Add a sock argument to create_datagram_endpoint()

[gvanrossum]

A number of requests for customization of datagram endpoints would be better served by having a sock argument to create_datagram_endpoint(), similar to create_server() and create_connection(). Example:

http://bugs.python.org/issue25230
http://bugs.python.org/issue23972

[gvanrossum]

See PR #267

[basak]

Is this intended to cover listening as a server as well as connecting as a client? I'm not clear on how to use this to get a socket listening.

[basak]

(and to test the PR I need both ends)

[gvanrossum]

You don't connect or listen when using UDP (datagrams); those are TCP (streams) terms. You can send at any time using sendto() and whenever you receive something your protocol's datagram_received() is called. (There is a connect() for UDP sockets but it merely supplies a default address argument to sendto().)

[gvanrossum]

Try looking at examples/udp_echo.py in the asyncio project.

[basak]

Ah, thanks. I was failing to combine my understanding of Unix domain socket streams with Internet datagrams. I didn't realise I had to bind the "client" end to something too.

I've refactored my code to bind each end to a local name manually (using the bind() method on a socket.socket object) and then using sock against create_datagram_endpoint() works with #267. My "trivial" use case of JSON-RPC over Unix datagram sockets is now working perfectly, thanks!

Though I have learnt the lesson that I need to bind each client to a path, it does still save serialization/deserialization that I'd have to do on a stream socket.

Many thanks for asyncio. It makes so many things trivial again.

[gvanrossum]

You're welcome. (But are you sure you want to use datagrams for RPC?!?)

[gvanrossum]

Addressed by commit 1e4ab9f by Chris Laws.