preparing for v0.5

src/watcher/docker_watcher.go

@@ -0,0 +1,86 @@
+package watcher
+
+import (
+	"context"
+	"time"
+
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/filters"
+	D "github.com/yusing/go-proxy/docker"
+	E "github.com/yusing/go-proxy/error"
+)
+
+type DockerWatcher struct {
+	host string
+}
+
+func NewDockerWatcher(host string) *DockerWatcher {
+	return &DockerWatcher{host: host}
+}
+
+func (w *DockerWatcher) Events(ctx context.Context) (<-chan Event, <-chan E.NestedError) {
+	eventCh := make(chan Event)
+	errCh := make(chan E.NestedError)
+	started := make(chan struct{})
+
+	go func() {
+		defer close(errCh)
+
+		var cl D.Client
+		var err E.NestedError
+		for range 3 {
+			cl, err = D.ConnectClient(w.host)
+			if err.IsNotNil() {
+				break
+			}
+			errCh <- E.From(err)
+			time.Sleep(1 * time.Second)
+		}
+		if err.IsNotNil() {
+			errCh <- E.Failure("connect to docker")
+			return
+		}
+
+		cEventCh, cErrCh := cl.Events(ctx, dwOptions)
+		started <- struct{}{}
+
+		for {
+			select {
+			case <-ctx.Done():
+				errCh <- E.From(<-cErrCh)
+				return
+			case msg := <-cEventCh:
+				containerName, ok := msg.Actor.Attributes["name"]
+				if !ok {
+					// NOTE: should not happen
+					// but if it happens, just ignore it
+					continue
+				}
+				eventCh <- Event{
+					ActorName: containerName,
+					Action:    ActionModified,
+				}
+			case err := <-cErrCh:
+				errCh <- E.From(err)
+				select {
+				case <-ctx.Done():
+					return
+				default:
+					if D.IsErrConnectionFailed(err) {
+						time.Sleep(100 * time.Millisecond)
+						cEventCh, cErrCh = cl.Events(ctx, dwOptions)
+					}
+				}
+			}
+		}
+	}()
+	<-started
+
+	return eventCh, errCh
+}
+
+var dwOptions = types.EventsOptions{Filters: filters.NewArgs(
+	filters.Arg("type", "container"),
+	filters.Arg("event", "start"),
+	filters.Arg("event", "die"), // 'stop' already triggering 'die'
+)}