tractor/tests/test_advanced_streaming.py

382 lines
9.7 KiB
Python

'''
Advanced streaming patterns using bidirectional streams and contexts.
'''
from collections import Counter
import itertools
import platform
from typing import Set, Dict, List
import trio
import tractor
def is_win():
return platform.system() == 'Windows'
_registry: Dict[str, Set[tractor.ReceiveMsgStream]] = {
'even': set(),
'odd': set(),
}
async def publisher(
seed: int = 0,
) -> None:
global _registry
def is_even(i):
return i % 2 == 0
for val in itertools.count(seed):
sub = 'even' if is_even(val) else 'odd'
for sub_stream in _registry[sub].copy():
await sub_stream.send(val)
# throttle send rate to ~1kHz
# making it readable to a human user
await trio.sleep(1/1000)
@tractor.context
async def subscribe(
ctx: tractor.Context,
) -> None:
global _registry
# syn caller
await ctx.started(None)
async with ctx.open_stream() as stream:
# update subs list as consumer requests
async for new_subs in stream:
new_subs = set(new_subs)
remove = new_subs - _registry.keys()
print(f'setting sub to {new_subs} for {ctx.chan.uid}')
# remove old subs
for sub in remove:
_registry[sub].remove(stream)
# add new subs for consumer
for sub in new_subs:
_registry[sub].add(stream)
async def consumer(
subs: List[str],
) -> None:
uid = tractor.current_actor().uid
async with tractor.wait_for_actor('publisher') as portal:
async with portal.open_context(subscribe) as (ctx, first):
async with ctx.open_stream() as stream:
# flip between the provided subs dynamically
if len(subs) > 1:
for sub in itertools.cycle(subs):
print(f'setting dynamic sub to {sub}')
await stream.send([sub])
count = 0
async for value in stream:
print(f'{uid} got: {value}')
if count > 5:
break
count += 1
else: # static sub
await stream.send(subs)
async for value in stream:
print(f'{uid} got: {value}')
def test_dynamic_pub_sub():
global _registry
from multiprocessing import cpu_count
cpus = cpu_count()
async def main():
async with tractor.open_nursery() as n:
# name of this actor will be same as target func
await n.run_in_actor(publisher)
for i, sub in zip(
range(cpus - 2),
itertools.cycle(_registry.keys())
):
await n.run_in_actor(
consumer,
name=f'consumer_{sub}',
subs=[sub],
)
# make one dynamic subscriber
await n.run_in_actor(
consumer,
name='consumer_dynamic',
subs=list(_registry.keys()),
)
# block until cancelled by user
with trio.fail_after(3):
await trio.sleep_forever()
try:
trio.run(main)
except trio.TooSlowError:
pass
@tractor.context
async def one_task_streams_and_one_handles_reqresp(
ctx: tractor.Context,
) -> None:
await ctx.started()
async with ctx.open_stream() as stream:
async def pingpong():
'''Run a simple req/response service.
'''
async for msg in stream:
print('rpc server ping')
assert msg == 'ping'
print('rpc server pong')
await stream.send('pong')
async with trio.open_nursery() as n:
n.start_soon(pingpong)
for _ in itertools.count():
await stream.send('yo')
await trio.sleep(0.01)
def test_reqresp_ontopof_streaming():
'''
Test a subactor that both streams with one task and
spawns another which handles a small requests-response
dialogue over the same bidir-stream.
'''
async def main():
# flat to make sure we get at least one pong
got_pong: bool = False
timeout: int = 2
if is_win(): # smh
timeout = 4
with trio.move_on_after(timeout):
async with tractor.open_nursery() as n:
# name of this actor will be same as target func
portal = await n.start_actor(
'dual_tasks',
enable_modules=[__name__]
)
async with portal.open_context(
one_task_streams_and_one_handles_reqresp,
) as (ctx, first):
assert first is None
async with ctx.open_stream() as stream:
await stream.send('ping')
async for msg in stream:
print(f'client received: {msg}')
assert msg in {'pong', 'yo'}
if msg == 'pong':
got_pong = True
await stream.send('ping')
print('client sent ping')
assert got_pong
try:
trio.run(main)
except trio.TooSlowError:
pass
async def async_gen_stream(sequence):
for i in sequence:
yield i
await trio.sleep(0.1)
@tractor.context
async def echo_ctx_stream(
ctx: tractor.Context,
) -> None:
await ctx.started()
async with ctx.open_stream() as stream:
async for msg in stream:
await stream.send(msg)
def test_sigint_both_stream_types():
'''Verify that running a bi-directional and recv only stream
side-by-side will cancel correctly from SIGINT.
'''
timeout: float = 2
if is_win(): # smh
timeout += 1
async def main():
with trio.fail_after(timeout):
async with tractor.open_nursery() as n:
# name of this actor will be same as target func
portal = await n.start_actor(
'2_way',
enable_modules=[__name__]
)
async with portal.open_context(echo_ctx_stream) as (ctx, _):
async with ctx.open_stream() as stream:
async with portal.open_stream_from(
async_gen_stream,
sequence=list(range(1)),
) as gen_stream:
msg = await gen_stream.receive()
await stream.send(msg)
resp = await stream.receive()
assert resp == msg
raise KeyboardInterrupt
try:
trio.run(main)
assert 0, "Didn't receive KBI!?"
except KeyboardInterrupt:
pass
@tractor.context
async def inf_streamer(
ctx: tractor.Context,
) -> None:
'''
Stream increasing ints until terminated with a 'done' msg.
'''
await ctx.started()
async with (
ctx.open_stream() as stream,
trio.open_nursery() as n,
):
async def bail_on_sentinel():
async for msg in stream:
if msg == 'done':
await stream.aclose()
else:
print(f'streamer received {msg}')
# start termination detector
n.start_soon(bail_on_sentinel)
for val in itertools.count():
try:
await stream.send(val)
except trio.ClosedResourceError:
# close out the stream gracefully
break
print('terminating streamer')
def test_local_task_fanout_from_stream():
'''
Single stream with multiple local consumer tasks using the
``MsgStream.subscribe()` api.
Ensure all tasks receive all values after stream completes sending.
'''
consumers = 22
async def main():
counts = Counter()
async with tractor.open_nursery() as tn:
p = await tn.start_actor(
'inf_streamer',
enable_modules=[__name__],
)
async with (
p.open_context(inf_streamer) as (ctx, _),
ctx.open_stream() as stream,
):
async def pull_and_count(name: str):
# name = trio.lowlevel.current_task().name
async with stream.subscribe() as recver:
assert isinstance(
recver,
tractor.trionics.BroadcastReceiver
)
async for val in recver:
# print(f'{name}: {val}')
counts[name] += 1
print(f'{name} bcaster ended')
print(f'{name} completed')
with trio.fail_after(3):
async with trio.open_nursery() as nurse:
for i in range(consumers):
nurse.start_soon(pull_and_count, i)
await trio.sleep(0.5)
print('\nterminating')
await stream.send('done')
print('closed stream connection')
assert len(counts) == consumers
mx = max(counts.values())
# make sure each task received all stream values
assert all(val == mx for val in counts.values())
await p.cancel_actor()
trio.run(main)