feat: add version data and display

main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"os"
 
 	"github.com/karrick/golf"
@@ -41,7 +42,7 @@ type (
 
 // Parse command line options.
 func parseCommandLine() tCliFlags {
-	var help bool
+	var help, version bool
 	flags := tCliFlags{}
 
 	golf.StringVarP(&flags.cfgFile, 'c', "config", "/etc/fetch-certificates.yml",
@@ -70,10 +71,17 @@ func parseCommandLine() tCliFlags {
 	golf.StringVarP(&flags.selector, 'u', "update", "*",
 		"LDAP DN of the certificate to select, or '*' to update all "+
 			"certificates.")
+	golf.BoolVarP(&version, 'v', "version", false, "Display version and exit.")
 
 	golf.Parse()
+	if version || help {
+		fmt.Println("fetchcert", versionString())
+	}
 	if help {
+		fmt.Println()
 		golf.Usage()
+	}
+	if version || help {
 		os.Exit(0)
 	}
 	return flags

version.go

@@ -0,0 +1,27 @@
+package main
+
+import "fmt"
+
+var (
+	version = ""
+	commit  = "unknown"
+	status  = ""
+	target  = "unknown/unknown"
+)
+
+func versionString() string {
+	var schar, ver string
+	if status == "dirty" {
+		schar = "*"
+	} else {
+		schar = ""
+	}
+
+	if version == "" {
+		ver = "development version"
+	} else {
+		ver = version
+	}
+
+	return fmt.Sprintf("%s (%s%s) %s", ver, commit, schar, target)
+}