support metadata file with call flag for build and bake commands

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

commands/bake.go

@@ -252,14 +252,16 @@ func runBake(ctx context.Context, dockerCli command.Cli, targets []string, in ba
 	if progressMode != progressui.QuietMode && progressMode != progressui.RawJSONMode {
 		desktop.PrintBuildDetails(os.Stderr, printer.BuildRefs(), term)
 	}
-	if callFunc == nil && len(in.metadataFile) > 0 {
+	if len(in.metadataFile) > 0 {
 		dt := make(map[string]interface{})
 		for t, r := range resp {
 			dt[t] = decodeExporterResponse(r.ExporterResponse)
 		}
+		if callFunc == nil {
 			if warnings := printer.Warnings(); len(warnings) > 0 && confutil.MetadataWarningsEnabled() {
 				dt["buildx.build.warnings"] = warnings
 			}
+		}
 		if err := writeMetadataFile(in.metadataFile, dt); err != nil {
 			return err
 		}

commands/build.go

@@ -367,20 +367,23 @@ func runBuild(ctx context.Context, dockerCli command.Cli, options buildOptions)
 			return errors.Wrap(err, "writing image ID file")
 		}
 	}
+	if options.metadataFile != "" {
+		dt := decodeExporterResponse(resp.ExporterResponse)
+		if opts.PrintFunc == nil {
+			if warnings := printer.Warnings(); len(warnings) > 0 && confutil.MetadataWarningsEnabled() {
+				dt["buildx.build.warnings"] = warnings
+			}
+		}
+		if err := writeMetadataFile(options.metadataFile, dt); err != nil {
+			return err
+		}
+	}
 	if opts.PrintFunc != nil {
 		if exitcode, err := printResult(dockerCli.Out(), opts.PrintFunc, resp.ExporterResponse); err != nil {
 			return err
 		} else if exitcode != 0 {
 			os.Exit(exitcode)
 		}
-	} else if options.metadataFile != "" {
-		dt := decodeExporterResponse(resp.ExporterResponse)
-		if warnings := printer.Warnings(); len(warnings) > 0 && confutil.MetadataWarningsEnabled() {
-			dt["buildx.build.warnings"] = warnings
-		}
-		if err := writeMetadataFile(options.metadataFile, dt); err != nil {
-			return err
-		}
 	}
 	return nil
 }
@@ -731,9 +734,17 @@ func writeMetadataFile(filename string, dt interface{}) error {
 }
 
 func decodeExporterResponse(exporterResponse map[string]string) map[string]interface{} {
+	decFunc := func(k, v string) ([]byte, error) {
+		if k == "result.json" {
+			// result.json is part of metadata response for subrequests which
+			// is already a JSON object: https://github.com/moby/buildkit/blob/f6eb72f2f5db07ddab89ac5e2bd3939a6444f4be/frontend/dockerui/requests.go#L100-L102
+			return []byte(v), nil
+		}
+		return base64.StdEncoding.DecodeString(v)
+	}
 	out := make(map[string]interface{})
 	for k, v := range exporterResponse {
-		dt, err := base64.StdEncoding.DecodeString(v)
+		dt, err := decFunc(k, v)
 		if err != nil {
 			out[k] = v
 			continue

tests/bake.go

@@ -13,6 +13,7 @@ import (
 	"github.com/docker/buildx/bake"
 	"github.com/docker/buildx/util/gitutil"
 	"github.com/moby/buildkit/client"
+	"github.com/moby/buildkit/frontend/subrequests/lint"
 	"github.com/moby/buildkit/identity"
 	provenancetypes "github.com/moby/buildkit/solver/llbsolver/provenance/types"
 	"github.com/moby/buildkit/util/contentutil"
@@ -56,6 +57,7 @@ var bakeTests = []func(t *testing.T, sb integration.Sandbox){
 	testListVariables,
 	testBakeCallCheck,
 	testBakeCallCheckFlag,
+	testBakeCallMetadata,
 	testBakeMultiPlatform,
 }
 
