tractor/tests/test_cancellation.py

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"""
Cancellation and error propagation
"""
import platform
from itertools import repeat
import pytest
import trio
import tractor
from conftest import tractor_test
async def assert_err(delay=0):
await trio.sleep(delay)
assert 0
async def sleep_forever():
await trio.sleep(float('inf'))
async def do_nuthin():
# just nick the scheduler
await trio.sleep(0)
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@pytest.mark.parametrize(
'args_err',
[
# expected to be thrown in assert_err
({}, AssertionError),
# argument mismatch raised in _invoke()
({'unexpected': 10}, TypeError)
],
ids=['no_args', 'unexpected_args'],
)
def test_remote_error(arb_addr, args_err):
"""Verify an error raised in a subactor that is propagated
to the parent nursery, contains the underlying boxed builtin
error type info and causes cancellation and reraising all the
way up the stack.
"""
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args, errtype = args_err
async def main():
async with tractor.open_nursery() as nursery:
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portal = await nursery.run_in_actor('errorer', assert_err, **args)
# get result(s) from main task
try:
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await portal.result()
except tractor.RemoteActorError as err:
assert err.type == errtype
print("Look Maa that actor failed hard, hehh")
raise
with pytest.raises(tractor.RemoteActorError) as excinfo:
tractor.run(main, arbiter_addr=arb_addr)
# ensure boxed error is correct
assert excinfo.value.type == errtype
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def test_multierror(arb_addr):
"""Verify we raise a ``trio.MultiError`` out of a nursery where
more then one actor errors.
"""
async def main():
async with tractor.open_nursery() as nursery:
await nursery.run_in_actor('errorer1', assert_err)
portal2 = await nursery.run_in_actor('errorer2', assert_err)
# get result(s) from main task
try:
await portal2.result()
except tractor.RemoteActorError as err:
assert err.type == AssertionError
print("Look Maa that first actor failed hard, hehh")
raise
# here we should get a `trio.MultiError` containing exceptions
# from both subactors
with pytest.raises(trio.MultiError):
tractor.run(main, arbiter_addr=arb_addr)
@pytest.mark.parametrize('delay', (0, 0.5))
@pytest.mark.parametrize(
'num_subactors', range(25, 26),
)
def test_multierror_fast_nursery(arb_addr, start_method, num_subactors, delay):
"""Verify we raise a ``trio.MultiError`` out of a nursery where
more then one actor errors and also with a delay before failure
to test failure during an ongoing spawning.
"""
async def main():
async with tractor.open_nursery() as nursery:
for i in range(num_subactors):
await nursery.run_in_actor(
f'errorer{i}', assert_err, delay=delay)
with pytest.raises(trio.MultiError) as exc_info:
tractor.run(main, arbiter_addr=arb_addr)
assert exc_info.type == tractor.MultiError
err = exc_info.value
assert len(err.exceptions) == num_subactors
for exc in err.exceptions:
assert isinstance(exc, tractor.RemoteActorError)
assert exc.type == AssertionError
def do_nothing():
pass
def test_cancel_single_subactor(arb_addr):
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"""Ensure a ``ActorNursery.start_actor()`` spawned subactor
cancels when the nursery is cancelled.
"""
async def spawn_actor():
"""Spawn an actor that blocks indefinitely.
"""
async with tractor.open_nursery() as nursery:
portal = await nursery.start_actor(
'nothin', rpc_module_paths=[__name__],
)
assert (await portal.run(__name__, 'do_nothing')) is None
# would hang otherwise
await nursery.cancel()
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tractor.run(spawn_actor, arbiter_addr=arb_addr)
async def stream_forever():
for i in repeat("I can see these little future bubble things"):
# each yielded value is sent over the ``Channel`` to the
# parent actor
yield i
await trio.sleep(0.01)
@tractor_test
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async def test_cancel_infinite_streamer(start_method):
# stream for at most 1 seconds
with trio.move_on_after(1) as cancel_scope:
async with tractor.open_nursery() as n:
portal = await n.start_actor(
f'donny',
rpc_module_paths=[__name__],
)
# this async for loop streams values from the above
# async generator running in a separate process
async for letter in await portal.run(__name__, 'stream_forever'):
print(letter)
# we support trio's cancellation system
assert cancel_scope.cancelled_caught
assert n.cancelled
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@pytest.mark.parametrize(
'num_actors_and_errs',
[
# daemon actors sit idle while single task actors error out
(1, tractor.RemoteActorError, AssertionError, (assert_err, {}), None),
(2, tractor.MultiError, AssertionError, (assert_err, {}), None),
(3, tractor.MultiError, AssertionError, (assert_err, {}), None),
# 1 daemon actor errors out while single task actors sleep forever
(3, tractor.RemoteActorError, AssertionError, (sleep_forever, {}),
(assert_err, {}, True)),
# daemon actors error out after brief delay while single task
# actors complete quickly
(3, tractor.RemoteActorError, AssertionError,
(do_nuthin, {}), (assert_err, {'delay': 1}, True)),
# daemon complete quickly delay while single task
# actors error after brief delay
(3, tractor.MultiError, AssertionError,
(assert_err, {'delay': 1}), (do_nuthin, {}, False)),
],
ids=[
'1_run_in_actor_fails',
'2_run_in_actors_fail',
'3_run_in_actors_fail',
'1_daemon_actors_fail',
'1_daemon_actors_fail_all_run_in_actors_dun_quick',
'no_daemon_actors_fail_all_run_in_actors_sleep_then_fail',
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],
)
@tractor_test
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async def test_some_cancels_all(num_actors_and_errs, start_method, loglevel):
"""Verify a subset of failed subactors causes all others in
the nursery to be cancelled just like the strategy in trio.
