Rely on request.Context() cancellation

The cancellable handler is no longer needed as the context that is
passed with the http request will be cancelled just like the close
notifier was doing.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

api/server/router/build/build.go

@@ -31,8 +31,8 @@ func (r *buildRouter) Routes() []router.Route {
 
 func (r *buildRouter) initRoutes() {
 	r.routes = []router.Route{
-		router.NewPostRoute("/build", r.postBuild, router.WithCancel),
-		router.NewPostRoute("/build/prune", r.postPrune, router.WithCancel),
+		router.NewPostRoute("/build", r.postBuild),
+		router.NewPostRoute("/build/prune", r.postPrune),
 		router.NewPostRoute("/build/cancel", r.postCancel),
 	}
 }

api/server/router/container/container.go

@@ -38,8 +38,8 @@ func (r *containerRouter) initRoutes() {
 		router.NewGetRoute("/containers/{name:.*}/changes", r.getContainersChanges),
 		router.NewGetRoute("/containers/{name:.*}/json", r.getContainersByName),
 		router.NewGetRoute("/containers/{name:.*}/top", r.getContainersTop),
-		router.NewGetRoute("/containers/{name:.*}/logs", r.getContainersLogs, router.WithCancel),
-		router.NewGetRoute("/containers/{name:.*}/stats", r.getContainersStats, router.WithCancel),
+		router.NewGetRoute("/containers/{name:.*}/logs", r.getContainersLogs),
+		router.NewGetRoute("/containers/{name:.*}/stats", r.getContainersStats),
 		router.NewGetRoute("/containers/{name:.*}/attach/ws", r.wsContainersAttach),
 		router.NewGetRoute("/exec/{id:.*}/json", r.getExecByID),
 		router.NewGetRoute("/containers/{name:.*}/archive", r.getContainersArchive),
@@ -51,7 +51,7 @@ func (r *containerRouter) initRoutes() {
 		router.NewPostRoute("/containers/{name:.*}/restart", r.postContainersRestart),
 		router.NewPostRoute("/containers/{name:.*}/start", r.postContainersStart),
 		router.NewPostRoute("/containers/{name:.*}/stop", r.postContainersStop),
-		router.NewPostRoute("/containers/{name:.*}/wait", r.postContainersWait, router.WithCancel),
+		router.NewPostRoute("/containers/{name:.*}/wait", r.postContainersWait),
 		router.NewPostRoute("/containers/{name:.*}/resize", r.postContainersResize),
 		router.NewPostRoute("/containers/{name:.*}/attach", r.postContainersAttach),
 		router.NewPostRoute("/containers/{name:.*}/copy", r.postContainersCopy), // Deprecated since 1.8, Errors out since 1.12
@@ -60,7 +60,7 @@ func (r *containerRouter) initRoutes() {
 		router.NewPostRoute("/exec/{name:.*}/resize", r.postContainerExecResize),
 		router.NewPostRoute("/containers/{name:.*}/rename", r.postContainerRename),
 		router.NewPostRoute("/containers/{name:.*}/update", r.postContainerUpdate),
-		router.NewPostRoute("/containers/prune", r.postContainersPrune, router.WithCancel),
+		router.NewPostRoute("/containers/prune", r.postContainersPrune),
 		router.NewPostRoute("/commit", r.postCommit),
 		// PUT
 		router.NewPutRoute("/containers/{name:.*}/archive", r.putContainersArchive),

api/server/router/container/container_routes.go

@@ -338,9 +338,6 @@ func (s *containerRouter) postContainersWait(ctx context.Context, w http.Respons
 		}
 	}
 
