feat: register interactive with values from cli (#682)

I used to be able to do something like `./act_runner register --instance https://gitea.com --token testdcff --name test` on GitHub Actions Runners, but act_runner always asked me to enter instance, token etc. again and requiring me to use `--no-interactive` including passing everything per cli.

My idea was to extract the preset input of some stages to skip the prompt for this value if it is a non empty string. Labels is the only question that has been asked more than once if validation failed, in this case the error path have to unset the values of the input structure to not end in a non-interactive loop.

_I have written this initially for my own gitea runner, might be useful to everyone using the official runner as well_

Reviewed-on: https://gitea.com/gitea/act_runner/pulls/682
Reviewed-by: Lunny Xiao <[email protected]>
Co-authored-by: Christopher Homberger <[email protected]>
Co-committed-by: Christopher Homberger <[email protected]>

Author: ChristopherHX

internal/app/cmd/register.go

@@ -52,7 +52,7 @@ func runRegister(ctx context.Context, regArgs *registerArgs, configFile *string)
 			}
 		} else {
 			go func() {
-				if err := registerInteractive(ctx, *configFile); err != nil {
+				if err := registerInteractive(ctx, *configFile, regArgs); err != nil {
 					log.Fatal(err)
 					return
 				}
@@ -127,6 +127,22 @@ func validateLabels(ls []string) error {
 	return nil
 }
 
+func (r *registerInputs) stageValue(stage registerStage) string {
+	switch stage {
+	case StageInputInstance:
+		return r.InstanceAddr
+	case StageInputToken:
+		return r.Token
+	case StageInputRunnerName:
+		return r.RunnerName
+	case StageInputLabels:
+		if len(r.Labels) > 0 {
+			return strings.Join(r.Labels, ",")
+		}
+	}
+	return ""
+}
+
 func (r *registerInputs) assignToNext(stage registerStage, value string, cfg *config.Config) registerStage {
 	// must set instance address and token.
 	// if empty, keep current stage.
@@ -181,18 +197,33 @@ func (r *registerInputs) assignToNext(stage registerStage, value string, cfg *co
 
 		if validateLabels(r.Labels) != nil {
 			log.Infoln("Invalid labels, please input again, leave blank to use the default labels (for example, ubuntu-latest:docker://docker.gitea.com/runner-images:ubuntu-latest)")
+			r.Labels = nil
 			return StageInputLabels
 		}
 		return StageWaitingForRegistration
 	}
 	return StageUnknown
 }
 
-func registerInteractive(ctx context.Context, configFile string) error {
+func initInputs(regArgs *registerArgs) *registerInputs {
+	inputs := &registerInputs{
+		InstanceAddr: regArgs.InstanceAddr,
+		Token:        regArgs.Token,
+		RunnerName:   regArgs.RunnerName,
+		Ephemeral:    regArgs.Ephemeral,
+	}
+	regArgs.Labels = strings.TrimSpace(regArgs.Labels)
+	// command line flag.
+	if regArgs.Labels != "" {
+		inputs.Labels = strings.Split(regArgs.Labels, ",")
+	}
+	return inputs
+}
+
+func registerInteractive(ctx context.Context, configFile string, regArgs *registerArgs) error {
 	var (
 		reader = bufio.NewReader(os.Stdin)
 		stage  = StageInputInstance
-		inputs = new(registerInputs)
 	)
 
 	cfg, err := config.LoadDefault(configFile)
@@ -202,13 +233,17 @@ func registerInteractive(ctx context.Context, configFile string) error {
 	if f, err := os.Stat(cfg.Runner.File); err == nil && !f.IsDir() {
 		stage = StageOverwriteLocalConfig
 	}
+	inputs := initInputs(regArgs)
 
 	for {
-		printStageHelp(stage)
-
-		cmdString, err := reader.ReadString('\n')
-		if err != nil {
-			return err
+		cmdString := inputs.stageValue(stage)
+		if cmdString == "" {
+			printStageHelp(stage)
+			var err error
+			cmdString, err = reader.ReadString('\n')
+			if err != nil {
+				return err
+			}
 		}
 		stage = inputs.assignToNext(stage, strings.TrimSpace(cmdString), cfg)
 
@@ -255,25 +290,17 @@ func registerNoInteractive(ctx context.Context, configFile string, regArgs *regi
 	if err != nil {
 		return err
 	}
-	inputs := &registerInputs{
-		InstanceAddr: regArgs.InstanceAddr,
-		Token:        regArgs.Token,
-		RunnerName:   regArgs.RunnerName,
-		Labels:       defaultLabels,
-		Ephemeral:    regArgs.Ephemeral,
-	}
-	regArgs.Labels = strings.TrimSpace(regArgs.Labels)
-	// command line flag.
-	if regArgs.Labels != "" {
-		inputs.Labels = strings.Split(regArgs.Labels, ",")
-	}
+	inputs := initInputs(regArgs)
 	// specify labels in config file.
 	if len(cfg.Runner.Labels) > 0 {
 		if regArgs.Labels != "" {
 			log.Warn("Labels from command will be ignored, use labels defined in config file.")
 		}
 		inputs.Labels = cfg.Runner.Labels
 	}
+	if len(inputs.Labels) == 0 {
+		inputs.Labels = defaultLabels
+	}
 
 	if inputs.RunnerName == "" {
 		inputs.RunnerName, _ = os.Hostname()