tractor/tests/test_legacy_one_way_streami...

353 lines
10 KiB
Python

"""
Streaming via async gen api
"""
import time
from functools import partial
import platform
import trio
import tractor
import pytest
from conftest import tractor_test
def test_must_define_ctx():
with pytest.raises(TypeError) as err:
@tractor.stream
async def no_ctx():
pass
assert "no_ctx must be `ctx: tractor.Context" in str(err.value)
@tractor.stream
async def has_ctx(ctx):
pass
async def async_gen_stream(sequence):
for i in sequence:
yield i
await trio.sleep(0.1)
# block indefinitely waiting to be cancelled by ``aclose()`` call
with trio.CancelScope() as cs:
await trio.sleep_forever()
assert 0
assert cs.cancelled_caught
@tractor.stream
async def context_stream(
ctx: tractor.Context,
sequence
):
for i in sequence:
await ctx.send_yield(i)
await trio.sleep(0.1)
# block indefinitely waiting to be cancelled by ``aclose()`` call
with trio.CancelScope() as cs:
await trio.sleep(float('inf'))
assert 0
assert cs.cancelled_caught
async def stream_from_single_subactor(
arb_addr,
start_method,
stream_func,
):
"""Verify we can spawn a daemon actor and retrieve streamed data.
"""
# only one per host address, spawns an actor if None
async with tractor.open_nursery(
arbiter_addr=arb_addr,
start_method=start_method,
) as nursery:
async with tractor.find_actor('streamerd') as portals:
if not portals:
# no brokerd actor found
portal = await nursery.start_actor(
'streamerd',
enable_modules=[__name__],
)
seq = range(10)
with trio.fail_after(5):
async with portal.open_stream_from(
stream_func,
sequence=list(seq), # has to be msgpack serializable
) as stream:
# it'd sure be nice to have an asyncitertools here...
iseq = iter(seq)
ival = next(iseq)
async for val in stream:
assert val == ival
try:
ival = next(iseq)
except StopIteration:
# should cancel far end task which will be
# caught and no error is raised
await stream.aclose()
await trio.sleep(0.3)
# ensure EOC signalled-state translates
# XXX: not really sure this is correct,
# shouldn't it be a `ClosedResourceError`?
try:
await stream.__anext__()
except StopAsyncIteration:
# stop all spawned subactors
await portal.cancel_actor()
@pytest.mark.parametrize(
'stream_func', [async_gen_stream, context_stream]
)
def test_stream_from_single_subactor(arb_addr, start_method, stream_func):
"""Verify streaming from a spawned async generator.
"""
trio.run(
partial(
stream_from_single_subactor,
arb_addr,
start_method,
stream_func=stream_func,
),
)
# this is the first 2 actors, streamer_1 and streamer_2
async def stream_data(seed):
for i in range(seed):
yield i
# trigger scheduler to simulate practical usage
await trio.sleep(0.0001)
# this is the third actor; the aggregator
async def aggregate(seed):
"""Ensure that the two streams we receive match but only stream
a single set of values to the parent.
"""
async with tractor.open_nursery() as nursery:
portals = []
for i in range(1, 3):
# fork point
portal = await nursery.start_actor(
name=f'streamer_{i}',
enable_modules=[__name__],
)
portals.append(portal)
send_chan, recv_chan = trio.open_memory_channel(500)
async def push_to_chan(portal, send_chan):
async with send_chan:
async with portal.open_stream_from(
stream_data, seed=seed,
) as stream:
async for value in stream:
# leverage trio's built-in backpressure
await send_chan.send(value)
print(f"FINISHED ITERATING {portal.channel.uid}")
# spawn 2 trio tasks to collect streams and push to a local queue
async with trio.open_nursery() as n:
for portal in portals:
n.start_soon(push_to_chan, portal, send_chan.clone())
# close this local task's reference to send side
await send_chan.aclose()
unique_vals = set()
async with recv_chan:
async for value in recv_chan:
if value not in unique_vals:
unique_vals.add(value)
# yield upwards to the spawning parent actor
yield value
assert value in unique_vals
print("FINISHED ITERATING in aggregator")
await nursery.cancel()
print("WAITING on `ActorNursery` to finish")
print("AGGREGATOR COMPLETE!")