@@ -1214,3 +1216,61 @@ target "another" {
 
 	require.Len(t, warnings, 1)
 }
+
+func testBakeCallMetadata(t *testing.T, sb integration.Sandbox) {
+	dockerfile := []byte(`
+frOM busybox as base
+cOpy Dockerfile .
+from scratch
+COPy --from=base \
+  /Dockerfile \
+  /
+	`)
+	bakefile := []byte(`
+target "default" {}
+`)
+	dir := tmpdir(
+		t,
+		fstest.CreateFile("docker-bake.hcl", bakefile, 0600),
+		fstest.CreateFile("Dockerfile", dockerfile, 0600),
+	)
+
+	cmd := buildxCmd(
+		sb,
+		withDir(dir),
+		withArgs("bake", "--call", "check,format=json", "--metadata-file", filepath.Join(dir, "md.json")),
+	)
+	stdout := bytes.Buffer{}
+	stderr := bytes.Buffer{}
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+	require.Error(t, cmd.Run(), stdout.String(), stderr.String())
+
+	var res map[string]any
+	require.NoError(t, json.Unmarshal(stdout.Bytes(), &res), stdout.String())
+	targets, ok := res["target"].(map[string]any)
+	require.True(t, ok)
+	def, ok := targets["default"].(map[string]any)
+	require.True(t, ok)
+	_, ok = def["build"]
+	require.True(t, ok)
+	check, ok := def["check"].(map[string]any)
+	require.True(t, ok)
+	warnings, ok := check["warnings"].([]any)
+	require.True(t, ok)
+	require.Len(t, warnings, 3)
+
+	dt, err := os.ReadFile(filepath.Join(dir, "md.json"))
+	require.NoError(t, err)
+
+	type mdT struct {
+		Default struct {
+			BuildRef   string           `json:"buildx.build.ref"`
+			ResultJSON lint.LintResults `json:"result.json"`
+		} `json:"default"`
+	}
+	var md mdT
+	require.NoError(t, json.Unmarshal(dt, &md), dt)
+	require.NotEmpty(t, md.Default.BuildRef)
+	require.Len(t, md.Default.ResultJSON.Warnings, 3)
+}

tests/build.go

@@ -1193,6 +1193,44 @@ FROM second AS binary
 
 		require.Equal(t, 1, len(res.Sources))
 	})
+
+	t.Run("check metadata", func(t *testing.T) {
+		dockerfile := []byte(`
+frOM busybox as base
+cOpy Dockerfile .
+from scratch
+COPy --from=base \
+  /Dockerfile \
+  /
+	`)
+		dir := tmpdir(
+			t,
+			fstest.CreateFile("Dockerfile", dockerfile, 0600),
+		)
+
+		cmd := buildxCmd(sb, withArgs("build", "--call=check,format=json", "--metadata-file", filepath.Join(dir, "md.json"), dir))
+		stdout := bytes.Buffer{}
+		stderr := bytes.Buffer{}
+		cmd.Stdout = &stdout
+		cmd.Stderr = &stderr
+		require.Error(t, cmd.Run(), stdout.String(), stderr.String())
+
+		var res lint.LintResults
+		require.NoError(t, json.Unmarshal(stdout.Bytes(), &res), stdout.String())
+		require.Len(t, res.Warnings, 3)
+
+		dt, err := os.ReadFile(filepath.Join(dir, "md.json"))
+		require.NoError(t, err)
+
+		type mdT struct {
+			BuildRef   string           `json:"buildx.build.ref"`
+			ResultJSON lint.LintResults `json:"result.json"`
+		}
+		var md mdT
+		require.NoError(t, json.Unmarshal(dt, &md), dt)
+		require.NotEmpty(t, md.BuildRef)
+		require.Len(t, md.ResultJSON.Warnings, 3)
+	})
 }
 
 func createTestProject(t *testing.T) string {