// NewPeer creates and returns a new Peer for communicating with AMQP brokers.
func NewPeer(host string) (*Peer, error) {
conn, err := amqp.Dial("amqp://" + host)
if err != nil {
return nil, err
}
channel, err := conn.Channel()
if err != nil {
return nil, err
}
queue, err := channel.QueueDeclare(
broker.GenerateName(), // name
false, // not durable
false, // delete when unused
true, // exclusive
false, // no wait
nil, // arguments
)
if err != nil {
return nil, err
}
err = channel.ExchangeDeclare(
exchange, // name
"fanout", // type
false, // not durable
false, // auto-deleted
false, // internal
false, // no wait
nil, // arguments
)
if err != nil {
return nil, err
}
return &Peer{
conn: conn,
queue: queue,
channel: channel,
send: make(chan []byte),
errors: make(chan error, 1),
done: make(chan bool),
}, nil
}
// Subscribe prepares the peer to consume messages.
func (n *Peer) Subscribe() error {
consumer, err := nsq.NewConsumer(topic, broker.GenerateName(), nsq.NewConfig())
if err != nil {
return err
}
consumer.AddHandler(nsq.HandlerFunc(func(message *nsq.Message) error {
n.messages <- message.Body
return nil
}))
if err := consumer.ConnectToNSQD(n.host); err != nil {
return err
}
n.consumer = consumer
return nil
}
func NewPeer(host string) (*Peer, error) {
p := &Peer{}
p.client = amps.NewClient("client")
p.client.MessageHandler = p
p.client.ErrorHandler = p
err := p.client.Connect("localhost:5000")
for err != nil {
err = p.client.Connect("localhost:5000")
}
if err == nil {
p.wrchan = make(chan []byte, 4096)
p.readchan = make(chan []byte, 4096)
p.errchan = make(chan error)
p.wrmsg.Command = "p"
p.wrmsg.Topic = "queue"
} else {
fmt.Printf("PEER ERROR %s\n", err)
}
go func() {
for {
data := <-p.wrchan
p.wrmsg.Data = string(data)
err := p.client.Send(&p.wrmsg)
if err != nil {
break
}
}
}()
// logon
logonMessage := amps.Message{
Command: "logon",
AckType: "processed",
UserId: broker.GenerateName(),
}
p.client.Send(&logonMessage)
<-p.readchan
return p, nil
}
// Subscribe prepares the peer to consume messages.
func (c *Peer) Subscribe() error {
// Subscription names must start with a lowercase letter, end with a
// lowercase letter or number, and contain only lowercase letters, numbers,
// dashes, underscores or periods.
c.subscription = strings.ToLower(fmt.Sprintf("x%sx", broker.GenerateName()))
exists, err := pubsub.SubExists(c.context, c.subscription)
if err != nil {
return err
}
if exists {
return fmt.Errorf("Subscription %s already exists", c.subscription)
}
if err := pubsub.CreateSub(c.context, c.subscription, topic, 0, ""); err != nil {
return err
}
go c.ack()
go func() {
// TODO: Can we avoid using atomic flag?
for atomic.LoadInt32(&c.stopped) != stopped {
messages, err := pubsub.PullWait(c.context, c.subscription, bufferSize)
if err != nil {
// Timed out.
continue
}
ids := make([]string, len(messages))
for i, message := range messages {
ids[i] = message.AckID
c.messages <- message.Data
}
c.acks <- ids
}
}()
return nil
}