implement `--until` flag for swarm api

- mostly copied the idea from base docker
 - refactored the locking in event handling
 - integration test for until flag

Signed-off-by: Morgan Bauer <mbauer@us.ibm.com>

api/events.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"net/http"
 	"sync"
+	"time"
 
 	"github.com/docker/swarm/cluster"
 )
@@ -34,12 +35,34 @@ func (eh *eventsHandler) Add(remoteAddr string, w io.Writer) {
 }
 
 // Wait waits on a signal from the remote address.
-func (eh *eventsHandler) Wait(remoteAddr string) {
-	<-eh.cs[remoteAddr]
+func (eh *eventsHandler) Wait(remoteAddr string, until int64) {
+
+	timer := time.NewTimer(0)
+	timer.Stop()
+	if until > 0 {
+		dur := time.Unix(until, 0).Sub(time.Now())
+		timer = time.NewTimer(dur)
+	}
+
+	select {
+	case <-eh.cs[remoteAddr]:
+	case <-timer.C: // `--until` timeout
+		close(eh.cs[remoteAddr])
+	}
+	eh.cleanupHandler(remoteAddr)
+}
+
+func (eh *eventsHandler) cleanupHandler(remoteAddr string) {
+	eh.Lock()
+	// the maps are expected to have the same keys
+	delete(eh.cs, remoteAddr)
+	delete(eh.ws, remoteAddr)
+	eh.Unlock()
+
 }
 
 // Handle writes information about a cluster event to each remote address in the cluster that has been added to the events handler.
-// After a successful write to a remote address, the associated channel is closed and the address is removed from the events handler.
+// After an unsuccessful write to a remote address, the associated channel is closed and the address is removed from the events handler.
 func (eh *eventsHandler) Handle(e *cluster.Event) error {
 	eh.RLock()
 
@@ -66,24 +89,16 @@ func (eh *eventsHandler) Handle(e *cluster.Event) error {
 		if f, ok := w.(http.Flusher); ok {
 			f.Flush()
 		}
-
 	}
 
 	eh.RUnlock()
 
 	if len(failed) > 0 {
-		eh.Lock()
-
 		for _, key := range failed {
 			if ch, ok := eh.cs[key]; ok {
 				close(ch)
-				// the maps are expected to have the same keys
-				delete(eh.cs, key)
-				delete(eh.ws, key)
 			}
 		}
-
-		eh.Unlock()
 	}
 
 	return nil

api/handlers.go

@@ -485,6 +485,21 @@ func postImagesLoad(c *context, w http.ResponseWriter, r *http.Request) {
 
 // GET /events
 func getEvents(c *context, w http.ResponseWriter, r *http.Request) {
+	if err := r.ParseForm(); err != nil {
+		httpError(w, err.Error(), 400)
+		return
+	}
+
+	var until int64 = -1
+	if r.Form.Get("until") != "" {
+		u, err := strconv.ParseInt(r.Form.Get("until"), 10, 64)
+		if err != nil {
+			httpError(w, err.Error(), 400)
+			return
+		}
+		until = u
+	}
+
 	c.eventsHandler.Add(r.RemoteAddr, w)
 
 	w.Header().Set("Content-Type", "application/json")
@@ -493,7 +508,7 @@ func getEvents(c *context, w http.ResponseWriter, r *http.Request) {
 		f.Flush()
 	}
 
-	c.eventsHandler.Wait(r.RemoteAddr)
+	c.eventsHandler.Wait(r.RemoteAddr, until)
 }
 
 // POST /containers/{name:.*}/exec

test/integration/api/events.bats

@@ -17,7 +17,7 @@ function teardown() {
 	local events_pid="$!"
 
 	# This should emit 3 events: create, start, die.
-	docker_swarm run --name test_container -e constraint:node==node-0 busybox true
+	docker_swarm run -d --name test_container -e constraint:node==node-0 busybox true
 
 	# events might take a little big to show up, wait until we get the last one.
 	retry 5 0.5 grep -q "die" "$log_file"
@@ -25,7 +25,10 @@ function teardown() {
 	# clean up `docker events`
 	kill "$events_pid"
 
-	# verify
+	# verify size
+	[[ $(wc -l < ${log_file}) == 3 ]]
+
+	# verify content
 	run cat "$log_file"
 	[ "$status" -eq 0 ]
 	[[ "${output}" == *"node:node-0"* ]]
@@ -36,3 +39,27 @@ function teardown() {
 	# after ok, remove the log file
 	rm -f "$log_file"
 }
+
+
+@test "docker events until" {
+	# produce less output because we timed out
+	start_docker_with_busybox 2
+	swarm_manage
+
+	# start events, report real time events to $log_file
+	local log_file=$(mktemp)
+	ONE_SECOND_IN_THE_PAST=$(($(date +%s) - 1))
+	docker_swarm events --until ${ONE_SECOND_IN_THE_PAST} > "$log_file"
+
+	# This should emit 3 events: create, start, die.
+	docker_swarm run --name test_container -e constraint:node==node-0 busybox true
+
+	# do not need to kill events, it's already dead
+
+	# verify size
+	[[ $(wc -l < ${log_file}) == 0 ]]
+	# no content, so nothing else to verify
+
+	# after ok, remove the log file
+	rm -f "$log_file"
+}