Add option for running catalyst-api as a stateless service (#1336)

From now on, we'll be able to run catalyst-api in 3 modes:
- all: the same as before
- cluster-only: managed MistUtilLoad and Serf only (intended to use inside Catalyst)
- api-only: stateless API only (intended to get deployed separately from Catalyst)

api/http_internal.go

@@ -84,56 +84,60 @@ func NewCatalystAPIRouterInternal(cli config.Cli, vodEngine *pipeline.Coordinato
 	// Simple endpoint for healthchecks
 	router.GET("/ok", withLogging(catalystApiHandlers.Ok()))
 
-	var metricsHandlers []http.Handler
-	if cli.ShouldMapic() {
-		metricsHandlers = append(metricsHandlers, mapic.MetricsHandler())
+	if cli.IsClusterMode() {
+		// Handler to get members Catalyst API => Catalyst
+		router.GET("/api/serf/members", withLogging(adminHandlers.MembersHandler()))
+		// Public handler to propagate an event to all Catalyst nodes, execute from Studio API => Catalyst
+		router.POST("/api/events", withLogging(eventsHandler.Events()))
 	}
-	if cli.MistPrometheus != "" {
-		// Enable Mist metrics enrichment
-		metricsHandlers = append(metricsHandlers, mapic.MistMetricsHandler())
-	}
-	metricsHandlers = append(metricsHandlers, promhttp.Handler())
-	// Hacky combined metrics handler. To be refactored away with mapic.
-	router.GET("/metrics", concatHandlers(metricsHandlers...))
-
-	// Public Catalyst API
-	router.POST("/api/vod",
-		withLogging(
-			withAuth(
-				cli.APIToken,
-				withCapacityChecking(
-					vodEngine,
-					catalystApiHandlers.UploadVOD(),
+
+	if cli.IsApiMode() {
+		var metricsHandlers []http.Handler
+		if cli.ShouldMapic() {
+			metricsHandlers = append(metricsHandlers, mapic.MetricsHandler())
+		}
+		if cli.MistPrometheus != "" {
+			// Enable Mist metrics enrichment
+			metricsHandlers = append(metricsHandlers, mapic.MistMetricsHandler())
+		}
+		metricsHandlers = append(metricsHandlers, promhttp.Handler())
+		// Hacky combined metrics handler. To be refactored away with mapic.
+		router.GET("/metrics", concatHandlers(metricsHandlers...))
+
+		// Public Catalyst API
+		router.POST("/api/vod",
+			withLogging(
+				withAuth(
+					cli.APIToken,
+					withCapacityChecking(
+						vodEngine,
+						catalystApiHandlers.UploadVOD(),
+					),
 				),
 			),
-		),
-	)
-
-	// Handler to get members Catalyst API => Catalyst
-	router.GET("/api/serf/members", withLogging(adminHandlers.MembersHandler()))
-	// Public handler to propagate an event to all Catalyst nodes, execute from Studio API => Catalyst
-	router.POST("/api/events", withLogging(eventsHandler.Events()))
+		)
 
-	// Handler to forward the user event from Catalyst => Catalyst API
-	router.POST("/api/serf/receiveUserEvent", withLogging(eventsHandler.ReceiveUserEvent()))
+		// Handler to forward the user event from Catalyst => Catalyst API
+		router.POST("/api/serf/receiveUserEvent", withLogging(eventsHandler.ReceiveUserEvent()))
 
-	// Public GET handler to retrieve the public key for vod encryption
-	router.GET("/api/pubkey", withLogging(encryptionHandlers.PublicKeyHandler()))
+		// Public GET handler to retrieve the public key for vod encryption
+		router.GET("/api/pubkey", withLogging(encryptionHandlers.PublicKeyHandler()))
 
-	// Endpoint to receive "Triggers" (callbacks) from Mist
-	router.POST("/api/mist/trigger", withLogging(mistCallbackHandlers.Trigger()))
+		// Endpoint to receive "Triggers" (callbacks) from Mist
+		router.POST("/api/mist/trigger", withLogging(mistCallbackHandlers.Trigger()))
 
-	// Handler for STREAM_SOURCE triggers
-	broker.OnStreamSource(geoHandlers.HandleStreamSource)
+		// Handler for STREAM_SOURCE triggers
+		broker.OnStreamSource(geoHandlers.HandleStreamSource)
 
-	// Handler for USER_NEW triggers
-	broker.OnUserNew(accessControlHandlers.HandleUserNew)
+		// Handler for USER_NEW triggers
+		broker.OnUserNew(accessControlHandlers.HandleUserNew)
 
-	// Handler for USER_END triggers.
-	broker.OnUserEnd(analyticsHandlers.HandleUserEnd)
+		// Handler for USER_END triggers.
+		broker.OnUserEnd(analyticsHandlers.HandleUserEnd)
 
-	// Endpoint to receive segments and manifests that ffmpeg produces
-	router.POST("/api/ffmpeg/:id/:filename", withLogging(ffmpegSegmentingHandlers.NewFile()))
+		// Endpoint to receive segments and manifests that ffmpeg produces
+		router.POST("/api/ffmpeg/:id/:filename", withLogging(ffmpegSegmentingHandlers.NewFile()))
+	}
 
 	return router
 }

config/cli.go

@@ -25,6 +25,7 @@ type Cli struct {
 	MistUser                  string
 	MistPassword              string
 	MistPrometheus            string
+	Mode                      string
 	MistPort                  int
 	MistConnectTimeout        time.Duration
 	MistStreamSource          string
@@ -72,6 +73,7 @@ type Cli struct {
 	KafkaPassword             string
 	AnalyticsKafkaTopic       string
 	SerfMembersEndpoint       string
+	CatalystApiURL            string
 
 	// mapping playbackId to value between 0.0 to 100.0
 	CdnRedirectPlaybackPct             map[string]float64
@@ -111,6 +113,14 @@ func (cli *Cli) ShouldMapic() bool {
 	return cli.APIServer != ""
 }
 
+func (cli *Cli) IsClusterMode() bool {
+	return cli.Mode == "cluster-only" || cli.Mode == "all"
+}
+
+func (cli *Cli) IsApiMode() bool {
+	return cli.Mode == "api-only" || cli.Mode == "all"
+}
+
 // Should we enable mist-cleanup script to run periodically and delete leaky shm?
 func (cli *Cli) ShouldMistCleanup() bool {
 	return cli.MistCleanup