379"}
 	user := stringx.Rand()

zrpc/resolver/internal/resolver_test.go

@@ -1,6 +1,7 @@
 package internal
 
 import (
+	"github.com/zeromicro/go-zero/core/discov"
 	"testing"
 
 	"github.com/stretchr/testify/assert"