Refactor CLI exit code and error handling

cmd/command.go

@@ -8,6 +8,11 @@ import (
 	lifx "git.kill0.net/chill9/lume"
 )
 
+const (
+	ExitSuccess = iota
+	ExitError
+)
+
 type Config struct {
 	AccessToken string               `toml:"access_token"`
 	Colors      map[string][]float32 `toml:"colors"`

cmd/help.go

@@ -25,8 +25,8 @@ func HelpCmd(args CmdArgs) (int, error) {
 	} else if len(argv) >= 1 {
 		subCmd, ok := commandRegistry[argv[0]]
 		if !ok {
-			fmt.Printf("unknown command: %s\n", argv[0])
-			return 1, nil
+			fmt.Printf("unknown commnnd: %s\n", argv[0])
+			return ExitError, nil
 		}
 
 		if subCmd.Use != "" {
@@ -38,7 +38,7 @@ func HelpCmd(args CmdArgs) (int, error) {
 		subCmd.Flags.PrintDefaults()
 	}
 
-	return 0, nil
+	return ExitSuccess, nil
 }
 
 func printHelp(commands map[string]Command) {

cmd/ls.go

@@ -23,8 +23,8 @@ func LsCmd(args CmdArgs) (int, error) {
 	selector := args.Flags.String("selector")
 	lights, err := c.ListLights(selector)
 	if err != nil {
-		return 1, err
+		return ExitError, err
 	}
 	PrintLights(lights)
-	return 0, nil
+	return ExitSuccess, nil
 }

cmd/lume/main.go

@@ -1,11 +1,16 @@
 package main
 
 import (
+	"fmt"
 	"os"
 
 	lumecmd "git.kill0.net/chill9/lume/cmd"
 )
 
 func main() {
-	os.Exit(lumecmd.Main(os.Args))
+	exitCode, err := lumecmd.Main(os.Args)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s\n", err)
+	}
+	os.Exit(exitCode)
 }

cmd/main.go

@@ -1,6 +1,7 @@
 package lumecmd
 
 import (
+	"errors"
 	"flag"
 	"fmt"
 	"os"
@@ -12,19 +13,19 @@ import (
 
 const lumercFile string = ".lumerc"
 
-func Main(args []string) int {
+func Main(args []string) (int, error) {
 	var config Config
+	var err error
 
 	configPath := getConfigPath()
 	if configPath == "" {
-		fmt.Println("fatal: ~/.lumerc was not found")
-		return 1
+		err = errors.New("fatal: ~/.lumerc was not found")
+		return ExitError, err
 	}
 
 	if _, err := toml.DecodeFile(configPath, &config); err != nil {
-		fmt.Printf("fatal: failed to parse %s\n", configPath)
-		fmt.Println(err)
-		return 1
+		err = fmt.Errorf("fatal: failed to parse %s", configPath)
+		return ExitError, err
 	}
 
 	envAccessToken := os.Getenv("LIFX_ACCESS_TOKEN")
@@ -33,8 +34,8 @@ func Main(args []string) int {
 	}
 
 	if config.AccessToken == "" {
-		fmt.Println("access token is not set")
-		return 1
+		err = errors.New("fatal: access token is not set")
+		return ExitError, err
 	}
 
 	flag.Parse()
@@ -50,8 +51,8 @@ func Main(args []string) int {
 
 	cmd, ok := GetCommand(command)
 	if !ok {
-		fmt.Printf("lume: '%s' is not lume command. See 'lume help'\n", command)
-		return 1
+		err = fmt.Errorf("lume: '%s' is not lume command. See 'lume help'", command)
+		return ExitError, err
 	}
 	fs := cmd.Flags
 	fs.Parse(args[2:])
@@ -59,9 +60,10 @@ func Main(args []string) int {
 	cmdArgs.Flags = Flags{FlagSet: fs}
 	exitCode, err := cmd.Func(cmdArgs)
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "fatal: %s\n", err)
+		err = fmt.Errorf("fatal: %s", err)
 	}
-	return exitCode
+
+	return exitCode, err
 }
 
