// 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 (s *Storage) PubSub(redis_server, redis_auth, node_name string) {
pool := &redis.Pool{
MaxIdle: 3,
IdleTimeout: 240 * time.Second,
Dial: func() (redis.Conn, error) {
c, err := redis.Dial("tcp", redis_server)
if err != nil {
return nil, err
}
if redis_auth != "" {
if _, err := c.Do("AUTH", redis_auth); err != nil {
c.Close()
return nil, err
}
}
return c, err
},
TestOnBorrow: func(c redis.Conn, t time.Time) error {
_, err := c.Do("PING")
return err
},
}
pubsub_channel := "solocounter"
if node_name == "" {
node_name = randomString()
}
go func() {
var conn redis.Conn
var psc redis.PubSubConn
__connect__ := func() {
conn = pool.Get()
psc = redis.PubSubConn{conn}
psc.Subscribe(pubsub_channel)
}
__connect__()
defer conn.Close()
for {
switch v := psc.Receive().(type) {
case redis.Message:
if v.Channel == pubsub_channel {
var entry RedisEntry
err := json.Unmarshal(v.Data, &entry)
if err != nil {
log.Println("[error][json][unmarshal] : " + err.Error())
} else {
if entry.Node != node_name {
if s.Verbose {
log.Printf("[push][redis] %s, %s, %d", entry.Path, entry.Address, entry.Time)
}
s.get(entry.Path).add(entry.Address, entry.Time)
}
}
}
case redis.Subscription:
fmt.Printf("%s: %s %d\n", v.Channel, v.Kind, v.Count)
case error:
switch v.Error() {
case fmt.Sprintf("dial tcp %s: connection refused", redis_server):
fallthrough
case "EOF":
log.Println("[error][redis][subscribe] : " + v.Error() + " -> will reconnect 1 second later")
time.Sleep(time.Second * REDIS_RECONNECT_INTERVAL)
__connect__()
default:
log.Println("[error][redis][subscribe] : " + v.Error())
}
}
}
}()
s.c = make(chan RedisEntry, CHAN_CAPACITY_REDIS_ENTRY)
go func() {
conn := pool.Get()
defer conn.Close()
for {
select {
case entry := <-s.c:
entry.Node = node_name
b, err := json.Marshal(entry)
if err != nil {
log.Println("[error][json][marshal] : " + err.Error())
} else {
_, err := conn.Do("PUBLISH", pubsub_channel, b)
if err != nil {
log.Println("[error][redis][publish] : " + err.Error())
}
}
}
}
}()
}
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)
}
}