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"
@@ -61,9 +62,7 @@ func init() {
 
 		for _, c := range clientMap {
 			delete(clientMap, c.key)
-			if c.Connected() {
-				c.Client.Close()
-			}
+			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 {