 func getConfigPath() string {

cmd/poweroff.go

@@ -33,8 +33,8 @@ func PoweroffCmd(args CmdArgs) (int, error) {
 
 	r, err := c.SetState(selector, state)
 	if err != nil {
-		return 1, err
+		return ExitError, err
 	}
 	PrintResults(r.Results)
-	return 0, nil
+	return ExitSuccess, nil
 }

cmd/poweron.go

@@ -33,8 +33,8 @@ func PoweronCmd(args CmdArgs) (int, error) {
 
 	r, err := c.SetState(selector, state)
 	if err != nil {
-		return 1, err
+		return ExitError, err
 	}
 	PrintResults(r.Results)
-	return 0, nil
+	return ExitSuccess, nil
 }

cmd/setcolor.go

@@ -81,17 +81,17 @@ func SetColorCmd(args CmdArgs) (int, error) {
 	} else if rgbFlag != "" {
 		color, err := parseRGB(rgbFlag)
 		if err != nil {
-			return 1, err
+			return ExitError, err
 		}
 		state.Color = color
 	} else if name != "" {
 		hsb, ok := args.Config.Colors[name]
 		if !ok {
-			return 1, fmt.Errorf("%s is not a defined color", name)
+			return ExitError, fmt.Errorf("%s is not a defined color", name)
 		}
 		color, err := lifx.NewHSBColor(hsb[0], hsb[1], hsb[2])
 		if err != nil {
-			return 1, err
+			return ExitError, err
 		}
 		state.Color = color
 	}
@@ -111,12 +111,12 @@ func SetColorCmd(args CmdArgs) (int, error) {
 	r, err := c.SetState(selector, state)
 	if err != nil {
 		fmt.Printf("fatal: %s\n", err)
-		return 1, err
+		return ExitError, err
 	}
 
 	if !fast {
 		PrintResults(r.Results)
 	}
 
-	return 0, nil
+	return ExitSuccess, nil
 }

cmd/setstate.go

@@ -75,12 +75,12 @@ func SetStateCmd(args CmdArgs) (int, error) {
 
 	r, err := c.SetState(selector, state)
 	if err != nil {
-		return 1, err
+		return ExitError, err
 	}
 
 	if !fast {
 		PrintResults(r.Results)
 	}
 
-	return 0, nil
+	return ExitSuccess, nil
 }

cmd/setwhite.go

@@ -58,7 +58,7 @@ func SetWhiteCmd(args CmdArgs) (int, error) {
 		kelvin := args.Flags.Int16("kelvin")
 		color, err := lifx.NewWhite(kelvin)
 		if err != nil {
-			return 1, err
+			return ExitError, err
 		}
 		state.Color = color
 	}
@@ -68,7 +68,7 @@ func SetWhiteCmd(args CmdArgs) (int, error) {
 		name := args.Flags.String("name")
 		color, err := lifx.NewWhiteString(name)
 		if err != nil {
-			return 1, err
+			return ExitError, err
 		}
 		state.Color = color
 	}
@@ -93,12 +93,12 @@ func SetWhiteCmd(args CmdArgs) (int, error) {
 
 	r, err := c.SetState(selector, state)
 	if err != nil {
-		return 1, err
+		return ExitError, err
 	}
 
 	if !fast {
 		PrintResults(r.Results)
 	}
 
-	return 0, nil
+	return ExitSuccess, nil
 }

cmd/toggle.go

@@ -29,8 +29,8 @@ func ToggleCmd(args CmdArgs) (int, error) {
 	selector := args.Flags.String("selector")
 	r, err := c.Toggle(selector, duration)
 	if err != nil {
-		return 1, err
+		return ExitError, err
 	}
 	PrintResults(r.Results)
-	return 0, nil
+	return ExitSuccess, nil
 }