Add graceful errors and graceful shutdowns

[joeyak]

This would have 3 parts.

1. Have the server send an error object to the client so the client can tell what an error message is.
   This can be a wrapper around errors.

type Something struct {
err Error
}
func (s *Something) HTML() { return "blah" + err.Error() }

2. Have the client send a ClientData object with a special type for name changing. The first successful name change means that the client can join the chat room, because it will be upgraded from a temporary connection. Apply this change to the /nick command too.

3. Have movie night shutdown gracefully on ctrl+c with sending an error message saying something along the lines of "The server has been shut down". The code below can be used to have a graceful shutdown, that if it takes too long, just stops.

sigintCh chan os.Signal = make(chan os.Signal)
...
func main() {
...
	go func() {
		<-sigintCh
		// Killswitch if takes too long
		go func() {
			wait := waitMs*time.Duration(count) + time.Second*5

			// Make a reasonable wait time to kill a program
			if wait > time.Second*20 {
				wait = time.Second * 20
			}

			time.Sleep(wait)
			fmt.Println("Had to force close of program because it took too long to close")
			os.Exit(3)
		}()

		// Close connections
		fmt.Printf("Closing %d connections\n", count)
		handler.close()
		os.Exit(2)
}()

[joeyak]

The closing of the client connections can be done in the handleInterrupt function in fac6e28

[joeyak]

Accidentally closed it

[zorchenhimer]

I was playing around with expanding the code that you had already written for this to include http.Server.Shutdown(). I'm not sure it's strictly needed, but it might be a good idea to use that.

Essentially, a function is registered to be called once server.Shutdown() is called that can handle closing non-http connections (ie, the websockets). I had it setup to call a new ChatRoom.Shutdown() function that simply closes all the websocket connections and disallows new joins. This could be used to send a message to the client before closing the connection.

I can push the branch that I made while testing if you want to have a look.

[joeyak]

sure push it. I'm interested what the change looks like. Also nice find.

[zorchenhimer]

Pushed the new branch: e879112

[zorchenhimer]

I was looking at this again the other day to see what it would take to finish this up. Shutting down the HTTP server is rather straight forward, however shutting down the RTMP server is a different story. It doesn't look like it's possible without handling packets manually, but I haven't been able to really dig into the library code all that much.

I may just say "screw it" for the RTMP server stuff for now and just focus on the HTTP component. I've been wanting to get this done so I can properly daemonize the server.