Add version and git tag to binary

Fixes #47

Makefile

@@ -1,6 +1,10 @@
 TARGET = ./cc-backend
 VAR = ./var
 FRONTEND = ./web/frontend
+VERSION = 0.1
+GIT_HASH := $(shell git rev-parse --short HEAD || echo 'development')
+CURRENT_TIME = $(shell date +"%Y-%m-%d:T%H:%M:%S")
+LD_FLAGS = '-s -X main.buildTime=${CURRENT_TIME} -X main.version=${VERSION} -X main.hash=${GIT_HASH}'
 
 SVELTE_COMPONENTS = status   \
 					analysis \
@@ -25,7 +29,7 @@ SVELTE_SRC = $(wildcard $(FRONTEND)/src/*.svelte)         \
 
 $(TARGET): $(VAR) $(SVELTE_TARGETS)
 	$(info ===>  BUILD cc-backend)
-	@go build ./cmd/cc-backend
+	@go build -ldflags=${LD_FLAGS} ./cmd/cc-backend
 
 clean:
 	$(info ===>  CLEAN)

cmd/cc-backend/main.go

@@ -46,14 +46,30 @@ import (
 	_ "github.com/mattn/go-sqlite3"
 )
 
+const logoString = `
+ ____ _           _             ____           _          _ _   
+/ ___| |_   _ ___| |_ ___ _ __ / ___|___   ___| | ___ __ (_) |_ 
+| |   | | | | / __| __/ _ \ '__| |   / _ \ / __| |/ / '_ \| | __|
+| |___| | |_| \__ \ ||  __/ |  | |__| (_) | (__|   <| |_) | | |_ 
+\____|_|\__,_|___/\__\___|_|   \____\___/ \___|_|\_\ .__/|_|\__|
+                                                    |_|          
+`
+
+var (
+	buildTime string
+	hash      string
+	version   string
+)
+
 func main() {
-	var flagReinitDB, flagServer, flagSyncLDAP, flagGops, flagDev bool
+	var flagReinitDB, flagServer, flagSyncLDAP, flagGops, flagDev, flagVersion bool
 	var flagNewUser, flagDelUser, flagGenJWT, flagConfigFile, flagImportJob string
 	flag.BoolVar(&flagReinitDB, "init-db", false, "Go through job-archive and re-initialize the 'job', 'tag', and 'jobtag' tables (all running jobs will be lost!)")
 	flag.BoolVar(&flagSyncLDAP, "sync-ldap", false, "Sync the 'user' table with ldap")
 	flag.BoolVar(&flagServer, "server", false, "Start a server, continues listening on port after initialization and argument handling")
 	flag.BoolVar(&flagGops, "gops", false, "Listen via github.com/google/gops/agent (for debugging)")
 	flag.BoolVar(&flagDev, "dev", false, "Enable development components: GraphQL Playground and Swagger UI")
+	flag.BoolVar(&flagVersion, "version", false, "Show version information and exit")
 	flag.StringVar(&flagConfigFile, "config", "./config.json", "Specify alternative path to `config.json`")
 	flag.StringVar(&flagNewUser, "add-user", "", "Add a new user. Argument format: `<username>:[admin,support,api,user]:<password>`")
 	flag.StringVar(&flagDelUser, "del-user", "", "Remove user by `username`")
@@ -61,6 +77,14 @@ func main() {
 	flag.StringVar(&flagImportJob, "import-job", "", "Import a job. Argument format: `<path-to-meta.json>:<path-to-data.json>,...`")
 	flag.Parse()
 
+	if flagVersion {
+		fmt.Print(logoString)
+		fmt.Printf("Version:\t%s\n", version)
+		fmt.Printf("Git hash:\t%s\n", hash)
+		fmt.Printf("Build time:\t%s\n", buildTime)
+		os.Exit(0)
+	}
+
 	// See https://github.com/google/gops (Runtime overhead is almost zero)
 	if flagGops {
 		if err := agent.Listen(agent.Options{}); err != nil {