Add version information and -v flag

main.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"fmt"
 	"log"
+	"os"
 
 	"github.com/boltdb/bolt"
 	"github.com/namsral/flag"
@@ -14,18 +16,25 @@ var (
 
 func main() {
 	var (
+		version bool
 		config  string
 		dbpath  string
 		baseurl string
 		bind    string
 	)
 
+	flag.BoolVar(&version, "v", false, "display version information")
 	flag.StringVar(&config, "config", "", "config file")
 	flag.StringVar(&dbpath, "dbpath", "urls.db", "Database path")
 	flag.StringVar(&baseurl, "baseurl", "", "Base URL for display purposes")
 	flag.StringVar(&bind, "bind", "0.0.0.0:8000", "[int]:<port> to bind to")
 	flag.Parse()
 
+	if version {
+		fmt.Printf("shorturl v%s", FullVersion())
+		os.Exit(0)
+	}
+
 	var err error
 	db, err = bolt.Open(dbpath, 0600, nil)
 	if err != nil {

version.go

@@ -0,0 +1,16 @@
+package main
+
+var (
+	// Version release version
+	Version = "0.0.1"
+
+	// Build will be overwritten automatically by the build system
+	Build = "-dev"
+
+	// GitCommit will be overwritten automatically by the build system
+	GitCommit = "HEAD"
+)
+
+func FullVersion() string {
+	return Version + Build + " (" + GitCommit + ")"
+}