Add detailed ``@tractor.context`` cancellation/termination tests

transport_hardening
Tyler Goodlet 2021-06-13 20:25:36 -04:00
parent b63ccf0007
commit 11d471a4cd
1 changed files with 303 additions and 17 deletions

View File

@ -6,20 +6,13 @@ import pytest
import trio
import tractor
# from conftest import tractor_test
from conftest import tractor_test
# TODO: test endofchannel semantics / cancellation / error cases:
# 3 possible outcomes:
# - normal termination: far end relays a stop message with
# final value as in async gen from ``return <val>``.
# possible outcomes:
# - normal termination: far end returns
# - premature close: far end relays a stop message to tear down stream
# - cancel: far end raises `ContextCancelled`
# future possible outcomes
# - restart request: far end raises `ContextRestart`
# the general stream semantics are
# - normal termination: far end relays a stop message which
# terminates an ongoing ``MsgStream`` iteration
# - cancel termination: context is cancelled on either side cancelling
# the "linked" inter-actor task context
_state: bool = False
@ -30,6 +23,7 @@ async def simple_setup_teardown(
ctx: tractor.Context,
data: int,
block_forever: bool = False,
) -> None:
@ -41,8 +35,11 @@ async def simple_setup_teardown(
await ctx.started(data + 1)
try:
if block_forever:
# block until cancelled
await trio.sleep_forever()
else:
return 'yo'
finally:
_state = False
@ -56,7 +53,14 @@ async def assert_state(value: bool):
'error_parent',
[False, True],
)
def test_simple_context(error_parent):
@pytest.mark.parametrize(
'callee_blocks_forever',
[False, True],
)
def test_simple_context(
error_parent,
callee_blocks_forever,
):
async def main():
@ -70,11 +74,16 @@ def test_simple_context(error_parent):
async with portal.open_context(
simple_setup_teardown,
data=10,
block_forever=callee_blocks_forever,
) as (ctx, sent):
assert sent == 11
if callee_blocks_forever:
await portal.run(assert_state, value=True)
await ctx.cancel()
else:
assert await ctx.result() == 'yo'
# after cancellation
await portal.run(assert_state, value=False)
@ -94,6 +103,281 @@ def test_simple_context(error_parent):
trio.run(main)
# basic stream terminations:
# - callee context closes without using stream
# - caller context closes without using stream
# - caller context calls `Context.cancel()` while streaming
# is ongoing resulting in callee being cancelled
# - callee calls `Context.cancel()` while streaming and caller
# sees stream terminated in `RemoteActorError`
# TODO: future possible features
# - restart request: far end raises `ContextRestart`
@tractor.context
async def close_ctx_immediately(
ctx: tractor.Context,
) -> None:
await ctx.started()
global _state
async with ctx.open_stream():
pass
@tractor_test
async def test_callee_closes_ctx_after_stream_open():
'callee context closes without using stream'
async with tractor.open_nursery() as n:
portal = await n.start_actor(
'fast_stream_closer',
enable_modules=[__name__],
)
async with portal.open_context(
close_ctx_immediately,
# flag to avoid waiting the final result
# cancel_on_exit=True,
) as (ctx, sent):
assert sent is None
with trio.fail_after(0.5):
async with ctx.open_stream() as stream:
# should fall through since ``StopAsyncIteration``
# should be raised through translation of
# a ``trio.EndOfChannel`` by
# ``trio.abc.ReceiveChannel.__anext__()``
async for _ in stream:
assert 0
else:
# verify stream is now closed
try:
await stream.receive()
except trio.EndOfChannel:
pass
# TODO: should be just raise the closed resource err
# directly here to enforce not allowing a re-open
# of a stream to the context (at least until a time of
# if/when we decide that's a good idea?)
try:
async with ctx.open_stream() as stream:
pass
except trio.ClosedResourceError:
pass
await portal.cancel_actor()
@tractor.context