-	// Note: the context should get canceled if the client closes the
-	// connection since this handler has been wrapped by the
-	// router.WithCancel() wrapper.
 	waitC, err := s.backend.ContainerWait(ctx, vars["name"], waitCondition)
 	if err != nil {
 		return err

api/server/router/image/image.go

@@ -34,10 +34,10 @@ func (r *imageRouter) initRoutes() {
 		router.NewGetRoute("/images/{name:.*}/json", r.getImagesByName),
 		// POST
 		router.NewPostRoute("/images/load", r.postImagesLoad),
-		router.NewPostRoute("/images/create", r.postImagesCreate, router.WithCancel),
-		router.NewPostRoute("/images/{name:.*}/push", r.postImagesPush, router.WithCancel),
+		router.NewPostRoute("/images/create", r.postImagesCreate),
+		router.NewPostRoute("/images/{name:.*}/push", r.postImagesPush),
 		router.NewPostRoute("/images/{name:.*}/tag", r.postImagesTag),
-		router.NewPostRoute("/images/prune", r.postImagesPrune, router.WithCancel),
+		router.NewPostRoute("/images/prune", r.postImagesPrune),
 		// DELETE
 		router.NewDeleteRoute("/images/{name:.*}", r.deleteImages),
 	}

api/server/router/local.go

@@ -1,9 +1,6 @@
 package router // import "github.com/docker/docker/api/server/router"
 
 import (
-	"context"
-	"net/http"
-
 	"github.com/docker/docker/api/server/httputils"
 )
 
@@ -72,33 +69,3 @@ func NewOptionsRoute(path string, handler httputils.APIFunc, opts ...RouteWrappe
 func NewHeadRoute(path string, handler httputils.APIFunc, opts ...RouteWrapper) Route {
 	return NewRoute("HEAD", path, handler, opts...)
 }
-
-func cancellableHandler(h httputils.APIFunc) httputils.APIFunc {
-	return func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
-		if notifier, ok := w.(http.CloseNotifier); ok {
-			notify := notifier.CloseNotify()
-			notifyCtx, cancel := context.WithCancel(ctx)
-			finished := make(chan struct{})
-			defer close(finished)
-			ctx = notifyCtx
-			go func() {
-				select {
-				case <-notify:
-					cancel()
-				case <-finished:
-				}
-			}()
-		}
-		return h(ctx, w, r, vars)
-	}
-}
-
-// WithCancel makes new route which embeds http.CloseNotifier feature to
-// context.Context of handler.
-func WithCancel(r Route) Route {
-	return localRoute{
-		method:  r.Method(),
-		path:    r.Path(),
-		handler: cancellableHandler(r.Handler()),
-	}
-}

api/server/router/network/network.go

@@ -36,7 +36,7 @@ func (r *networkRouter) initRoutes() {
 		router.NewPostRoute("/networks/create", r.postNetworkCreate),
 		router.NewPostRoute("/networks/{id:.*}/connect", r.postNetworkConnect),
 		router.NewPostRoute("/networks/{id:.*}/disconnect", r.postNetworkDisconnect),
-		router.NewPostRoute("/networks/prune", r.postNetworksPrune, router.WithCancel),
+		router.NewPostRoute("/networks/prune", r.postNetworksPrune),
 		// DELETE
 		router.NewDeleteRoute("/networks/{id:.*}", r.deleteNetwork),
 	}

api/server/router/plugin/plugin.go

@@ -28,11 +28,11 @@ func (r *pluginRouter) initRoutes() {
 		router.NewGetRoute("/plugins/{name:.*}/json", r.inspectPlugin),
 		router.NewGetRoute("/plugins/privileges", r.getPrivileges),
 		router.NewDeleteRoute("/plugins/{name:.*}", r.removePlugin),
-		router.NewPostRoute("/plugins/{name:.*}/enable", r.enablePlugin), // PATCH?
+		router.NewPostRoute("/plugins/{name:.*}/enable", r.enablePlugin),
 		router.NewPostRoute("/plugins/{name:.*}/disable", r.disablePlugin),
-		router.NewPostRoute("/plugins/pull", r.pullPlugin, router.WithCancel),
-		router.NewPostRoute("/plugins/{name:.*}/push", r.pushPlugin, router.WithCancel),
-		router.NewPostRoute("/plugins/{name:.*}/upgrade", r.upgradePlugin, router.WithCancel),
+		router.NewPostRoute("/plugins/pull", r.pullPlugin),
+		router.NewPostRoute("/plugins/{name:.*}/push", r.pushPlugin),
+		router.NewPostRoute("/plugins/{name:.*}/upgrade", r.upgradePlugin),
 		router.NewPostRoute("/plugins/{name:.*}/set", r.setPlugin),
 		router.NewPostRoute("/plugins/create", r.createPlugin),
 	}

