builder: add graceful cancellation endpoint

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
Upstream-commit: 0bddd4ccfee5b7f4f69cd4757f053214be2ad4cd
Component: engine

components/engine/api/server/backend/build/backend.go

@@ -79,8 +79,10 @@ func (b *Backend) Build(ctx context.Context, config backend.BuildConfig) (string
 		}
 	}
 
-	stdout := config.ProgressWriter.StdoutFormatter
-	fmt.Fprintf(stdout, "Successfully built %s\n", stringid.TruncateID(imageID))
+	if !useBuildKit {
+		stdout := config.ProgressWriter.StdoutFormatter
+		fmt.Fprintf(stdout, "Successfully built %s\n", stringid.TruncateID(imageID))
+	}
 	err = tagger.TagImages(image.ID(imageID))
 	return imageID, err
 }
@@ -94,6 +96,10 @@ func (b *Backend) PruneCache(ctx context.Context) (*types.BuildCachePruneReport,
 	return &types.BuildCachePruneReport{SpaceReclaimed: size}, nil
 }
 
+func (b *Backend) Cancel(ctx context.Context, id string) error {
+	return b.buildkit.Cancel(ctx, id)
+}
+
 func squashBuild(build *builder.Result, imageComponent ImageComponent) (string, error) {
 	var fromID string
 	if build.FromImage != nil {

components/engine/api/server/router/build/backend.go

@@ -15,6 +15,8 @@ type Backend interface {
 
 	// Prune build cache
 	PruneCache(context.Context) (*types.BuildCachePruneReport, error)
+
+	Cancel(context.Context, string) error
 }
 
 type experimentalProvider interface {

components/engine/api/server/router/build/build.go

@@ -25,5 +25,6 @@ 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/cancel", r.postCancel),
 	}
 }

components/engine/api/server/router/build/build_routes.go

@@ -145,6 +145,7 @@ func newImageBuildOptions(ctx context.Context, r *http.Request) (*types.ImageBui
 		options.CacheFrom = cacheFrom
 	}
 	options.SessionID = r.FormValue("session")
+	options.BuildID = r.FormValue("buildid")
 
 	return options, nil
 }
@@ -157,6 +158,17 @@ func (br *buildRouter) postPrune(ctx context.Context, w http.ResponseWriter, r *
 	return httputils.WriteJSON(w, http.StatusOK, report)
 }
 
+func (br *buildRouter) postCancel(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
+	w.Header().Set("Content-Type", "application/json")
+
+	id := r.FormValue("id")
+	if id == "" {
+		return errors.Errorf("build ID not provided")
+	}
+
+	return br.backend.Cancel(ctx, id)
+}
+
 func (br *buildRouter) postBuild(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
 	var (
 		notVerboseBuffer = bytes.NewBuffer(nil)