async def expect_cancelled(
ctx: tractor.Context,
) -> None:
global _state
_state = True
await ctx.started()
try:
async with ctx.open_stream() as stream:
async for msg in stream:
await stream.send(msg) # echo server
except trio.Cancelled:
# expected case
_state = False
raise
else:
assert 0, "Wasn't cancelled!?"
@pytest.mark.parametrize(
'use_ctx_cancel_method',
[False, True],
)
@tractor_test
async def test_caller_closes_ctx_after_callee_opens_stream(
use_ctx_cancel_method: bool,
):
'caller context closes without using stream'
async with tractor.open_nursery() as n:
portal = await n.start_actor(
'ctx_cancelled',
enable_modules=[__name__],
)
async with portal.open_context(
expect_cancelled,
) as (ctx, sent):
await portal.run(assert_state, value=True)
assert sent is None
# call cancel explicitly
if use_ctx_cancel_method:
await ctx.cancel()
try:
async with ctx.open_stream() as stream:
async for msg in stream:
pass
except tractor.ContextCancelled:
raise # XXX: must be propagated to __aexit__
else:
assert 0, "Should have context cancelled?"
# channel should still be up
assert portal.channel.connected()
# ctx is closed here
await portal.run(assert_state, value=False)
else:
try:
with trio.fail_after(0.2):
await ctx.result()
assert 0, "Callee should have blocked!?"
except trio.TooSlowError:
await ctx.cancel()
try:
async with ctx.open_stream() as stream:
async for msg in stream:
pass
except trio.ClosedResourceError:
pass
else:
assert 0, "Should have received closed resource error?"
# ctx is closed here
await portal.run(assert_state, value=False)
# channel should not have been destroyed yet, only the
# inter-actor-task context
assert portal.channel.connected()
# teardown the actor
await portal.cancel_actor()
@tractor_test
async def test_multitask_caller_cancels_from_nonroot_task():
async with tractor.open_nursery() as n:
portal = await n.start_actor(
'ctx_cancelled',
enable_modules=[__name__],
)
async with portal.open_context(
expect_cancelled,
) as (ctx, sent):
await portal.run(assert_state, value=True)
assert sent is None
async with ctx.open_stream() as stream:
async def send_msg_then_cancel():
await stream.send('yo')
await portal.run(assert_state, value=True)
await ctx.cancel()
await portal.run(assert_state, value=False)
async with trio.open_nursery() as n:
n.start_soon(send_msg_then_cancel)
try:
async for msg in stream:
assert msg == 'yo'
except tractor.ContextCancelled:
raise # XXX: must be propagated to __aexit__
# channel should still be up
assert portal.channel.connected()
# ctx is closed here
await portal.run(assert_state, value=False)
# channel should not have been destroyed yet, only the
# inter-actor-task context
assert portal.channel.connected()
# teardown the actor
await portal.cancel_actor()
@tractor.context
async def cancel_self(
ctx: tractor.Context,
) -> None:
global _state
_state = True
await ctx.cancel()
try:
with trio.fail_after(0.1):
await trio.sleep_forever()
except trio.Cancelled:
raise
except trio.TooSlowError:
# should never get here
assert 0
@tractor_test
async def test_callee_cancels_before_started():
'''callee calls `Context.cancel()` while streaming and caller
sees stream terminated in `ContextCancelled`.
'''
async with tractor.open_nursery() as n:
portal = await n.start_actor(
'cancels_self',
enable_modules=[__name__],
)
try:
async with portal.open_context(
cancel_self,
) as (ctx, sent):
async with ctx.open_stream():
await trio.sleep_forever()
# raises a special cancel signal
except tractor.ContextCancelled as ce:
ce.type == trio.Cancelled
# teardown the actor
await portal.cancel_actor()
@tractor.context
async def simple_rpc(
@ -207,6 +491,8 @@ def test_simple_rpc(server_func, use_async_for):
# stream should terminate here
# final context result(s) should be consumed here in __aexit__()
await portal.cancel_actor()
trio.run(main)