how to check if asyncio loop has any associated sockets - python-3.x

Question

asyncio.Task.all_tasks() gives a list of all tasks for an event loop, but I can't find anything similar for sockets, and in particular, datagram sockets associated with a loop?
The absence of sockets & tasks could then signal "end of life" for the loop.
The question is, in the following example, what to put in loop_not_empty() that makes it return False when the task set is empty and there are no associated sockets (ie after two seconds)
Example:
import asyncio
import socket
import threading
class Handler(asyncio.Protocol):
def connection_made(self, transport):
self.transport = transport
print("connection made")
def datagram_received(self, data, addr):
if data == b'die':
print("shutting down")
self.transport.abort()
#asyncio.coroutine
def sometask():
yield from asyncio.sleep(1)
print("task done")
def loop_not_empty(l):
# if asyncio.Task.all_tasks() == set() and WHAT_GOES_HERE
# return False
return True
def main():
a,b = socket.socketpair(socket.AF_UNIX, socket.SOCK_DGRAM)
l = asyncio.get_event_loop()
asyncio.ensure_future(sometask(), loop=l)
asyncio.ensure_future(l.create_datagram_endpoint(Handler, sock=a), loop=l)
threading.Timer(2, lambda: b.send(b'die')).start()
while loop_not_empty(l):
l.run_until_complete(asyncio.sleep(1, loop=l))
main()

Answer 1

Here is a solution that uses a simple class and asyncio.Event() to count the number of active jobs and signals the loop to stop when all jobs are done:
import asyncio
import random
class UseCounter:
def __init__(self, loop=None):
self.loop = loop
self.event = asyncio.Event(loop=loop)
self.n = 0 # The number of active jobs
def __enter__(self):
self.enter()
def __exit__(self, exc_type, exc_val, exc_tb):
self.exit()
def enter(self):
self.n += 1
def exit(self):
self.n -= 1
if self.n == 0:
self.event.set()
async def wait(self):
return await self.event.wait()
async def my_coroutine(counter, term):
with counter:
print("start", term)
n = random.uniform(0.2, 1.5)
await asyncio.sleep(n)
print("end", term)
loop = asyncio.get_event_loop()
counter = UseCounter(loop)
terms = ["apple", "banana", "melon"]
for term in terms:
asyncio.ensure_future(my_coroutine(counter, term))
loop.run_until_complete(counter.wait())
loop.close()
For your example above, add .enter() to connection_made() and .exit() to connection_lost().