bake: allow text descriptions for targets

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

bake/bake.go

@@ -675,7 +675,8 @@ type Group struct {
 }
 
 type Target struct {
-	Name string `json:"-" hcl:"name,label" cty:"name"`
+	Name        string `json:"-" hcl:"name,label" cty:"name"`
+	Description string `json:"description,omitempty" hcl:"description,optional" cty:"description"`
 
 	// Inherits is the only field that cannot be overridden with --set
 	Inherits []string `json:"inherits,omitempty" hcl:"inherits,optional" cty:"inherits"`
@@ -823,6 +824,9 @@ func (t *Target) Merge(t2 *Target) {
 	if t2.Ulimits != nil { // merge
 		t.Ulimits = append(t.Ulimits, t2.Ulimits...)
 	}
+	if t2.Description != "" {
+		t.Description = t2.Description
+	}
 	t.Inherits = append(t.Inherits, t2.Inherits...)
 }
 

commands/bake.go

@@ -337,11 +337,16 @@ func runBake(ctx context.Context, dockerCli command.Cli, targets []string, in ba
 			}
 		} else {
 			if sep {
-				fmt.Fprintf(dockerCli.Out(), "\n\n")
+				fmt.Fprintln(dockerCli.Out())
 			} else {
 				sep = true
 			}
 			fmt.Fprintf(dockerCli.Out(), "%s\n", name)
+			if descr := tgts[name].Description; descr != "" {
+				fmt.Fprintf(dockerCli.Out(), "%s\n", descr)
+			}
+
+			fmt.Fprintln(dockerCli.Out())
 			if code, err := printResult(dockerCli.Out(), pf, res); err != nil {
 				fmt.Fprintf(dockerCli.Out(), "error: %v\n", err)
 				exitCode = 1

commands/build.go

@@ -890,7 +890,7 @@ func printResult(w io.Writer, f *controllerapi.PrintFunc, res map[string]string)
 			// but here we want to print the error in a way that's consistent with how
 			// the lint warnings are printed via the `lint.PrintLintViolations` function,
 			// which differs from the default error printing.
-			if f.Format != "json" {
+			if f.Format != "json" && len(lintResults.Warnings) > 0 {
 				fmt.Fprintln(w)
 			}
 			lintBuf := bytes.NewBuffer([]byte(lintResults.Error.Message + "\n"))