Provide "--version" command line parameter, keep version information.

.goreleaser.yaml

@@ -11,7 +11,12 @@ builds:
     goarch:
       - amd64
       - arm64
-    main: ./cmd/main.go
+    mod_timestamp: '{{ .CommitTimestamp }}'
+    flags:
+      - -trimpath
+    ldflags:
+      # Disables debug symbols (-s, -w), passes version information
+      - -s -w -X main.version={{.Version}} -X main.commit={{.Commit}} -X main.date={{ .CommitDate }}
 archives:
   - replacements:
       darwin: Darwin

cmd/main.go → cmd/app.go

@@ -1,4 +1,4 @@
-package main
+package cmd
 
 import (
 	"github.com/haimgel/mqtt2cmd/internal/config"
@@ -8,8 +8,8 @@ import (
 	"time"
 )
 
-func main() {
-	appConfig, err := config.Load()
+func Execute(version string, exit func(int), args []string) {
+	appConfig, err := config.Load(version, exit, args)
 	if err != nil {
 		panic(err)
 	}

internal/config/config.go

@@ -29,8 +29,8 @@ type ApplicationConfig struct {
 }
 
 // Load configuration from command-line options, config file, and environment variables
-func Load() (*ApplicationConfig, error) {
-	processCommandLineArguments()
+func Load(version string, exit func(int), args []string) (*ApplicationConfig, error) {
+	processCommandLineArguments(version, exit, args)
 
 	err := viper.BindPFlags(pflag.CommandLine)
 	if err != nil {
@@ -61,14 +61,19 @@ func Load() (*ApplicationConfig, error) {
 	return &config, nil
 }
 
-func processCommandLineArguments() {
+func processCommandLineArguments(versionStr string, exit func(int), args []string) {
 	pflag.StringP("mqtt.broker", "b", "", "MQTT broker (example \"tcp://hostname:1883\")")
 	pflag.StringP("log.path", "l", defaultLogFile(), "Log file path")
-	help := pflag.BoolP("help", "h", false, "")
-	pflag.Parse()
-	if *help {
+	helpFlag := pflag.BoolP("help", "h", false, "This help message")
+	versionFlag := pflag.BoolP("version", "v", false, "Show version")
+	_ = pflag.CommandLine.Parse(args)
+	if *helpFlag {
 		pflag.Usage()
-		os.Exit(2)
+		exit(2)
+	}
+	if *versionFlag {
+		fmt.Printf("%s version %s\n", AppName, versionStr)
+		exit(0)
 	}
 }
 

main.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"fmt"
+	"github.com/haimgel/mqtt2cmd/cmd"
+	"os"
+	"runtime"
+)
+
+// nolint: gochecknoglobals
+var (
+	version = "dev"
+	commit  = ""
+	date    = ""
+)
+
+func buildVersion(version, commit, date string) string {
+	result := version
+	if commit != "" {
+		result = fmt.Sprintf("%s\ncommit: %s", result, commit)
+	}
+	if date != "" {
+		result = fmt.Sprintf("%s\nbuilt at: %s", result, date)
+	}
+	result = fmt.Sprintf("%s\ngoos: %s\ngoarch: %s", result, runtime.GOOS, runtime.GOARCH)
+	return result
+}
+
+func main() {
+	cmd.Execute(
+		buildVersion(version, commit, date),
+		os.Exit,
+		os.Args[1:],
+	)
+}