SetReadDeadline and Concurrency

[rodicus]

Hi,

The Concurrency section of the documentation lists the read-related methods that should only be called by one routine. I am just wondering why SetReadDeadline is listed in there as it only seems to call the respective net.Conn method, which is supposedly safe for multi-routine use.

Thanks in advance,

Rod

[garyburd]

The SetReadDeadline method can be called concurrently in the current implementation.

Do you need to call it concurrently, and if so, why?

[rodicus]

I want to extend the read deadline on both, incoming application messages and pongs, and they happen to be handled on separate routines.

[garyburd]

Is there a reason why you cannot extend the deadline from the reading goroutine?

[rodicus]

I meant to say from the pong and reading routines. IIUC the websocket connection state can become permanently corrupted if a read op times out, so I am just trying to minimize that. However, I do want the connection to tell me something is wrong if I haven't heard from the client for a while either from pongs or regular messages.

[garyburd]

The pong handler is called from the reading goroutine and can set the deadline.

[rodicus]

I didn't realize the pong handler is called from advanceFrame which is itself called from reading methods. I assumed pongs and other control messages were received on a separate routine. Thanks for pointing that out.

[garyburd]

The overview documentation says:

The control message handler functions are called from the NextReader, ReadMessage and message reader Read methods.

I'll repeat this in the SetPing/Pong/CloseHandler documentation.

[rodicus]

I overlooked that (my bad). Adding the extra comment sounds great. Thanks Gary!