Don't write pull output to stdout on container creating

Fixes #8632

Signed-off-by: Alexandr Morozov <lk4d4@docker.com>

api/client/commands.go

@@ -1986,6 +1986,10 @@ func (cli *DockerCli) CmdTag(args ...string) error {
 }
 
 func (cli *DockerCli) pullImage(image string) error {
+	return cli.pullImageCustomOut(image, cli.out)
+}
+
+func (cli *DockerCli) pullImageCustomOut(image string, out io.Writer) error {
 	v := url.Values{}
 	repos, tag := parsers.ParseRepositoryTag(image)
 	// pull only the image tagged 'latest' if no tag was specified
@@ -2014,7 +2018,7 @@ func (cli *DockerCli) pullImage(image string) error {
 	registryAuthHeader := []string{
 		base64.URLEncoding.EncodeToString(buf),
 	}
-	if err = cli.stream("POST", "/images/create?"+v.Encode(), nil, cli.out, map[string][]string{"X-Registry-Auth": registryAuthHeader}); err != nil {
+	if err = cli.stream("POST", "/images/create?"+v.Encode(), nil, out, map[string][]string{"X-Registry-Auth": registryAuthHeader}); err != nil {
 		return err
 	}
 	return nil
@@ -2081,7 +2085,8 @@ func (cli *DockerCli) createContainer(config *runconfig.Config, hostConfig *runc
 	if statusCode == 404 {
 		fmt.Fprintf(cli.err, "Unable to find image '%s' locally\n", config.Image)
 
-		if err = cli.pullImage(config.Image); err != nil {
+		// we don't want to write to stdout anything apart from container.ID
+		if err = cli.pullImageCustomOut(config.Image, cli.err); err != nil {
 			return nil, err
 		}
 		// Retry

integration-cli/docker_cli_run_test.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"bufio"
+	"bytes"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -2380,3 +2381,18 @@ func TestRunVolumesNotRecreatedOnStart(t *testing.T) {
 
 	logDone("run - volumes not recreated on start")
 }
+
+func TestRunNoOutputFromPullInStdout(t *testing.T) {
+	defer deleteAllContainers()
+	// just run with unknown image
+	cmd := exec.Command(dockerBinary, "run", "asdfsg")
+	stdout := bytes.NewBuffer(nil)
+	cmd.Stdout = stdout
+	if err := cmd.Run(); err == nil {
+		t.Fatal("Run with unknown image should fail")
+	}
+	if stdout.Len() != 0 {
+		t.Fatalf("Stdout contains output from pull: %s", stdout)
+	}
+	logDone("run - no output from pull in stdout")
+}