Thank you!
loop.create_task does exactly what I want. main uses another level of yield
from (as you explained). That way I don't use loop.run_until_complete
within main.
Here is my top-level code that integrates server task and client tasks and
runs them in one loop:
# create client
client = Client(...)
# schedule client
loop.create_task(main(client))
# create and schedule server
server_coro = asyncio.start_server(client.handle_leecher,
host='0.0.0.0', port=61328, loop=loop)
server = loop.run_until_complete(server_coro) # schedule it
try:
loop.run_forever()
except KeyboardInterrupt as e:
...
finally:
server.close()
loop.run_until_complete(server.wait_closed())
client.shutdown()
loop.close()
On Tuesday, December 1, 2015 at 11:46:35 AM UTC-5, Guido van Rossum wrote:
>
> Hi Leslie,
>
> This sounds like a cool project.
>
> I don't know how to answer #1 (maybe 0.0.0.0 would work?) but for #2,
> instead of using run_until_complete() you should probably use a combination
> of coroutines and tasks.
>
> Inside a coroutine, if you want to wait for another coroutine, use "yield
> from other_coroutine()". Since asyncio.wait() is also a coroutine you can
> use that too: "yield from asyncio.wait(coros)". If you have something you
> want to start without waiting for it, wrap it in a task and let go of it --
> it will run independently as long as your event loop is running. Start it
> with "loop.create_task(coro)" -- or if you have a list of them, use a
> for-loop ("for coro in coros: loop.create_task(coro)"). Don't use yield
> from in this case.
>
> You'll need a main coroutine to kick everything off. If that remains
> active and never returns until you want to exit the program, you can start
> it with loop.run_until_complete(main_coro()). If you want to just kick it
> off and let the other coroutines run free, you can start it with
> loop.create_task(main_coro()); loop.run_forever(). Hit ^C to stop.
>
> Good luck!
>
> --Guido
>
> On Mon, Nov 30, 2015 at 9:07 PM, Leslie Klein <[email protected]
> <javascript:>> wrote:
>
>> I am writing a BitTorrent client using asyncio and the Streams API. I'm
>> trying to work at the highest level possible.
>> I have the download part working (client opens a connection to peers
>> provided by tracker and downloads all pieces). Client can also upload
>> pieces to connected peers, if requested.
>>
>> Big Question: how to listen to incoming connections from peers that join
>> the swarm? The client running on a peer must be able to listen for incoming
>> connections and upload pieces.
>> I set up a server (following the documentation in 18.5.5.1).
>>
>> Question 1: I don't know what address to bind the server to. I get the
>> error message "[Errno 10049] ... the requested address is not valid in its
>> context"
>>
>> Question 2: I don't know how to integrate the server with the other tasks
>> that run concurrently in the loop. (I assume this can be done with 1 loop).
>>
>> # tasks that open all connections
>> tasks that are running until complete:
>> coros = [client.connect_to_peer(peer) for peer in
>> client.active_peers.values()]
>> loop.run_until_complete(asyncio.wait(coros))
>>
>> then...
>>
>> # tasks that get a single piece by getting blocks from multiple peers (if
>> possible)
>> coros = [client.get_piece(index, peer) for peer in peers]
>> loop.run_until_complete(asyncio.wait(coros))
>>
>> I can easily do the following (if I could answer Question 1), but it
>> doesn't seem right (since my program should be listening to incoming
>> connections, even before the client becomes a seeder.)
>>
>> After the client is a seeder, the program can start the server and the
>> handle_leecher coroutine handles incoming connections and handshakes.
>> Then the server runs forever and uploads pieces to the remote peers.
>>
>> Thanks.
>> Leslie
>>
>>
>>
>>
>>
>>
>
>
> --
> --Guido van Rossum (python.org/~guido)
>
