// run receives pubsub messages from Redis after establishing a connection.
// When a valid message is received it is broadcast to all connected websockets
func (rr *redisReceiver) run() {
conn := rr.pool.Get()
defer conn.Close()
psc := redis.PubSubConn{conn}
psc.Subscribe(CHANNEL)
for {
switch v := psc.Receive().(type) {
case redis.Message:
log.WithFields(log.Fields{
"channel": v.Channel,
"message": string(v.Data),
}).Println("Redis Message Received")
msg, err := validateMessage(v.Data)
if err != nil {
log.WithFields(log.Fields{
"err": err,
"data": v.Data,
"msg": msg,
}).Error("Error unmarshalling message from Redis")
continue
}
rr.broadcast(v.Data)
case redis.Subscription:
log.WithFields(log.Fields{
"channel": v.Channel,
"kind": v.Kind,
"count": v.Count,
}).Println("Redis Subscription Received")
case error:
log.WithField("err", v).Errorf("Error while subscribed to Redis channel %s", CHANNEL)
default:
log.WithField("v", v).Println("Unknown Redis receive during subscription")
}
}
}
// Applications can receive pushed messages from one goroutine and manage subscriptions from another goroutine.
func ExamplePubSubConn() {
c, err := dial()
if err != nil {
panic(err)
}
defer c.Close()
var wg sync.WaitGroup
wg.Add(2)
psc := redis.PubSubConn{Conn: c}
// This goroutine receives and prints pushed notifications from the server.
// The goroutine exits when the connection is unsubscribed from all
// channels or there is an error.
go func() {
defer wg.Done()
for {
switch n := psc.Receive().(type) {
case redis.Message:
fmt.Printf("Message: %s %s\n", n.Channel, n.Data)
case redis.PMessage:
fmt.Printf("PMessage: %s %s %s\n", n.Pattern, n.Channel, n.Data)
case redis.Subscription:
fmt.Printf("Subscription: %s %s %d\n", n.Kind, n.Channel, n.Count)
if n.Count == 0 {
return
}
case error:
fmt.Printf("error: %v\n", n)
return
}
}
}()
// This goroutine manages subscriptions for the connection.
go func() {
defer wg.Done()
psc.Subscribe("example")
psc.PSubscribe("p*")
// The following function calls publish a message using another
// connection to the Redis server.
publish("example", "hello")
publish("example", "world")
publish("pexample", "foo")
publish("pexample", "bar")
// Unsubscribe from all connections. This will cause the receiving
// goroutine to exit.
psc.Unsubscribe()
psc.PUnsubscribe()
}()
wg.Wait()
// Output:
// Subscription: subscribe example 1
// Subscription: psubscribe p* 2
// Message: example hello
// Message: example world
// PMessage: p* pexample foo
// PMessage: p* pexample bar
// Subscription: unsubscribe example 1
// Subscription: punsubscribe p* 0
}
func TestPushed(t *testing.T) {
pc, err := redis.DialTestDB()
if err != nil {
t.Fatalf("error connection to database, %v", err)
}
defer pc.Close()
nc, err := net.Dial("tcp", ":6379")
if err != nil {
t.Fatal(err)
}
defer nc.Close()
nc.SetReadDeadline(time.Now().Add(4 * time.Second))
c := redis.PubSubConn{Conn: redis.NewConn(nc, 0, 0)}
c.Subscribe("c1")
expectPushed(t, c, "Subscribe(c1)", redis.Subscription{Kind: "subscribe", Channel: "c1", Count: 1})
c.Subscribe("c2")
expectPushed(t, c, "Subscribe(c2)", redis.Subscription{Kind: "subscribe", Channel: "c2", Count: 2})
c.PSubscribe("p1")
expectPushed(t, c, "PSubscribe(p1)", redis.Subscription{Kind: "psubscribe", Channel: "p1", Count: 3})
c.PSubscribe("p2")
expectPushed(t, c, "PSubscribe(p2)", redis.Subscription{Kind: "psubscribe", Channel: "p2", Count: 4})
c.PUnsubscribe()
expectPushed(t, c, "Punsubscribe(p1)", redis.Subscription{Kind: "punsubscribe", Channel: "p1", Count: 3})
expectPushed(t, c, "Punsubscribe()", redis.Subscription{Kind: "punsubscribe", Channel: "p2", Count: 2})
pc.Do("PUBLISH", "c1", "hello")
expectPushed(t, c, "PUBLISH c1 hello", redis.Message{Channel: "c1", Data: []byte("hello")})
}
func expectPushed(t *testing.T, c redis.PubSubConn, message string, expected interface{}) {
actual := c.Receive()
if !reflect.DeepEqual(actual, expected) {
t.Errorf("%s = %v, want %v", message, actual, expected)
}
}