Merge pull request #11430 from jfrazelle/export_outputflag

Modified `docker export` to allow an --output flag

integration-cli/docker_cli_export_import_test.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"os"
 	"os/exec"
 	"strings"
 	"testing"
@@ -47,3 +48,52 @@ func TestExportContainerAndImportImage(t *testing.T) {
 	logDone("export - export a container")
 	logDone("import - import an image")
 }
+
+// Used to test output flag in the export command
+func TestExportContainerWithOutputAndImportImage(t *testing.T) {
+	runCmd := exec.Command(dockerBinary, "run", "-d", "busybox", "true")
+	out, _, err := runCommandWithOutput(runCmd)
+	if err != nil {
+		t.Fatal("failed to create a container", out, err)
+	}
+
+	cleanedContainerID := stripTrailingCharacters(out)
+
+	inspectCmd := exec.Command(dockerBinary, "inspect", cleanedContainerID)
+	out, _, err = runCommandWithOutput(inspectCmd)
+	if err != nil {
+		t.Fatalf("output should've been a container id: %s %s ", cleanedContainerID, err)
+	}
+
+	exportCmd := exec.Command(dockerBinary, "export", "--output=testexp.tar", cleanedContainerID)
+	if out, _, err = runCommandWithOutput(exportCmd); err != nil {
+		t.Fatalf("failed to export container: %s, %v", out, err)
+	}
+
+	out, _, err = runCommandWithOutput(exec.Command("cat", "testexp.tar"))
+	if err != nil {
+		t.Fatal(out, err)
+	}
+
+	importCmd := exec.Command(dockerBinary, "import", "-", "repo/testexp:v1")
+	importCmd.Stdin = strings.NewReader(out)
+	out, _, err = runCommandWithOutput(importCmd)
+	if err != nil {
+		t.Fatalf("failed to import image: %s, %v", out, err)
+	}
+
+	cleanedImageID := stripTrailingCharacters(out)
+
+	inspectCmd = exec.Command(dockerBinary, "inspect", cleanedImageID)
+	if out, _, err = runCommandWithOutput(inspectCmd); err != nil {
+		t.Fatalf("output should've been an image id: %s, %v", out, err)
+	}
+
+	deleteContainer(cleanedContainerID)
+	deleteImages("repo/testexp:v1")
+
+	os.Remove("/tmp/testexp.tar")
+
+	logDone("export - export a container with output flag")
+	logDone("import - import an image with output flag")
+}