Deflake docker in gVisor docker tests.

The docker client uses in the tests can catch the docker errors for commands
on the host's docker. However, when we start docker daemon inside a docker
container, the client can't catch the failure from the nested error message
from the docker daemon running inside.

To deflake the test, we always retry until we can get expected output from
execution logs in the command or timeout.

PiperOrigin-RevId: 825263678

Author: milantracy

test/image/image_test.go

@@ -599,6 +599,18 @@ func removeDockerImage(ctx context.Context, imageName string, d *dockerutil.Cont
 	return nil
 }
 
+func dockerInGvisorExecOutput(ctx context.Context, d *dockerutil.Container, cmd []string) (string, error) {
+	execProc, err := d.ExecProcess(ctx, dockerutil.ExecOpts{}, cmd...)
+	if err != nil {
+		return "", fmt.Errorf("docker exec failed: %v", err)
+	}
+	output, err := execProc.Logs()
+	if err != nil {
+		return "", fmt.Errorf("docker logs failed: %v", err)
+	}
+	return output, nil
+}
+
 func testDockerRun(ctx context.Context, t *testing.T, d *dockerutil.Container, opts dockerCommandOptions) {
 	cmd := []string{"docker", "run", "--rm"}
 	if opts.hostNetwork {
@@ -608,35 +620,44 @@ func testDockerRun(ctx context.Context, t *testing.T, d *dockerutil.Container, o
 		cmd = append(cmd, "--privileged")
 	}
 	cmd = append(cmd, testAlpineImage, "sh", "-c", "apk add curl && apk info -d curl")
-	execProc, err := d.ExecProcess(ctx, dockerutil.ExecOpts{}, cmd...)
-	if err != nil {
-		t.Fatalf("docker exec failed: %v", err)
-	}
-	output, err := execProc.Logs()
-	if err != nil {
-		t.Fatalf("docker logs failed: %v", err)
-	}
+
 	expectedOutput := "URL retrival utility and library"
-	if !strings.Contains(output, expectedOutput) {
-		t.Fatalf("docker didn't get output expected: %q, got: %q", expectedOutput, output)
+	output := ""
+	for i := 0; i < 5; i++ {
+		var err error
+		output, err = dockerInGvisorExecOutput(ctx, d, cmd)
+		if err != nil {
+			t.Fatalf("docker exec failed: %v", err)
+		}
+		if strings.Contains(output, expectedOutput) {
+			// The test passed, no more retries needed.
+			return
+		}
+		time.Sleep(1 * time.Second)
 	}
+	t.Fatalf("docker didn't get output expected: %q, got: %q", expectedOutput, output)
 }
 
 func testDockerBuild(ctx context.Context, t *testing.T, d *dockerutil.Container, opts dockerCommandOptions) {
-	parts := []string{"echo", fmt.Sprintf("\"FROM %s\nRUN apk add git\"", testAlpineImage), "|", "docker", "build"}
+	dockerfileRunCommand := "RUN apk add git"
+	parts := []string{"echo", fmt.Sprintf("\"FROM %s\n%s\"", testAlpineImage, dockerfileRunCommand), "|", "docker", "build"}
 	if opts.hostNetwork {
 		parts = append(parts, "--network", "host")
 	}
 	imageName := strings.ToLower(strings.ReplaceAll(testutil.RandomID("test_docker_build"), "/", "-"))
 	parts = append(parts, "-t", imageName, "-f", "-", ".")
 	cmd := strings.Join(parts, " ")
-	dockerBuildProc, err := d.ExecProcess(ctx, dockerutil.ExecOpts{}, "/bin/sh", "-c", cmd)
-	if err != nil {
-		t.Fatalf("docker exec failed: %v", err)
-	}
-	_, err = dockerBuildProc.Logs()
-	if err != nil {
-		t.Fatalf("docker logs failed: %v", err)
+	for i := 0; i < 5; i++ {
+		buildOutput, err := dockerInGvisorExecOutput(ctx, d, []string{"/bin/sh", "-c", cmd})
+		if err != nil {
+			t.Fatalf("docker exec failed: %v", err)
+		}
+		// The docker build output should container the Dockerfile's RUN commands.
+		if strings.Contains(buildOutput, dockerfileRunCommand) {
+			// The test passed, no more retries needed.
+			break
+		}
+		time.Sleep(1 * time.Second)
 	}
 	defer removeDockerImage(ctx, imageName, d)
 	if err := checkDockerImage(ctx, imageName, d); err != nil {
@@ -662,13 +683,9 @@ func testDockerExec(ctx context.Context, t *testing.T, d *dockerutil.Container,
 	}()
 
 	for i := 0; i < 10; i++ {
-		inspectProc, err := d.ExecProcess(ctx, dockerutil.ExecOpts{}, []string{"docker", "container", "inspect", containerName}...)
-		if err != nil {
-			t.Fatalf("docker container inspect failed: %v", err)
-		}
-		inspectOutput, err := inspectProc.Logs()
+		inspectOutput, err := dockerInGvisorExecOutput(ctx, d, []string{"docker", "container", "inspect", containerName})
 		if err != nil {
-			t.Fatalf("docker logs failed: %v", err)
+			t.Fatalf("docker exec failed: %v", err)
 		}
 		if strings.Contains(inspectOutput, "\"Status\": \"running\"") {
 			break
@@ -682,14 +699,10 @@ func testDockerExec(ctx context.Context, t *testing.T, d *dockerutil.Container,
 	}
 	// Execute echo command in the container.
 	execCmd = append(execCmd, containerName, "echo", "exec in "+containerName)
-	execProc, err := d.ExecProcess(ctx, dockerutil.ExecOpts{}, execCmd...)
-	if err != nil {
-		t.Fatalf("docker exec failed: %v", err)
-	}
 
-	output, err := execProc.Logs()
+	output, err := dockerInGvisorExecOutput(ctx, d, execCmd)
 	if err != nil {
-		t.Fatalf("docker logs failed: %v", err)
+		t.Fatalf("docker exec failed: %v", err)
 	}
 	expectedOutput := "exec in " + containerName
 	if !strings.Contains(output, expectedOutput) {