fix docker client data race on Close(), remove SharedClient.IsConnected

internal/docker/client.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"net/http"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/docker/cli/cli/connhelper"
@@ -61,10 +62,8 @@ func init() {
 
 		for _, c := range clientMap {
 			delete(clientMap, c.key)
-			if c.Connected() {
 			c.Client.Close()
 		}
-		}
 	})
 }
 
@@ -75,10 +74,6 @@ func closeTimedOutClients() {
 	now := time.Now().Unix()
 
 	for _, c := range clientMap {
-		if !c.Connected() {
-			delete(clientMap, c.key)
-			continue
-		}
 		if c.closedOn == 0 {
 			continue
 		}
@@ -90,14 +85,10 @@ func closeTimedOutClients() {
 	}
 }
 
-func (c *SharedClient) Connected() bool {
-	return c != nil && c.Client != nil
-}
-
 // if the client is still referenced, this is no-op.
 func (c *SharedClient) Close() {
-	c.closedOn = time.Now().Unix()
-	c.refCount--
+	atomic.StoreInt64(&c.closedOn, time.Now().Unix())
+	atomic.AddUint32(&c.refCount, ^uint32(0))
 }
 
 // ConnectClient creates a new Docker client connection to the specified host.
@@ -115,8 +106,8 @@ func ConnectClient(host string) (*SharedClient, error) {
 	defer clientMapMu.Unlock()
 
 	if client, ok := clientMap[host]; ok {
-		client.closedOn = 0
-		client.refCount++
+		atomic.StoreInt64(&client.closedOn, 0)
+		atomic.AddUint32(&client.refCount, 1)
 		return client, nil
 	}
 

internal/docker/idlewatcher/watcher.go

@@ -146,9 +146,6 @@ func (w *Watcher) containerStart(ctx context.Context) error {
 }
 
 func (w *Watcher) containerStatus() (string, error) {
-	if !w.client.Connected() {
-		return "", errors.New("docker client not connected")
-	}
 	ctx, cancel := context.WithTimeoutCause(w.task.Context(), dockerReqTimeout, errors.New("docker request timeout"))
 	defer cancel()
 	json, err := w.client.ContainerInspect(ctx, w.ContainerID)
@@ -242,7 +239,7 @@ func (w *Watcher) getEventCh(dockerWatcher watcher.DockerWatcher) (eventCh <-cha
 // it exits only if the context is canceled, the container is destroyed,
 // errors occurred on docker client, or route provider died (mainly caused by config reload).
 func (w *Watcher) watchUntilDestroy() (returnCause error) {
-	dockerWatcher := watcher.NewDockerWatcherWithClient(w.client)
+	dockerWatcher := watcher.NewDockerWatcher(w.client.DaemonHost())
 	dockerEventCh, dockerEventErrCh := w.getEventCh(dockerWatcher)
 
 	for {

internal/watcher/docker_watcher.go

@@ -6,20 +6,15 @@ import (
 
 	docker_events "github.com/docker/docker/api/types/events"
 	"github.com/docker/docker/api/types/filters"
-	"github.com/rs/zerolog"
 	D "github.com/yusing/go-proxy/internal/docker"
 	E "github.com/yusing/go-proxy/internal/error"
-	"github.com/yusing/go-proxy/internal/logging"
 	"github.com/yusing/go-proxy/internal/watcher/events"
 )
 
 type (
 	DockerWatcher struct {
-		zerolog.Logger
-
 		host   string
 		client *D.SharedClient
-		clientOwned bool
 	}
 	DockerListOptions = docker_events.ListOptions
 )
@@ -53,24 +48,7 @@ func DockerFilterContainerNameID(nameOrID string) filters.KeyValuePair {
 }
 
 func NewDockerWatcher(host string) DockerWatcher {
-	return DockerWatcher{
-		host:        host,
-		clientOwned: true,
-		Logger: logging.With().
-			Str("type", "docker").
-			Str("host", host).
-			Logger(),
-	}
-}
-
-func NewDockerWatcherWithClient(client *D.SharedClient) DockerWatcher {
-	return DockerWatcher{
-		client: client,
-		Logger: logging.With().
-			Str("type", "docker").
-			Str("host", client.DaemonHost()).
-			Logger(),
-	}
+	return DockerWatcher{host: host}
 }
 
 func (w DockerWatcher) Events(ctx context.Context) (<-chan Event, <-chan E.Error) {
@@ -82,36 +60,12 @@ func (w DockerWatcher) EventsWithOptions(ctx context.Context, options DockerList
 	errCh := make(chan E.Error)
 
 	go func() {
+		defer func() {
 			defer close(eventCh)
 			defer close(errCh)
-
-		defer func() {
-			if w.clientOwned && w.client.Connected() {
 			w.client.Close()
-			}
 		}()
 
-		if !w.client.Connected() {
-			var err error
-			attempts := 0
-			for {
-				w.client, err = D.ConnectClient(w.host)
-				if err == nil {
-					break
-				}
-				attempts++
-				errCh <- E.Errorf("docker connection attempt #%d: %w", attempts, err)
-				select {
-				case <-ctx.Done():
-					return
-				default:
-					time.Sleep(dockerWatcherRetryInterval)
-				}
-			}
-		}
-
-		defer w.client.Close()
-
 		cEventCh, cErrCh := w.client.Events(ctx, options)
 
 		for {
@@ -124,7 +78,6 @@ func (w DockerWatcher) EventsWithOptions(ctx context.Context, options DockerList
 			case msg := <-cEventCh:
 				action, ok := events.DockerEventMap[msg.Action]
 				if !ok {
-					w.Debug().Msgf("ignored unknown docker event: %s for container %s", msg.Action, msg.Actor.Attributes["name"])
 					continue
 				}
 				event := Event{