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.
}
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")
flag.Usage()
os.Exit(1)
}
sentChan := make(chan electron.Outcome) // Channel to receive acknowledgements.
var wait sync.WaitGroup
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)) // Connctions to close on exit
// Start a goroutine for each URL to send messages.
for _, urlStr := range urls {
util.Debugf("Connecting to %v\n", urlStr)
go func(urlStr string) {
defer wait.Done() // Notify main() that 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)
util.ExitIf(err)
connections <- c // Save connection so we can Close() when main() ends
// Create a Sender using the path of the URL as the AMQP address
s, err := c.Sender(electron.Target(url.Path))
util.ExitIf(err)
// Loop sending messages.
for i := int64(0); i < *count; i++ {
m := amqp.NewMessage()
body := fmt.Sprintf("%v-%v", url.Path, i)
m.Marshal(body)
s.SendAsync(m, sentChan, body) // Outcome will be sent to sentChan
}
}(urlStr)
}
// Wait for all the acknowledgements
expect := int(*count) * len(urls)
util.Debugf("Started senders, expect %v acknowledgements\n", expect)
for i := 0; i < expect; i++ {
out := <-sentChan // Outcome of async sends.
if out.Error != nil {
util.Debugf("acknowledgement[%v] %v error: %v\n", i, out.Value, out.Error)
} else {
util.Debugf("acknowledgement[%v] %v (%v)\n", i, out.Value, out.Status)
}
}
fmt.Printf("Received all %v acknowledgements\n", expect)
wait.Wait() // Wait for all goroutines to finish.
close(connections)
for c := range connections { // Close all connections
if c != nil {
c.Close(nil)
}
}
}