api/server/router/swarm/cluster.go

@@ -37,7 +37,7 @@ func (sr *swarmRouter) initRoutes() {
 		router.NewPostRoute("/services/create", sr.createService),
 		router.NewPostRoute("/services/{id}/update", sr.updateService),
 		router.NewDeleteRoute("/services/{id}", sr.removeService),
-		router.NewGetRoute("/services/{id}/logs", sr.getServiceLogs, router.WithCancel),
+		router.NewGetRoute("/services/{id}/logs", sr.getServiceLogs),
 
 		router.NewGetRoute("/nodes", sr.getNodes),
 		router.NewGetRoute("/nodes/{id}", sr.getNode),
@@ -46,7 +46,7 @@ func (sr *swarmRouter) initRoutes() {
 
 		router.NewGetRoute("/tasks", sr.getTasks),
 		router.NewGetRoute("/tasks/{id}", sr.getTask),
-		router.NewGetRoute("/tasks/{id}/logs", sr.getTaskLogs, router.WithCancel),
+		router.NewGetRoute("/tasks/{id}/logs", sr.getTaskLogs),
 
 		router.NewGetRoute("/secrets", sr.getSecrets),
 		router.NewPostRoute("/secrets/create", sr.createSecret),

api/server/router/system/system.go

@@ -30,10 +30,10 @@ func NewRouter(b Backend, c ClusterBackend, fscache *fscache.FSCache, builder *b
 	r.routes = []router.Route{
 		router.NewOptionsRoute("/{anyroute:.*}", optionsHandler),
 		router.NewGetRoute("/_ping", r.pingHandler),
-		router.NewGetRoute("/events", r.getEvents, router.WithCancel),
+		router.NewGetRoute("/events", r.getEvents),
 		router.NewGetRoute("/info", r.getInfo),
 		router.NewGetRoute("/version", r.getVersion),
-		router.NewGetRoute("/system/df", r.getDiskUsage, router.WithCancel),
+		router.NewGetRoute("/system/df", r.getDiskUsage),
 		router.NewPostRoute("/auth", r.postAuth),
 	}
 

api/server/router/volume/volume.go

@@ -29,7 +29,7 @@ func (r *volumeRouter) initRoutes() {
 		router.NewGetRoute("/volumes/{name:.*}", r.getVolumeByName),
 		// POST
 		router.NewPostRoute("/volumes/create", r.postVolumesCreate),
-		router.NewPostRoute("/volumes/prune", r.postVolumesPrune, router.WithCancel),
+		router.NewPostRoute("/volumes/prune", r.postVolumesPrune),
 		// DELETE
 		router.NewDeleteRoute("/volumes/{name:.*}", r.deleteVolumes),
 	}

api/server/server.go

@@ -129,7 +129,8 @@ func (s *Server) makeHTTPHandler(handler httputils.APIFunc) http.HandlerFunc {
 
 		// use intermediate variable to prevent "should not use basic type
 		// string as key in context.WithValue" golint errors
-		ctx := context.WithValue(context.Background(), dockerversion.UAStringKey{}, r.Header.Get("User-Agent"))
+		ctx := context.WithValue(r.Context(), dockerversion.UAStringKey{}, r.Header.Get("User-Agent"))
+		r = r.WithContext(ctx)
 		handlerFunc := s.handlerWithGlobalMiddlewares(handler)
 
 		vars := mux.Vars(r)