Cancel download of dependencies on failure

depot/containerstore/dependencymanager.go

@@ -3,6 +3,7 @@ package containerstore
 import (
 	"fmt"
 	"net/url"
+	"sync"
 	"time"
 
 	"code.cloudfoundry.org/bytefmt"
@@ -47,14 +48,20 @@ func (bm *dependencyManager) DownloadCachedDependencies(logger lager.Logger, mou
 	completed := 0
 	mountChan := make(chan *cachedBindMount, total)
 	errChan := make(chan error, total)
+	cancelChan := make(chan struct{}, 0)
 	bindMounts := NewBindMounts(total)
 
 	if total == 0 {
 		return bindMounts, nil
 	}
 
+	var wg sync.WaitGroup
+
 	for i := range mounts {
+		wg.Add(1)
 		go func(mount *executor.CachedDependency) {
+			defer wg.Done()
+
 			limiterStart := time.Now()
 			bm.downloadRateLimiter <- struct{}{}
 			limiterTime := time.Now().Sub(limiterStart)
@@ -64,7 +71,7 @@ func (bm *dependencyManager) DownloadCachedDependencies(logger lager.Logger, mou
 				<-bm.downloadRateLimiter
 			}()
 
-			cachedMount, err := bm.downloadCachedDependency(logger, mount, logConfig, metronClient)
+			cachedMount, err := bm.downloadCachedDependency(logger, mount, logConfig, metronClient, cancelChan)
 			if err != nil {
 				errChan <- err
 			} else {
@@ -76,6 +83,8 @@ func (bm *dependencyManager) DownloadCachedDependencies(logger lager.Logger, mou
 	for {
 		select {
 		case err := <-errChan:
+			close(cancelChan)
+			wg.Wait()
 			return bindMounts, err
 		case cachedMount := <-mountChan:
 			bindMounts.AddBindMount(cachedMount.CacheKey, cachedMount.BindMount)
@@ -87,7 +96,7 @@ func (bm *dependencyManager) DownloadCachedDependencies(logger lager.Logger, mou
 	}
 }
 
-func (bm *dependencyManager) downloadCachedDependency(logger lager.Logger, mount *executor.CachedDependency, logConfig executor.LogConfig, metronClient loggingclient.IngressClient) (*cachedBindMount, error) {
+func (bm *dependencyManager) downloadCachedDependency(logger lager.Logger, mount *executor.CachedDependency, logConfig executor.LogConfig, metronClient loggingclient.IngressClient, cancelChan <-chan struct{}) (*cachedBindMount, error) {
 	sourceName, tags := logConfig.GetSourceNameAndTagsForLogging()
 	if mount.LogSource != "" {
 		sourceName = mount.LogSource
@@ -114,7 +123,7 @@ func (bm *dependencyManager) downloadCachedDependency(logger lager.Logger, mount
 			Algorithm: mount.ChecksumAlgorithm,
 			Value:     mount.ChecksumValue,
 		},
-		nil,
+		cancelChan,
 	)
 	if err != nil {
 		logger.Error("failed-fetching-cache-dependency", err, lager.Data{"download-url": downloadURL.String(), "cache-key": mount.CacheKey})

depot/containerstore/dependencymanager_test.go

@@ -3,6 +3,7 @@ package containerstore_test
 import (
 	"errors"
 	"net/url"
+	"time"
 
 	"code.cloudfoundry.org/cacheddownloader"
 	"code.cloudfoundry.org/cacheddownloader/cacheddownloaderfakes"
@@ -37,6 +38,45 @@ var _ = Describe("DependencyManager", func() {
 		}
 	})
 
+	Context("when fetching one of the dependencies fails", func() {
+		var dependency2ReceivedCancel, dependency3ReceivedCancel bool
+
+		BeforeEach(func() {
+			dependencies = append(dependencies,
+				executor.CachedDependency{CacheKey: "cache-key-3", LogSource: "log-source-3", From: "https://example.com:8080/download-3", To: "/var/data/buildpack-3"},
+			)
+
+			cache.FetchAsDirectoryStub = func(logger lager.Logger, urlToFetch *url.URL, cacheKey string, checksum cacheddownloader.ChecksumInfoType, cancelChan <-chan struct{}) (dirPath string, size int64, err error) {
+				switch cacheKey {
+				case "cache-key-1":
+					time.Sleep(1 * time.Second)
+					return "", 0, errors.New("failed-to-fetch")
+				case "cache-key-2":
+					select {
+					case <-cancelChan:
+						dependency2ReceivedCancel = true
+						return "", 0, errors.New("canceled")
+					}
+				case "cache-key-3":
+					select {
+					case <-cancelChan:
+						dependency3ReceivedCancel = true
+						return "", 0, errors.New("canceled")
+					}
+				}
+				return "", 0, errors.New("unknown-cache-key")
+			}
+		})
+
+		It("stops downloading the rest of the dependencies", func() {
+			_, err := dependencyManager.DownloadCachedDependencies(logger, dependencies, logConfig, fakeClient)
+			Expect(err).To(HaveOccurred())
+			Expect(err).To(MatchError("failed-to-fetch"))
+			Expect(dependency2ReceivedCancel).To(BeTrue())
+			Expect(dependency3ReceivedCancel).To(BeTrue())
+		})
+	})
+
 	Context("when fetching all of the dependencies succeeds", func() {
 		var bindMounts containerstore.BindMounts