Merge pull request #15955 from aaronlehmann/parallel-pull-race-2

Fix race condition when waiting for a concurrent layer pull

integration-cli/docker_cli_pull_local_test.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"fmt"
+	"os/exec"
+	"strings"
 
 	"github.com/go-check/check"
 )
@@ -37,3 +39,134 @@ func (s *DockerRegistrySuite) TestPullImageWithAliases(c *check.C) {
 		}
 	}
 }
+
+// TestConcurrentPullWholeRepo pulls the same repo concurrently.
+func (s *DockerRegistrySuite) TestConcurrentPullWholeRepo(c *check.C) {
+	repoName := fmt.Sprintf("%v/dockercli/busybox", privateRegistryURL)
+
+	repos := []string{}
+	for _, tag := range []string{"recent", "fresh", "todays"} {
+		repo := fmt.Sprintf("%v:%v", repoName, tag)
+		_, err := buildImage(repo, fmt.Sprintf(`
+		    FROM busybox
+		    ENTRYPOINT ["/bin/echo"]
+		    ENV FOO foo
+		    ENV BAR bar
+		    CMD echo %s
+		`, repo), true)
+		if err != nil {
+			c.Fatal(err)
+		}
+		dockerCmd(c, "push", repo)
+		repos = append(repos, repo)
+	}
+
+	// Clear local images store.
+	args := append([]string{"rmi"}, repos...)
+	dockerCmd(c, args...)
+
+	// Run multiple re-pulls concurrently
+	results := make(chan error)
+	numPulls := 3
+
+	for i := 0; i != numPulls; i++ {
+		go func() {
+			_, _, err := runCommandWithOutput(exec.Command(dockerBinary, "pull", "-a", repoName))
+			results <- err
+		}()
+	}
+
+	// These checks are separate from the loop above because the check
+	// package is not goroutine-safe.
+	for i := 0; i != numPulls; i++ {
+		err := <-results
+		c.Assert(err, check.IsNil, check.Commentf("concurrent pull failed with error: %v", err))
+	}
+
+	// Ensure all tags were pulled successfully
+	for _, repo := range repos {
+		dockerCmd(c, "inspect", repo)
+		out, _ := dockerCmd(c, "run", "--rm", repo)
+		if strings.TrimSpace(out) != "/bin/sh -c echo "+repo {
+			c.Fatalf("CMD did not contain /bin/sh -c echo %s: %s", repo, out)
+		}
+	}
+}
+
+// TestConcurrentFailingPull tries a concurrent pull that doesn't succeed.
+func (s *DockerRegistrySuite) TestConcurrentFailingPull(c *check.C) {
+	repoName := fmt.Sprintf("%v/dockercli/busybox", privateRegistryURL)
+
+	// Run multiple pulls concurrently
+	results := make(chan error)
+	numPulls := 3
+
+	for i := 0; i != numPulls; i++ {
+		go func() {
+			_, _, err := runCommandWithOutput(exec.Command(dockerBinary, "pull", repoName+":asdfasdf"))
+			results <- err
+		}()
+	}
+
+	// These checks are separate from the loop above because the check
+	// package is not goroutine-safe.
+	for i := 0; i != numPulls; i++ {
+		err := <-results
+		if err == nil {
+			c.Fatal("expected pull to fail")
+		}
+	}
+}
+
+// TestConcurrentPullMultipleTags pulls multiple tags from the same repo
+// concurrently.
+func (s *DockerRegistrySuite) TestConcurrentPullMultipleTags(c *check.C) {
+	repoName := fmt.Sprintf("%v/dockercli/busybox", privateRegistryURL)
+
+	repos := []string{}
+	for _, tag := range []string{"recent", "fresh", "todays"} {
+		repo := fmt.Sprintf("%v:%v", repoName, tag)
+		_, err := buildImage(repo, fmt.Sprintf(`
+		    FROM busybox
+		    ENTRYPOINT ["/bin/echo"]
+		    ENV FOO foo
+		    ENV BAR bar
+		    CMD echo %s
+		`, repo), true)
+		if err != nil {
+			c.Fatal(err)
+		}
+		dockerCmd(c, "push", repo)
+		repos = append(repos, repo)
+	}
+
+	// Clear local images store.
+	args := append([]string{"rmi"}, repos...)
+	dockerCmd(c, args...)
+
+	// Re-pull individual tags, in parallel
+	results := make(chan error)
+
+	for _, repo := range repos {
+		go func(repo string) {
+			_, _, err := runCommandWithOutput(exec.Command(dockerBinary, "pull", repo))
+			results <- err
+		}(repo)
+	}
+
+	// These checks are separate from the loop above because the check
+	// package is not goroutine-safe.
+	for range repos {
+		err := <-results
+		c.Assert(err, check.IsNil, check.Commentf("concurrent pull failed with error: %v", err))
+	}
+
+	// Ensure all tags were pulled successfully
+	for _, repo := range repos {
+		dockerCmd(c, "inspect", repo)
+		out, _ := dockerCmd(c, "run", "--rm", repo)
+		if strings.TrimSpace(out) != "/bin/sh -c echo "+repo {
+			c.Fatalf("CMD did not contain /bin/sh -c echo %s: %s", repo, out)
+		}
+	}
+}