// Connect to addr and send/receive a message.
func client(addr net.Addr) {
if c, err := electron.Dial(addr.Network(), addr.String()); check("dial", err) {
defer c.Close(nil)
if s, err := c.Sender(electron.Target("target")); check("sender", err) {
fmt.Printf("client sending\n")
s.SendSync(amqp.NewMessageWith("hello")) // Send and wait for server to Accept()
}
if r, err := c.Receiver(electron.Source("source")); check("receiver", err) {
if rm, err := r.Receive(); err == nil {
fmt.Printf("client received %q\n", rm.Message.Body())
}
}
}
}
func main() {
flag.Usage = usage
flag.Parse()
urls := flag.Args() // Non-flag arguments are URLs to receive from
if len(urls) == 0 {
log.Println("No URL provided")
usage()
os.Exit(1)
}
messages := make(chan amqp.Message) // Channel for messages from goroutines to main()
defer close(messages)
var wait sync.WaitGroup // Used by main() to wait for all goroutines to end.
wait.Add(len(urls)) // Wait for one goroutine per URL.
_, prog := path.Split(os.Args[0])
container := electron.NewContainer(fmt.Sprintf("%v:%v", prog, os.Getpid()))
connections := make(chan electron.Connection, len(urls)) // Connections to close on exit
// Start a goroutine to for each URL to receive messages and send them to the messages channel.
// main() receives and prints them.
for _, urlStr := range urls {
util.Debugf("Connecting to %s\n", urlStr)
go func(urlStr string) { // Start the goroutine
defer wait.Done() // Notify main() when this goroutine is done.
url, err := amqp.ParseURL(urlStr) // Like net/url.Parse() but with AMQP defaults.
util.ExitIf(err)
// Open a new connection
conn, err := net.Dial("tcp", url.Host) // Note net.URL.Host is actually "host:port"
util.ExitIf(err)
c, err := container.Connection(conn)
connections <- c // Save connection so we can Close() when main() ends
// Create a Receiver using the path of the URL as the source address
r, err := c.Receiver(electron.Source(url.Path))
util.ExitIf(err)
// Loop receiving messages and sending them to the main() goroutine
for {
rm, err := r.Receive()
switch err {
case electron.Closed:
util.Debugf("closed %s", urlStr)
return
case nil:
messages <- rm.Message
default:
log.Fatal(err)
}
}
}(urlStr)
}
// All goroutines are started, we are receiving messages.
fmt.Printf("Listening on %d connections\n", len(urls))
// print each message until the count is exceeded.
for i := uint64(0); i < *count; i++ {
m := <-messages
util.Debugf("%s\n", util.FormatMessage(m))
}
fmt.Printf("Received %d messages\n", *count)
// Close all connections, this will interrupt goroutines blocked in Receiver.Receive()
for i := 0; i < len(urls); i++ {
c := <-connections
util.Debugf("close %s", c)
c.Close(nil)
}
wait.Wait() // Wait for all goroutines to finish.
}