Manager: exposed version to CLI (-version) and status reports

Now the / url shows the version of Flamenco Manager that is running,
and 'flamenco-manager -version' shows that too (then stops).

packages/flamenco-manager-go/src/flamenco-manager/flamenco/documents.go

@@ -107,3 +107,9 @@ type MayKeepRunningResponse struct {
 type SettingsInMongo struct {
 	DepsgraphLastModified *time.Time `bson:"depsgraph_last_modified"`
 }
+
+type StatusReport struct {
+	NrOfWorkers int    `json:"nr_of_workers"`
+	NrOfTasks   int    `json:"nr_of_tasks"`
+	Version     string `json:"version"`
+}

packages/flamenco-manager-go/src/flamenco-manager/flamenco/statusreport.go

@@ -9,15 +9,11 @@ import (
 	mgo "gopkg.in/mgo.v2"
 )
 
-type StatusReport struct {
-	NrOfWorkers int `json:"nr_of_workers"`
-	NrOfTasks   int `json:"nr_of_tasks"`
-}
-
 /**
  * Reports the status of the manager in JSON.
  */
-func SendStatusReport(w http.ResponseWriter, r *http.Request, session *mgo.Session) {
+func SendStatusReport(w http.ResponseWriter, r *http.Request, session *mgo.Session,
+	flamenco_version string) {
 	log.Info(r.RemoteAddr, "Status request received")
 
 	mongo_sess := session.Copy()
@@ -42,6 +38,7 @@ func SendStatusReport(w http.ResponseWriter, r *http.Request, session *mgo.Sessi
 	statusreport := StatusReport{
 		worker_count,
 		task_count,
+		flamenco_version,
 	}
 
 	encoder := json.NewEncoder(w)

packages/flamenco-manager-go/src/flamenco-manager/main.go

@@ -32,7 +32,7 @@ var task_update_pusher *flamenco.TaskUpdatePusher
 var task_timeout_checker *flamenco.TaskTimeoutChecker
 
 func http_status(w http.ResponseWriter, r *http.Request) {
-	flamenco.SendStatusReport(w, r, session)
+	flamenco.SendStatusReport(w, r, session, FLAMENCO_VERSION)
 }
 
 func http_register_worker(w http.ResponseWriter, r *http.Request) {
@@ -124,6 +124,7 @@ var cliArgs struct {
 	debug      bool
 	jsonLog    bool
 	cleanSlate bool
+	version    bool
 }
 
 func parseCliArgs() {
@@ -131,6 +132,7 @@ func parseCliArgs() {
 	flag.BoolVar(&cliArgs.debug, "debug", false, "Enable debug-level logging")
 	flag.BoolVar(&cliArgs.jsonLog, "json", false, "Log in JSON format")
 	flag.BoolVar(&cliArgs.cleanSlate, "cleanslate", false, "Start with a clean slate; erases all tasks from the local MongoDB")
+	flag.BoolVar(&cliArgs.version, "version", false, "Show the version of Flamenco Manager")
 	flag.Parse()
 }
 
@@ -155,6 +157,11 @@ func configLogging() {
 
 func main() {
 	parseCliArgs()
+	if cliArgs.version {
+		fmt.Println(FLAMENCO_VERSION)
+		return
+	}
+
 	configLogging()
 	log.Infof("Starting Flamenco Manager version %s", FLAMENCO_VERSION)