1 files changed, 172 insertions, 0 deletions
diff --git a/plugins/broadcast/redis/redis.go b/plugins/broadcast/redis/redis.go
new file mode 100644
index 00000000..41f48658
--- /dev/null
+++ b/plugins/broadcast/redis/redis.go
@@ -0,0 +1,172 @@
+package redis
+
+import (
+	"context"
+	"errors"
+	"sync/atomic"
+
+	"github.com/go-redis/redis/v8"
+)
+
+// Redis based broadcast Router.
+type Redis struct {
+	client        redis.UniversalClient
+	psClient      redis.UniversalClient
+	router        *Router
+	messages      chan *Message
+	listen, leave chan subscriber
+	stop          chan interface{}
+	stopped       int32
+}
+
+// creates new redis broker
+func redisBroker(cfg *RedisConfig) (*Redis, error) {
+	client := cfg.redisClient()
+	if _, err := client.Ping(context.Background()).Result(); err != nil {
+		return nil, err
+	}
+
+	psClient := cfg.redisClient()
+	if _, err := psClient.Ping(context.Background()).Result(); err != nil {
+		return nil, err
+	}
+
+	return &Redis{
+		client:   client,
+		psClient: psClient,
+		router:   NewRouter(),
+		messages: make(chan *Message),
+		listen:   make(chan subscriber),
+		leave:    make(chan subscriber),
+		stop:     make(chan interface{}),
+		stopped:  0,
+	}, nil
+}
+
+// Serve serves broker.
+func (r *Redis) Serve() error {
+	pubsub := r.psClient.Subscribe(context.Background())
+	channel := pubsub.Channel()
+
+	for {
+		select {
+		case ctx := <-r.listen:
+			ctx.done <- r.handleJoin(ctx, pubsub)
+		case ctx := <-r.leave:
+			ctx.done <- r.handleLeave(ctx, pubsub)
+		case msg := <-channel:
+			r.router.Dispatch(&Message{
+				Topic:   msg.Channel,
+				Payload: []byte(msg.Payload),
+			})
+		case <-r.stop:
+			return nil
+		}
+	}
+}
+
+func (r *Redis) handleJoin(sub subscriber, pubsub *redis.PubSub) error {
+	if sub.pattern != "" {
+		newPatterns, err := r.router.SubscribePattern(sub.upstream, sub.pattern)
+		if err != nil || len(newPatterns) == 0 {
+			return err
+		}
+
+		return pubsub.PSubscribe(context.Background(), newPatterns...)
+	}
+
+	newTopics := r.router.Subscribe(sub.upstream, sub.topics...)
+	if len(newTopics) == 0 {
+		return nil
+	}
+
+	return pubsub.Subscribe(context.Background(), newTopics...)
+}
+
+func (r *Redis) handleLeave(sub subscriber, pubsub *redis.PubSub) error {
+	if sub.pattern != "" {
+		dropPatterns := r.router.UnsubscribePattern(sub.upstream, sub.pattern)
+		if len(dropPatterns) == 0 {
+			return nil
+		}
+
+		return pubsub.PUnsubscribe(context.Background(), dropPatterns...)
+	}
+
+	dropTopics := r.router.Unsubscribe(sub.upstream, sub.topics...)
+	if len(dropTopics) == 0 {
+		return nil
+	}
+
+	return pubsub.Unsubscribe(context.Background(), dropTopics...)
+}
+
+// Stop closes the consumption and disconnects broker.
+func (r *Redis) Stop() {
+	if atomic.CompareAndSwapInt32(&r.stopped, 0, 1) {
+		close(r.stop)
+	}
+}
+
+// Subscribe broker to one or multiple channels.
+func (r *Redis) Subscribe(upstream chan *Message, topics ...string) error {
+	if atomic.LoadInt32(&r.stopped) == 1 {
+		return errors.New("broker has been stopped")
+	}
+
+	ctx := subscriber{upstream: upstream, topics: topics, done: make(chan error)}
+
+	r.listen <- ctx
+	return <-ctx.done
+}
+
+// SubscribePattern broker to pattern.
+func (r *Redis) SubscribePattern(upstream chan *Message, pattern string) error {
+	if atomic.LoadInt32(&r.stopped) == 1 {
+		return errors.New("broker has been stopped")
+	}
+
+	ctx := subscriber{upstream: upstream, pattern: pattern, done: make(chan error)}
+
+	r.listen <- ctx
+	return <-ctx.done
+}
+
+// Unsubscribe broker from one or multiple channels.
+func (r *Redis) Unsubscribe(upstream chan *Message, topics ...string) error {
+	if atomic.LoadInt32(&r.stopped) == 1 {
+		return errors.New("broker has been stopped")
+	}
+
+	ctx := subscriber{upstream: upstream, topics: topics, done: make(chan error)}
+
+	r.leave <- ctx
+	return <-ctx.done
+}
+
+// UnsubscribePattern broker from pattern.
+func (r *Redis) UnsubscribePattern(upstream chan *Message, pattern string) error {
+	if atomic.LoadInt32(&r.stopped) == 1 {
+		return errors.New("broker has been stopped")
+	}
+
+	ctx := subscriber{upstream: upstream, pattern: pattern, done: make(chan error)}
+
+	r.leave <- ctx
+	return <-ctx.done
+}
+
+// Publish one or multiple Channel.
+func (r *Redis) Publish(messages ...*Message) error {
+	if atomic.LoadInt32(&r.stopped) == 1 {
+		return errors.New("broker has been stopped")
+	}
+
+	for _, msg := range messages {
+		if err := r.client.Publish(context.Background(), msg.Topic, []byte(msg.Payload)).Err(); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}