This is the first and only supervisory strategy at the moment.
"""
num_actors, first_err, err_type, ria_func, da_func = num_actors_and_errs
try:
async with tractor.open_nursery() as n:
# spawn the same number of deamon actors which should be cancelled
dactor_portals = []
for i in range(num_actors):
dactor_portals.append(await n.start_actor(
f'deamon_{i}',
rpc_module_paths=[__name__],
))
func, kwargs = ria_func
riactor_portals = []
for i in range(num_actors):
# start actor(s) that will fail immediately
riactor_portals.append(
await n.run_in_actor(f'actor_{i}', func, **kwargs))
if da_func:
func, kwargs, expect_error = da_func
for portal in dactor_portals:
# if this function fails then we should error here
# and the nursery should teardown all other actors
try:
await portal.run(__name__, func.__name__, **kwargs)
except tractor.RemoteActorError as err:
assert err.type == err_type
# we only expect this first error to propogate
# (all other daemons are cancelled before they
# can be scheduled)
num_actors = 1
# reraise so nursery teardown is triggered
raise
else:
if expect_error:
pytest.fail(
"Deamon call should fail at checkpoint?")
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# should error here with a ``RemoteActorError`` or ``MultiError``
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except first_err as err:
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if isinstance(err, tractor.MultiError):
assert len(err.exceptions) == num_actors
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for exc in err.exceptions:
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if isinstance(exc, tractor.RemoteActorError):
assert exc.type == err_type
else:
assert isinstance(exc, trio.Cancelled)
elif isinstance(err, tractor.RemoteActorError):
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assert err.type == err_type
assert n.cancelled is True
assert not n._children
else:
pytest.fail("Should have gotten a remote assertion error?")
async def spawn_and_error(breadth, depth) -> None:
name = tractor.current_actor().name
async with tractor.open_nursery() as nursery:
for i in range(breadth):
if depth > 0:
args = (
f'spawner_{i}_depth_{depth}',
spawn_and_error,
)
kwargs = {
'breadth': breadth,
'depth': depth - 1,
}
else:
args = (
f'{name}_errorer_{i}',
assert_err,
)
kwargs = {}
await nursery.run_in_actor(*args, **kwargs)
@tractor_test
async def test_nested_multierrors(loglevel, start_method):
"""Test that failed actor sets are wrapped in `trio.MultiError`s.
This test goes only 2 nurseries deep but we should eventually have tests
for arbitrary n-depth actor trees.
"""
if start_method == 'trio_run_in_process':
depth = 3
subactor_breadth = 2
else:
# XXX: multiprocessing can't seem to handle any more then 2 depth
# process trees for whatever reason.
# Any more process levels then this and we see bugs that cause
# hangs and broken pipes all over the place...
if start_method == 'forkserver':
pytest.skip("Forksever sux hard at nested spawning...")
depth = 2
subactor_breadth = 2
with trio.fail_after(120):
try:
async with tractor.open_nursery() as nursery:
for i in range(subactor_breadth):
await nursery.run_in_actor(
f'spawner_{i}',
spawn_and_error,
breadth=subactor_breadth,
depth=depth,
)
except trio.MultiError as err:
assert len(err.exceptions) == subactor_breadth
for subexc in err.exceptions:
assert isinstance(subexc, tractor.RemoteActorError)
if depth > 1 and subactor_breadth > 1:
# XXX not sure what's up with this..
if platform.system() == 'Windows':
assert (subexc.type is trio.MultiError) or (
subexc.type is tractor.RemoteActorError)
else:
assert subexc.type is trio.MultiError
else:
assert (subexc.type is tractor.RemoteActorError) or (
subexc.type is trio.Cancelled)