Add DB field to RedisOpt to specify redis db index

asynq.go

@@ -54,4 +54,7 @@ type taskMessage struct {
 type RedisOpt struct {
 	Addr     string
 	Password string
+
+	// DB specifies which redis database to select.
+	DB int
 }

background.go

@@ -20,7 +20,11 @@ type Background struct {
 
 // NewBackground returns a new Background instance.
 func NewBackground(numWorkers int, opt *RedisOpt) *Background {
-	client := redis.NewClient(&redis.Options{Addr: opt.Addr, Password: opt.Password})
+	client := redis.NewClient(&redis.Options{
+		Addr:     opt.Addr,
+		Password: opt.Password,
+		DB:       opt.DB,
+	})
 	rdb := newRDB(client)
 	poller := newPoller(rdb, 5*time.Second, []string{scheduled, retry})
 	processor := newProcessor(rdb, numWorkers, nil)

client.go

@@ -14,7 +14,11 @@ type Client struct {
 
 // NewClient creates and returns a new client.
 func NewClient(opt *RedisOpt) *Client {
-	client := redis.NewClient(&redis.Options{Addr: opt.Addr, Password: opt.Password})
+	client := redis.NewClient(&redis.Options{
+		Addr:     opt.Addr,
+		Password: opt.Password,
+		DB:       opt.DB,
+	})
 	return &Client{rdb: newRDB(client)}
 }