Add hint of progress to the output of docker build

This fix tries to address the issue raised in 24912 where docker
build only consists of the current step without overall total steps.

This fix adds the overall total steps so that end user could follow
the progress of the docker build.

An additonal test has been added to cover the changes.

This fix fixes 24912.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

builder/dockerfile/builder.go

@@ -226,6 +226,7 @@ func (b *Builder) build(stdout io.Writer, stderr io.Writer, out io.Writer) (stri
 	}
 
 	var shortImgID string
+	total := len(b.dockerfile.Children)
 	for i, n := range b.dockerfile.Children {
 		select {
 		case <-b.clientCtx.Done():
@@ -235,7 +236,7 @@ func (b *Builder) build(stdout io.Writer, stderr io.Writer, out io.Writer) (stri
 		default:
 			// Not cancelled yet, keep going...
 		}
-		if err := b.dispatch(i, n); err != nil {
+		if err := b.dispatch(i, total, n); err != nil {
 			if b.options.ForceRemove {
 				b.clearTmp()
 			}
@@ -312,8 +313,9 @@ func BuildFromConfig(config *container.Config, changes []string) (*container.Con
 	b.Stderr = ioutil.Discard
 	b.disableCommit = true
 
+	total := len(ast.Children)
 	for i, n := range ast.Children {
-		if err := b.dispatch(i, n); err != nil {
+		if err := b.dispatch(i, total, n); err != nil {
 			return nil, err
 		}
 	}

builder/dockerfile/evaluator.go

@@ -93,7 +93,7 @@ func init() {
 // such as `RUN` in ONBUILD RUN foo. There is special case logic in here to
 // deal with that, at least until it becomes more of a general concern with new
 // features.
-func (b *Builder) dispatch(stepN int, ast *parser.Node) error {
+func (b *Builder) dispatch(stepN int, stepTotal int, ast *parser.Node) error {
 	cmd := ast.Value
 	upperCasedCmd := strings.ToUpper(cmd)
 
@@ -107,7 +107,7 @@ func (b *Builder) dispatch(stepN int, ast *parser.Node) error {
 	original := ast.Original
 	flags := ast.Flags
 	strList := []string{}
-	msg := fmt.Sprintf("Step %d : %s", stepN+1, upperCasedCmd)
+	msg := fmt.Sprintf("Step %d/%d : %s", stepN+1, stepTotal, upperCasedCmd)
 
 	if len(ast.Flags) > 0 {
 		msg += " " + strings.Join(ast.Flags, " ")

builder/dockerfile/evaluator_test.go

@@ -182,7 +182,7 @@ func executeTestCase(t *testing.T, testCase dispatchTestCase) {
 
 	b := &Builder{runConfig: config, options: options, Stdout: ioutil.Discard, context: context}
 
-	err = b.dispatch(0, n.Children[0])
+	err = b.dispatch(0, len(n.Children), n.Children[0])
 
 	if err == nil {
 		t.Fatalf("No error when executing test %s", testCase.name)

builder/dockerfile/internals.go

@@ -432,6 +432,7 @@ func (b *Builder) processImageFrom(img builder.Image) error {
 			return err
 		}
 
+		total := len(ast.Children)
 		for i, n := range ast.Children {
 			switch strings.ToUpper(n.Value) {
 			case "ONBUILD":
@@ -440,7 +441,7 @@ func (b *Builder) processImageFrom(img builder.Image) error {
 				return fmt.Errorf("%s isn't allowed as an ONBUILD trigger", n.Value)
 			}
 
-			if err := b.dispatch(i, n); err != nil {
+			if err := b.dispatch(i, total, n); err != nil {
 				return err
 			}
 		}

integration-cli/docker_cli_build_test.go

@@ -5402,7 +5402,7 @@ func (s *DockerSuite) TestBuildNoDupOutput(c *check.C) {
 		c.Fatalf("Build should have worked: %q", err)
 	}
 
-	exp := "\nStep 2 : RUN env\n"
+	exp := "\nStep 2/2 : RUN env\n"
 	if !strings.Contains(out, exp) {
 		c.Fatalf("Bad output\nGot:%s\n\nExpected to contain:%s\n", out, exp)
 	}
@@ -5419,7 +5419,7 @@ func (s *DockerSuite) TestBuildStartsFromOne(c *check.C) {
 		c.Fatalf("Build should have worked: %q", err)
 	}
 
-	exp := "\nStep 1 : FROM busybox\n"
+	exp := "\nStep 1/1 : FROM busybox\n"
 	if !strings.Contains(out, exp) {
 		c.Fatalf("Bad output\nGot:%s\n\nExpected to contain:%s\n", out, exp)
 	}
@@ -6967,3 +6967,16 @@ func (s *DockerSuite) TestBuildCmdShellArgsEscaped(c *check.C) {
 		c.Fatalf("CMD was not escaped Config.Cmd: got %v", res)
 	}
 }
+
+// Test case for #24912.
+func (s *DockerSuite) TestBuildStepsWithProgress(c *check.C) {
+	name := "testbuildstepswithprogress"
+
+	totalRun := 5
+	_, out, err := buildImageWithOut(name, "FROM busybox\n"+strings.Repeat("RUN echo foo\n", totalRun), true)
+	c.Assert(err, checker.IsNil)
+	c.Assert(out, checker.Contains, fmt.Sprintf("Step 1/%d : FROM busybox", 1+totalRun))
+	for i := 2; i <= 1+totalRun; i++ {
+		c.Assert(out, checker.Contains, fmt.Sprintf("Step %d/%d : RUN echo foo", i, 1+totalRun))
+	}
+}