I'm new to goroutines and trying to work out the idiomatic way to organise this code. My program will generate async status events that I want to transmit to a server over a websocket. Right now I have a global channel messagesToServer to receive the status messages. The idea is it that will send the data if we currently have a websocket open, or quietly drop it if the connection to the server is currently closed or unavailable.
Relevant snippets are below. I don't really like the non-blocking send - if for some reason my writer goroutine took a while to process a message I think it could end up dropping a quick second message for no reason?
But if I use a blocking send, sendStatusToServer could block something that shouldn't be blocked if the connection is offline. I could try to track connected/disconnected state but if a message was sent at the same time as the disconnection occurred I think there would be a race condition.
Is there a tidy way I can write this?
var (
messagesToServer chan common.StationStatus
)
// ...
func sendStatusToServer(msg common.StationStatus) {
// Must be non-blocking in case we're not connected
select {
case messagesToServer <- msg:
break
default:
break
}
}
// ...
// after making websocket connection
log.Println("Connected to central server");
finished := make(chan struct{})
// Writer
go func() {
for {
select {
case msg := <-messagesToServer:
var buff bytes.Buffer
enc := gob.NewEncoder(&buff)
err = enc.Encode(msg)
conn.WriteMessage(websocket.BinaryMessage, buff.Bytes()); // ignore errors by design
case <-finished:
return;
}
}
}()
// Reader as busy loop on this goroutine
for {
messageType, p, err := conn.ReadMessage()
