X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/dd2320c6877939365caf79767b5244d86a288437..b3b8d695afb1a7624ece94f4c5dcdd671030374e:/services/ws/handler.go

diff --git a/services/ws/handler.go b/services/ws/handler.go
index ca9231c986..d527c39ba1 100644
--- a/services/ws/handler.go
+++ b/services/ws/handler.go
@@ -1,3 +1,7 @@
+// Copyright (C) The Arvados Authors. All rights reserved.
+//
+// SPDX-License-Identifier: AGPL-3.0
+
 package main
 
 import (
@@ -31,6 +35,7 @@ func (h *handler) Handle(ws wsConn, eventSource eventSource, newSession func(wsC
 	h.setupOnce.Do(h.setup)
 
 	ctx, cancel := context.WithCancel(ws.Request().Context())
+	defer cancel()
 	log := logger(ctx)
 
 	incoming := eventSource.NewSink()
@@ -52,7 +57,10 @@ func (h *handler) Handle(ws wsConn, eventSource eventSource, newSession func(wsC
 		return
 	}
 
+	// Receive websocket frames from the client and pass them to
+	// sess.Receive().
 	go func() {
+		defer cancel()
 		buf := make([]byte, 2<<20)
 		for {
 			select {
@@ -68,22 +76,24 @@ func (h *handler) Handle(ws wsConn, eventSource eventSource, newSession func(wsC
 				err = errFrameTooBig
 			}
 			if err != nil {
-				if err != io.EOF {
+				if err != io.EOF && ctx.Err() == nil {
 					log.WithError(err).Info("read error")
 				}
-				cancel()
 				return
 			}
 			err = sess.Receive(buf)
 			if err != nil {
 				log.WithError(err).Error("sess.Receive() failed")
-				cancel()
 				return
 			}
 		}
 	}()
 
+	// Take items from the outgoing queue, serialize them using
+	// sess.EventMessage() as needed, and send them to the client
+	// as websocket frames.
 	go func() {
+		defer cancel()
 		for {
 			var ok bool
 			var data interface{}
@@ -109,8 +119,7 @@ func (h *handler) Handle(ws wsConn, eventSource eventSource, newSession func(wsC
 				buf, err = sess.EventMessage(e)
 				if err != nil {
 					log.WithError(err).Error("EventMessage failed")
-					cancel()
-					break
+					return
 				} else if len(buf) == 0 {
 					log.Debug("skip")
 					continue
@@ -125,9 +134,10 @@ func (h *handler) Handle(ws wsConn, eventSource eventSource, newSession func(wsC
 			t0 := time.Now()
 			_, err = ws.Write(buf)
 			if err != nil {
-				log.WithError(err).Error("write failed")
-				cancel()
-				break
+				if ctx.Err() == nil {
+					log.WithError(err).Error("write failed")
+				}
+				return
 			}
 			log.Debug("sent")
 
@@ -149,6 +159,7 @@ func (h *handler) Handle(ws wsConn, eventSource eventSource, newSession func(wsC
 	// is done/cancelled or the incoming event stream ends. Shut
 	// down the handler if the outgoing queue fills up.
 	go func() {
+		defer cancel()
 		ticker := time.NewTicker(h.PingTimeout)
 		defer ticker.Stop()
 
@@ -168,10 +179,8 @@ func (h *handler) Handle(ws wsConn, eventSource eventSource, newSession func(wsC
 					default:
 					}
 				}
-				continue
 			case e, ok := <-incoming.Channel():
 				if !ok {
-					cancel()
 					return
 				}
 				if !sess.Filter(e) {
@@ -181,7 +190,6 @@ func (h *handler) Handle(ws wsConn, eventSource eventSource, newSession func(wsC
 				case queue <- e:
 				default:
 					log.WithError(errQueueFull).Error("terminate")
-					cancel()
 					return
 				}
 			}