Allow GateKeeper to be optional (#9)

src/go/cmd/strelka-frontend/main.go

@@ -34,7 +34,7 @@ type gate struct {
 
 type server struct {
 	coordinator coord
-	gatekeeper  gate
+	gatekeeper  *gate
 	responses   chan<- *strelka.ScanResponse
 }
 
@@ -107,7 +107,7 @@ func (s *server) ScanFile(stream strelka.Frontend_ScanFileServer) error {
 		Time:       time.Now().Unix(),
 	}
 
-	if req.Gatekeeper {
+	if req.Gatekeeper && s.gatekeeper != nil {
 		lrange := s.gatekeeper.cli.LRange(stream.Context(), sha, 0, -1).Val()
 		if len(lrange) > 0 {
 			for _, e := range lrange {
@@ -140,7 +140,7 @@ func (s *server) ScanFile(stream strelka.Frontend_ScanFileServer) error {
 	}
 
 	if err := s.coordinator.cli.ZAdd(
-	    stream.Context(),
+		stream.Context(),
 		"tasks",
 		&redis.Z{
 			Score:  float64(deadline.Unix()),
@@ -150,8 +150,12 @@ func (s *server) ScanFile(stream strelka.Frontend_ScanFileServer) error {
 		return err
 	}
 
-	tx := s.gatekeeper.cli.TxPipeline()
-	tx.Del(stream.Context(), sha)
+	var tx *redis.Pipeliner
+	if s.gatekeeper != nil {
+		pipeliner := s.gatekeeper.cli.TxPipeline()
+		tx = &pipeliner
+		(*tx).Del(stream.Context(), sha)
+	}
 
 	for {
 		lpop, err := s.coordinator.cli.LPop(stream.Context(), keye).Result()
@@ -163,7 +167,9 @@ func (s *server) ScanFile(stream strelka.Frontend_ScanFileServer) error {
 			break
 		}
 
-		tx.RPush(stream.Context(), sha, lpop)
+		if tx != nil {
+			(*tx).RPush(stream.Context(), sha, lpop)
+		}
 		if err := json.Unmarshal([]byte(lpop), &em); err != nil {
 			return err
 		}
@@ -184,9 +190,11 @@ func (s *server) ScanFile(stream strelka.Frontend_ScanFileServer) error {
 		}
 	}
 
-	tx.Expire(stream.Context(), sha, s.gatekeeper.ttl)
-	if _, err := tx.Exec(stream.Context()); err != nil {
-		return err
+	if tx != nil {
+		(*tx).Expire(stream.Context(), sha, s.gatekeeper.ttl)
+		if _, err := (*tx).Exec(stream.Context()); err != nil {
+			return err
+		}
 	}
 
 	return nil
@@ -245,26 +253,31 @@ func main() {
 		log.Fatalf("failed to connect to coordinator: %v", err)
 	}
 
-	gk := redis.NewClient(&redis.Options{
-		Addr:        conf.Gatekeeper.Addr,
-		DB:          conf.Gatekeeper.DB,
-		PoolSize:    conf.Gatekeeper.Pool,
-		ReadTimeout: conf.Gatekeeper.Read,
-	})
-	if err := gk.Ping(gk.Context()).Err(); err != nil {
-		log.Fatalf("failed to connect to gatekeeper: %v", err)
+	var gatekeeper *gate
+	if conf.Gatekeeper.Addr != "" {
+		gk := redis.NewClient(&redis.Options{
+			Addr:        conf.Gatekeeper.Addr,
+			DB:          conf.Gatekeeper.DB,
+			PoolSize:    conf.Gatekeeper.Pool,
+			ReadTimeout: conf.Gatekeeper.Read,
+		})
+		if err := gk.Ping(gk.Context()).Err(); err != nil {
+			log.Fatalf("failed to connect to gatekeeper: %v", err)
+		}
+
+		gatekeeper = &gate{
+			cli: gk,
+			ttl: conf.Gatekeeper.TTL,
+		}
 	}
 
 	s := grpc.NewServer()
 	opts := &server{
 		coordinator: coord{
 			cli: cd,
 		},
-		gatekeeper: gate{
-			cli: gk,
-			ttl: conf.Gatekeeper.TTL,
-		},
-		responses: responses,
+		gatekeeper: gatekeeper,
+		responses:  responses,
 	}
 
 	strelka.RegisterFrontendServer(s, opts)