Pipeline Planning

internal/app/app.go

@@ -178,24 +178,35 @@ func runBuildModule(ctx context) error {
 	return nil
 }
 
+type buildHAKOptions struct {
+	filteredHAKs []string
+	planOnly     bool
+}
+
 func runBuildHAKs(ctx context) error {
 	p, err := loadProject(ctx.cwd)
 	if err != nil {
 		return err
 	}
 
-	filteredHAKs, err := parseBuildHAKArgs(ctx.args[1:])
+	opts, err := parseBuildHAKArgs(ctx.args[1:])
 	if err != nil {
 		return err
 	}
-	p, err = p.CloneWithHAKNames(filteredHAKs)
+	p, err = p.CloneWithHAKNames(opts.filteredHAKs)
 	if err != nil {
 		return err
 	}
 
-	result, err := pipeline.BuildHAKsWithProgress(p, func(message string) {
+	progress := func(message string) {
 		fmt.Fprintf(ctx.stdout, "[build-haks] %s\n", message)
-	})
+	}
+	var result pipeline.BuildResult
+	if opts.planOnly {
+		result, err = pipeline.PlanHAKsWithProgress(p, progress)
+	} else {
+		result, err = pipeline.BuildHAKsWithProgress(p, progress)
+	}
 	if err != nil {
 		return err
 	}
@@ -209,32 +220,34 @@ func runBuildHAKs(ctx context) error {
 	return nil
 }
 
-func parseBuildHAKArgs(args []string) ([]string, error) {
+func parseBuildHAKArgs(args []string) (buildHAKOptions, error) {
+	opts := buildHAKOptions{}
 	if len(args) == 0 {
-		return nil, nil
+		return opts, nil
 	}
 
-	var filtered []string
 	for index := 0; index < len(args); index++ {
 		arg := args[index]
 		switch arg {
 		case "-h", "--help":
-			return nil, errors.New("usage: build-haks [--hak <hak-name> ...]")
+			return opts, errors.New("usage: build-haks [--hak <hak-name> ...] [--plan-only]")
 		case "--hak":
 			index++
 			if index >= len(args) {
-				return nil, errors.New("--hak requires a value")
+				return opts, errors.New("--hak requires a value")
 			}
-			filtered = append(filtered, args[index])
+			opts.filteredHAKs = append(opts.filteredHAKs, args[index])
+		case "--plan-only":
+			opts.planOnly = true
 		default:
 			if value, ok := parseInlineFlagValue(arg, "--hak"); ok {
-				filtered = append(filtered, value)
+				opts.filteredHAKs = append(opts.filteredHAKs, value)
 				continue
 			}
-			return nil, fmt.Errorf("unknown build-haks argument %q", arg)
+			return opts, fmt.Errorf("unknown build-haks argument %q", arg)
 		}
 	}
-	return filtered, nil
+	return opts, nil
 }
 
 func parseInlineFlagValue(arg, name string) (string, bool) {