In order to match a very significant and coming-soon patch set to the
IPC `Context` and `Channel` cancellation semantics with significant but
subtle changes to the primitives and runtime logic:
- a new set of `Context` state pub meth APIs for checking exact
inter-actor-linked-task outcomes such as `.outcome`, `.maybe_error`,
and `.cancel_acked`.
- trying to move away from `Context.cancelled_caught` usage since the
semantics from `trio` don't really map well (in terms of cancel
requests and how they result in cancel-scope graceful closure) and
`.cancel_acked: bool` is a better approach for IPC req-resp msging.
- change test usage to access `._scope.cancelled_caught` directly.
- more pedantic ctxc-raising expects around the "type of self
cancellation" and final outcome in ctxc cases:
- `ContextCancelled` is raised by ctx (`Context.result()`) consumer
methods when `Portal.cancel_actor()` is called (since it's an
out-of-band request) despite `Channel._cancel_called` being set.
- also raised by `.open_context().__aexit__()` on close.
- `.outcome` is always `.maybe_error` is always one of
`._local/remote_error`.
Currently if the spawn task is waiting on a daemon actor it is likely in
`await proc.wait()`, however, if the actor nursery is subsequently
cancelled this checkpoint will be abandoned and the hard proc reaping
sequence will execute which results in a up to 3 second wait before
a "hard" system signal is sent to the child. Ideally such
a cancelled-during-daemon-actor-wait condition is instead handled by
first trying to cancel the remote actor using `Portal.cancel_actor()` (a
"graceful" remote cancel request) which should (presuming normal runtime
operation) result in an immediate collection of the process after normal
actor (remotely triggered) runtime cancellation.
This resolves and completes #69 allowing all RPC invocation APIs to pass
function references directly instead of explicit `str` names for the
target namespace and function (this is still done implicitly
underneath). This brings us closer to `trio`'s task running API as well
as acknowledges that any inter-host RPC system (and API) will likely
need to be implemented on top of local RPC primitives anyway. Even if
this ends up **not** being true we can always go to "function stubs" as
part of our IAC protocol or, add a new method to do explicit namespace
calls: `.run_from_module()` or whatever everyone votes on.
Resolves#69
Further, this commit drops `Actor.statespace` from the entire system
since a user can easily get this same functionality using module
level variables. Fix docs to match all these changes (luckily mostly
already done due to example scripts referencing).
This appears to demonstrate the same bug found in #156. It looks like
cancelling a subactor with a child, while that child is running sync code,
can result in the child never getting cancelled due to some strange
condition where the internal nurseries aren't being torn down as
expected when a `trio.Cancelled` is raised.
- ease up on first stream test run deadline
- skip streaming tests in CI for mp backend, period
- give up on > 1 depth nested spawning with mp
- completely give up on slow spawning on windows
Verify ctrl-c, as a user would trigger it, properly cancels the actor
tree. This was an issue with `trio-run-in-process` that clearly wasn't
being handled correctly but for sure is now with the plain old
`trio` process spawner.
Resolves#115
Add a `--spawn-backend` option which can be set to one of {'mp',
'trio_run_in_process'} which will either run the test suite using the
`multiprocessing` or `trio-run-in-process` backend respectively.
Currently trying to run both in the same session can result in hangs
seemingly due to a lack of cleanup of forkservers / resource trackers
from `multiprocessing` which cause broken pipe errors on occasion (no
idea on the details).
For `test_cancellation.py::test_nested_multierrors`, use less nesting
when mp is used since it breaks if we push it too hard with the
whole recursive subprocess spawning thing...
It seems that mixing the two backends in the test suite results in hangs
due to lingering forkservers and resource managers from
`multiprocessing`? Likely we'll need either 2 separate CI runs to work
or someway to be sure that these lingering servers are killed in between
tests.
Another step toward having a complete test for #89.
Subactor breadth still seems to cause the most havoc and is why I've
kept that value to just 2 for now.
Add a test to verify that `trio.MultiError`s are properly propagated up
a simple actor nursery tree. We don't have any exception marshalling
between processes (yet) so we can't validate much more then a simple
2-depth tree. This satisfies the final bullet in #43.
Note I've limited the number of subactors per layer to around 5 since
any more then this seems to break the `multiprocessing` forkserver;
zombie subprocesses seem to be blocking teardown somehow...
Also add a single depth fast fail test just to verify that it's the
nested spawning that triggers this forkserver bug.
Tyler Goodlet
Tyler Goodlet