docker: clear routes on docker disconnect, reload routes on connection restore

internal/watcher/docker_watcher.go

@@ -2,19 +2,22 @@ package watcher
 
 import (
 	"context"
+	"errors"
 	"time"
 
 	docker_events "github.com/docker/docker/api/types/events"
 	"github.com/docker/docker/api/types/filters"
-	D "github.com/yusing/go-proxy/internal/docker"
+	"github.com/docker/docker/client"
+	"github.com/yusing/go-proxy/internal/docker"
 	"github.com/yusing/go-proxy/internal/gperr"
+	"github.com/yusing/go-proxy/internal/logging"
 	"github.com/yusing/go-proxy/internal/watcher/events"
 )
 
 type (
 	DockerWatcher struct {
 		host        string
-		client      *D.SharedClient
+		client      *docker.SharedClient
 		clientOwned bool
 	}
 	DockerListOptions = docker_events.ListOptions
@@ -42,38 +45,66 @@ var (
 	)}
 
 	dockerWatcherRetryInterval = 3 * time.Second
+
+	reloadTrigger = Event{
+		Type:            events.EventTypeDocker,
+		Action:          events.ActionForceReload,
+		ActorAttributes: map[string]string{},
+		ActorName:       "",
+		ActorID:         "",
+	}
 )
 
 func DockerFilterContainerNameID(nameOrID string) filters.KeyValuePair {
 	return filters.Arg("container", nameOrID)
 }
 
-func NewDockerWatcher(host string) DockerWatcher {
-	return DockerWatcher{
+func NewDockerWatcher(host string) *DockerWatcher {
+	return &DockerWatcher{
 		host:        host,
 		clientOwned: true,
 	}
 }
 
-func NewDockerWatcherWithClient(client *D.SharedClient) DockerWatcher {
-	return DockerWatcher{
+func NewDockerWatcherWithClient(client *docker.SharedClient) *DockerWatcher {
+	return &DockerWatcher{
 		client: client,
 	}
 }
 
-func (w DockerWatcher) Events(ctx context.Context) (<-chan Event, <-chan gperr.Error) {
+func (w *DockerWatcher) Events(ctx context.Context) (<-chan Event, <-chan gperr.Error) {
 	return w.EventsWithOptions(ctx, optionsDefault)
 }
 
-func (w DockerWatcher) Close() {
+func (w *DockerWatcher) Close() {
 	if w.clientOwned && w.client.Connected() {
 		w.client.Close()
 	}
 }
 
-func (w DockerWatcher) EventsWithOptions(ctx context.Context, options DockerListOptions) (<-chan Event, <-chan gperr.Error) {
-	eventCh := make(chan Event, 100)
-	errCh := make(chan gperr.Error, 10)
+func (w *DockerWatcher) parseError(err error) gperr.Error {
+	if errors.Is(err, context.DeadlineExceeded) {
+		return gperr.New("docker client connection timeout")
+	}
+	if client.IsErrConnectionFailed(err) {
+		return gperr.New("docker client connection failure")
+	}
+	return gperr.Wrap(err)
+}
+
+func (w *DockerWatcher) checkConnection(ctx context.Context) bool {
+	ctx, cancel := context.WithTimeout(ctx, dockerWatcherRetryInterval)
+	defer cancel()
+	_, err := w.client.Ping(ctx)
+	if err != nil {
+		return false
+	}
+	return true
+}
+
+func (w *DockerWatcher) EventsWithOptions(ctx context.Context, options DockerListOptions) (<-chan Event, <-chan gperr.Error) {
+	eventCh := make(chan Event)
+	errCh := make(chan gperr.Error)
 
 	go func() {
 		defer func() {
@@ -84,7 +115,7 @@ func (w DockerWatcher) EventsWithOptions(ctx context.Context, options DockerList
 
 		if !w.client.Connected() {
 			var err error
-			w.client, err = D.ConnectClient(w.host)
+			w.client, err = docker.ConnectClient(w.host)
 			attempts := 0
 			retryTicker := time.NewTicker(dockerWatcherRetryInterval)
 			for err != nil {
@@ -95,7 +126,7 @@ func (w DockerWatcher) EventsWithOptions(ctx context.Context, options DockerList
 					retryTicker.Stop()
 					return
 				case <-retryTicker.C:
-					w.client, err = D.ConnectClient(w.host)
+					w.client, err = docker.ConnectClient(w.host)
 				}
 			}
 			retryTicker.Stop()
@@ -104,7 +135,7 @@ func (w DockerWatcher) EventsWithOptions(ctx context.Context, options DockerList
 		defer w.Close()
 
 		cEventCh, cErrCh := w.client.Events(ctx, options)
-
+		defer logging.Debug().Str("host", w.host).Msg("docker watcher closed")
 		for {
 			select {
 			case <-ctx.Done():
@@ -126,14 +157,21 @@ func (w DockerWatcher) EventsWithOptions(ctx context.Context, options DockerList
 				if err == nil {
 					continue
 				}
-				errCh <- gperr.Wrap(err)
-				select {
-				case <-ctx.Done():
-					return
-				default:
-					time.Sleep(dockerWatcherRetryInterval)
-					cEventCh, cErrCh = w.client.Events(ctx, options)
+				errCh <- w.parseError(err)
+				// trigger reload (clear routes)
+				eventCh <- reloadTrigger
+				for !w.checkConnection(ctx) {
+					select {
+					case <-ctx.Done():
+						return
+					case <-time.After(dockerWatcherRetryInterval):
+						continue
+					}
 				}
+				// connection successful, trigger reload (reload routes)
+				eventCh <- reloadTrigger
+				// reopen event channel
+				cEventCh, cErrCh = w.client.Events(ctx, options)
 			}
 		}
 	}()

internal/watcher/events/events.go

@@ -34,6 +34,8 @@ const (
 	ActionContainerDie
 	ActionContainerDestroy
 
+	ActionForceReload
+
 	actionContainerWakeMask  = ActionContainerCreate | ActionContainerStart | ActionContainerUnpause
 	actionContainerSleepMask = ActionContainerKill | ActionContainerStop | ActionContainerPause | ActionContainerDie
 )