Merge pull request #20792 from cpuguy83/more_stats_client_cleanup

Fixes issue with stats on start event

api/client/events.go

@@ -6,10 +6,12 @@ import (
 	"io"
 	"sort"
 	"strings"
+	"sync"
 	"time"
 
 	"golang.org/x/net/context"
 
+	"github.com/Sirupsen/logrus"
 	Cli "github.com/docker/docker/cli"
 	"github.com/docker/docker/opts"
 	"github.com/docker/docker/pkg/jsonlog"
@@ -115,3 +117,31 @@ func printOutput(event eventtypes.Message, output io.Writer) {
 	}
 	fmt.Fprint(output, "\n")
 }
+
+type eventHandler struct {
+	handlers map[string]func(eventtypes.Message)
+	mu       sync.Mutex
+	closed   bool
+}
+
+func (w *eventHandler) Handle(action string, h func(eventtypes.Message)) {
+	w.mu.Lock()
+	w.handlers[action] = h
+	w.mu.Unlock()
+}
+
+// Watch ranges over the passed in event chan and processes the events based on the
+// handlers created for a given action.
+// To stop watching, close the event chan.
+func (w *eventHandler) Watch(c <-chan eventtypes.Message) {
+	for e := range c {
+		w.mu.Lock()
+		h, exists := w.handlers[e.Action]
+		w.mu.Unlock()
+		if !exists {
+			continue
+		}
+		logrus.Debugf("event handler: received event: %v", e)
+		go h(e)
+	}
+}