Support init from existing config

cmd/hhfab/main.go

@@ -63,7 +63,7 @@ func main() {
 		Destination: &brief,
 	}
 
-	var basedir, preset, wiring, wiringGenType, wiringGenPreset string
+	var basedir, fromConfig, preset, wiring, wiringGenType, wiringGenPreset string
 	basedirFlag := &cli.StringFlag{
 		Name:        "basedir",
 		Aliases:     []string{"d"},
@@ -111,6 +111,12 @@ func main() {
 					basedirFlag,
 					verboseFlag,
 					briefFlag,
+					&cli.StringFlag{
+						Name:        "config",
+						Aliases:     []string{"c"},
+						Usage:       "start from existing config `FILE`",
+						Destination: &fromConfig,
+					},
 					&cli.StringFlag{
 						Name:        "preset",
 						Aliases:     []string{"p"},
@@ -137,13 +143,6 @@ func main() {
 					// 	Usage:       "use wiring diagram sample preset (one of: " + strings.Join(samplePresets, ", ") + ")",
 					// 	Destination: &wiringGenPreset,
 					// },
-					// TODO support loading from existing config
-					// &cli.StringFlag{
-					// 	Name:        "config",
-					// 	Aliases:     []string{"c"},
-					// 	Usage:       "start from existing config `FILE`",
-					// 	Destination: &config,
-					// },
 					// TODO support reset before init, is it really needed?
 					// &cli.BoolFlag{
 					// 	Name:        "reset",
@@ -155,7 +154,7 @@ func main() {
 					return setupLogger(verbose, brief)
 				},
 				Action: func(cCtx *cli.Context) error {
-					err := mngr.Init(basedir, cnc.Preset(preset), wiring, wiringGenType, wiringGenPreset)
+					err := mngr.Init(basedir, fromConfig, cnc.Preset(preset), wiring, wiringGenType, wiringGenPreset)
 					if err != nil {
 						return errors.Wrap(err, "error initializing")
 					}

pkg/fab/cnc/manager.go

@@ -10,7 +10,6 @@ import (
 	"regexp"
 	"time"
 
-	"github.com/davecgh/go-spew/spew"
 	"github.com/mholt/archiver/v4"
 	"github.com/pkg/errors"
 	"github.com/urfave/cli/v2"
@@ -124,13 +123,8 @@ func (mngr *Manager) prepare() error {
 	return nil
 }
 
-func (mngr *Manager) Init(basedir string, preset Preset, wiringPath string, wiringGenType string, wiringGenPreset string) error {
+func (mngr *Manager) Init(basedir string, fromConfig string, preset Preset, wiringPath string, wiringGenType string, wiringGenPreset string) error {
 	mngr.basedir = basedir
-	mngr.preset = preset
-
-	if !slices.Contains(mngr.presets, preset) {
-		return fmt.Errorf("unknown preset: %s", preset)
-	}
 
 	if wiringGenType == "" {
 		wiringGenType = "collapsedcore"
@@ -175,6 +169,24 @@ func (mngr *Manager) Init(basedir string, preset Preset, wiringPath string, wiri
 		return errors.New("wiring path or wiring gen must be specified")
 	}
 
+	if fromConfig != "" {
+		slog.Info("Loading existing config", "from", fromConfig)
+		err := mngr.loadConfig(fromConfig)
+		if err != nil {
+			return errors.Wrapf(err, "error existing loading config")
+		}
+
+		if mngr.preset != "" && preset != mngr.preset {
+			return errors.Errorf("loaded config preset mismatch: %s != %s", preset, mngr.preset)
+		}
+	}
+
+	mngr.preset = preset
+
+	if !slices.Contains(mngr.presets, preset) {
+		return fmt.Errorf("unknown preset: %s", preset)
+	}
+
 	err := mngr.prepare()
 	if err != nil {
 		return errors.Wrapf(err, "error preparing")
@@ -198,6 +210,25 @@ func (mngr *Manager) Save() error {
 		return errors.Wrapf(err, "error creating basedir %s", mngr.basedir)
 	}
 
+	data, err := mngr.configData()
+	if err != nil {
+		return errors.Wrapf(err, "error getting config data")
+	}
+
+	err = os.WriteFile(filepath.Join(mngr.basedir, "config.yaml"), data, 0o644)
+	if err != nil {
+		return errors.Wrapf(err, "error writing config")
+	}
+
+	err = mngr.wiring.SaveTo(filepath.Join(mngr.basedir, "wiring.yaml"))
+	if err != nil {
+		return errors.Wrapf(err, "error saving wiring")
+	}
+
+	return nil
+}
+
+func (mngr *Manager) configData() ([]byte, error) {
 	saver := &ManagerSaver{
 		Preset: mngr.preset,
 		Config: map[string]any{},
@@ -213,26 +244,14 @@ func (mngr *Manager) Save() error {
 
 	data, err := yaml.Marshal(saver)
 	if err != nil {
-		return errors.Wrapf(err, "error marshaling config")
-	}
-
-	err = os.WriteFile(filepath.Join(mngr.basedir, "config.yaml"), data, 0o644)
-	if err != nil {
-		return errors.Wrapf(err, "error writing config")
+		return nil, errors.Wrapf(err, "error marshaling config")
 	}
 
-	err = mngr.wiring.SaveTo(filepath.Join(mngr.basedir, "wiring.yaml"))
-	if err != nil {
-		return errors.Wrapf(err, "error saving wiring")
-	}
-
-	return nil
+	return data, nil
 }
 
-func (mngr *Manager) Load(basedir string) error {
-	mngr.basedir = basedir
-
-	data, err := os.ReadFile(filepath.Join(basedir, "config.yaml"))
+func (mngr *Manager) loadConfig(fromConfig string) error {
+	data, err := os.ReadFile(fromConfig)
 	if err != nil {
 		return errors.Wrapf(err, "error reading config")
 	}
@@ -262,6 +281,17 @@ func (mngr *Manager) Load(basedir string) error {
 		}
 	}
 
+	return nil
+}
+
+func (mngr *Manager) Load(basedir string) error {
+	mngr.basedir = basedir
+
+	err := mngr.loadConfig(filepath.Join(basedir, "config.yaml"))
+	if err != nil {
+		return errors.Wrapf(err, "error loading config")
+	}
+
 	wiringData, err := wiring.LoadDataFrom(filepath.Join(basedir, "wiring.yaml"))
 	if err != nil {
 		return errors.Wrapf(err, "error loading wiring")
@@ -536,9 +566,17 @@ func (adder *opAdder) addRunOp(bundle Bundle, stage Stage, name string, op RunOp
 }
 
 func (mngr *Manager) Dump() error {
-	slog.Info("Dumping")
+	slog.Info("Dumping hydrated config")
+
 	mngr.wiring = nil
-	spew.Dump(mngr)
+
+	data, err := mngr.configData()
+	if err != nil {
+		return errors.Wrapf(err, "error getting config data")
+	}
+
+	fmt.Println()
+	fmt.Println(string(data))
 
 	return nil
 }