Is there a class accept a socket?

I want to use asyncssh as server in a child process. Parent process use socketserver.ForkingTCPServer.

Like this:

server = socketserver.ForkingTCPServer((host, port), SSHHandler)
server.serve_forever()

class SSHHandler(socketserver.StreamRequestHandler)

    def handle(self):
        # accept a ssh socket, make a ssh connection and do something
        async_ssh_server(socket=self.request)

[ronf]

In order to take advantage of multiple processes, you’d need for each process to create its own aysncio event loop after it is forked, and to get maximum benefit from that you’d really want to create a pool of such processes of roughly the size of the number of CPU cores on the system. With the forking socket server, you’ll end up with a separate process for each connection, which can lead to performance problems if the number of connections is much larger than the number of available cores.

I must admit that I haven’t spent a lot of time trying to get Python asyncio working with a pool of processes. If you truly don’t need to share any state across connections, it’s actually probably easier to just run multiple instances of your server. You can allow multiple instances to listen on the same port if you add reuse_port=True to the arguments when setting up your AsyncSSH listener, and at least on Linux it seems like connections are automatically spread across your multiple processes when you do that. So, up front you’d fork off some number of processes based on available cores on your system and then for each child process you’d do something similar to the simple server link I listed above, but with reuse_port=True added.

One caveat to this: With I tried this on macOS, it seemed to always prefer the first listener you set up. Other processes can listen on the same port, but until the first listener is closed the other listeners won’t get any connections. So, if you need this to work on macOS, a different approach might be required where you pass an accepted socket between processes. There’s no portable way to do that in Python, though. Anything you did there would be end up being OS-specific, if it was possible at all.

[ghostbody]

That’s awesome, man!