# this is the main actor and *arbiter*
async def a_quadruple_example():
# a nursery which spawns "actors"
async with tractor.open_nursery() as nursery:
seed = int(1e3)
pre_start = time.time()
portal = await nursery.start_actor(
name='aggregator',
enable_modules=[__name__],
)
start = time.time()
# the portal call returns exactly what you'd expect
# as if the remote "aggregate" function was called locally
result_stream = []
async with portal.open_stream_from(aggregate, seed=seed) as stream:
async for value in stream:
result_stream.append(value)
print(f"STREAM TIME = {time.time() - start}")
print(f"STREAM + SPAWN TIME = {time.time() - pre_start}")
assert result_stream == list(range(seed))
await portal.cancel_actor()
return result_stream
async def cancel_after(wait, arb_addr):
async with tractor.open_root_actor(arbiter_addr=arb_addr):
with trio.move_on_after(wait):
return await a_quadruple_example()
@pytest.fixture(scope='module')
def time_quad_ex(arb_addr, ci_env, spawn_backend):
if spawn_backend == 'mp':
"""no idea but the mp *nix runs are flaking out here often...
"""
pytest.skip("Test is too flaky on mp in CI")
timeout = 7 if platform.system() in ('Windows', 'Darwin') else 4
start = time.time()
results = trio.run(cancel_after, timeout, arb_addr)
diff = time.time() - start
assert results
return results, diff
def test_a_quadruple_example(time_quad_ex, ci_env, spawn_backend):
"""This also serves as a kind of "we'd like to be this fast test"."""
results, diff = time_quad_ex
assert results
this_fast = 6 if platform.system() in ('Windows', 'Darwin') else 3
assert diff < this_fast
@pytest.mark.parametrize(
'cancel_delay',
list(map(lambda i: i/10, range(3, 9)))
)
def test_not_fast_enough_quad(
arb_addr, time_quad_ex, cancel_delay, ci_env, spawn_backend
):
"""Verify we can cancel midway through the quad example and all actors
cancel gracefully.
"""
results, diff = time_quad_ex
delay = max(diff - cancel_delay, 0)
results = trio.run(cancel_after, delay, arb_addr)
system = platform.system()
if system in ('Windows', 'Darwin') and results is not None:
# In CI envoirments it seems later runs are quicker then the first
# so just ignore these
print(f"Woa there {system} caught your breath eh?")
else:
# should be cancelled mid-streaming
assert results is None
@tractor_test
async def test_respawn_consumer_task(
arb_addr,
spawn_backend,
loglevel,
):
"""Verify that ``._portal.ReceiveStream.shield()``
sucessfully protects the underlying IPC channel from being closed
when cancelling and respawning a consumer task.
This also serves to verify that all values from the stream can be
received despite the respawns.
"""
stream = None
async with tractor.open_nursery() as n:
portal = await n.start_actor(
name='streamer',
enable_modules=[__name__]
)
async with portal.open_stream_from(
stream_data,
seed=11,
) as stream:
expect = set(range(11))
received = []
# this is the re-spawn task routine
async def consume(task_status=trio.TASK_STATUS_IGNORED):
print('starting consume task..')
nonlocal stream
with trio.CancelScope() as cs:
task_status.started(cs)
# shield stream's underlying channel from cancellation
# with stream.shield():
async for v in stream:
print(f'from stream: {v}')
expect.remove(v)
received.append(v)
print('exited consume')
async with trio.open_nursery() as ln:
cs = await ln.start(consume)
while True:
await trio.sleep(0.1)
if received[-1] % 2 == 0:
print('cancelling consume task..')
cs.cancel()
# respawn
cs = await ln.start(consume)
if not expect:
print("all values streamed, BREAKING")
break
cs.cancel()
# TODO: this is justification for a
# ``ActorNursery.stream_from_actor()`` helper?
await portal.cancel_actor()