Mostly fixing edge cases with `asyncio` and/or bg threads where the
`.repl_release: trio.Event` needs to be used from the main `trio`
thread OW confusing-but-valid teardown tracebacks can show under various
races.
Also improve,
- log reporting for such internal bugs to make them more obvious on
console via `log.exception()`.
- only restore the SIGINT handler when runtime is (still) active.
- reporting when `tractor.pause(shield=True)` should be used and
unhiding the internal frames from the tb in that case.
- for `pause_from_sync()` some deep fixes..
|_add a `allow_no_runtime: bool = False` flag to allow
**not** requiring the actor runtime to be active.
|_fix the `greenback` case-branch to only trigger on `not
is_trio_thread`.
|_add a scope-global `repl_owner: Task|Thread|None = None` to
avoid ref errors..
Various `try`/`except` blocks around external APIs that raise when not
running inside an `tractor` and/or some async framework (mostly to avoid
too-late/benign error tbs on certain classes of actor tree teardown):
- for the `log.pdb()` prompts emitted before REPL console entry.
- inside `DebugStatus.is_main_trio_thread()`'s call to `sniffio`.
- in `_post_mortem()` by catching `NoRuntime` when called from a thread
still active after the `.open_root_actor()` has already exited.
Also,
- create a dedicated `DebugStateError` for raising instead of `assert`s
when we have actual debug-request inconsistencies (as seem to be most
likely with bg thread usage of `breakpoint()`).
- show the `open_crash_handler()` frame on `bdb.BdbQuit` (for now?)
Since it seems that `pdbp.xpm()` can sometimes lose the up-stack
traceback info/frames? Not sure why but ours seems to work just fine
from a `asyncio`-handler in `modden`'s use of `i3ipc` B)
Also call `DebugStatus.shield_sigint()` from `pause_from_sync()` in the
infected-`asyncio` case to get the same shielding behaviour as in all
other usage!
Mostly due to magic from @oremanj where we slap in a little bit of
`.from_asyncio`-type stuff to run a `trio`-task from `asyncio.Task`
code!
I'm not gonna go into tooo too much detail but basically the primary
thing needed was a way to (blocking-ly) invoke a `trio.lowlevel.Task`
from an `asyncio` one (which we now have with a new
`run_trio_task_in_future()` thanks to draft code from the aforementioned
jefe) which we now invoke from a dedicated aio case-branch inside
`.devx._debug.pause_from_sync()`. Further include a case inside
`DebugStatus.release()` to handle using the same func to set the
`repl_release: trio.Event` from the aio side when releasing the REPL on
exit cmds.
Prolly more refinements to come ;{o
The final issue was making sure we do the same thing on ctl-c/SIGINT
from the user. That is, if there's already a bg-thread in REPL, we
`log.pdb()` about SIGINT shielding and re-draw the prompt; the same UX
as normal actor-runtime-task behaviour.
Reasons this wasn't workin.. and the fix:
- `.pause_from_sync()` was overriding the local `repl` var with `None`
delivered by (transitive) calls to `_pause(debug_func=None)`.. so
remove all that and only assign it OAOO prior to thread-type case
branching.
- always call `DebugStatus.shield_sigint()` as needed from all requesting
threads/tasks:
- in `_pause_from_bg_root_thread()` BEFORE calling `._pause()` AND BEFORE
yielding back to the bg-thread via `.started(out)` to ensure we're
definitely overriding the handler in the `trio`-main-thread task
before unblocking the requesting bg-thread.
- from any requesting bg-thread in the root actor such that both its
main-`trio`-thread scheduled task (as per above bullet) AND it are
SIGINT shielded.
- always call `.shield_sigint()` BEFORE any `greenback._await()` case
don't entirely grok why yet, but it works)?
- for `greenback._await()` case always set `bg_task` to the current one..
- tweaks to the `SIGINT` handler, now renamed `sigint_shield()` so as
not to name-collide with the methods when editor-searching:
- always try to `repr()` the REPL thread/task "owner" as well as the
active `PdbREPL` instance.
- add `.devx()` notes around the prompt flushing deats and comments
for any root-actor-bg-thread edge cases.
Related/supporting refinements:
- add `get_lock()`/`get_debug_req()` factory funcs since the plan is to
eventually implement both as `@singleton` instances per actor.
- fix `acquire_debug_lock()`'s call-sig-bug for scheduling
`request_root_stdio_lock()`..
- in `._pause()` only call `mk_pdb()` when `debug_func != None`.
- add some todo/warning notes around the `cls.repl = None` in
`DebugStatus.release()`
`test_pause_from_sync()` tweaks:
- don't use a `attach_patts.copy()`, since we always `break` on match.
- do `pytest.fail()` on that ^ loop's fallthrough..
- pass `do_ctlc(child, patt=attach_key)` such that we always match the
the current thread's name with the ctl-c triggered `.pdb()` emission.
- oh yeah, return the last `before: str` from `do_ctlc()`.
- in the script, flip `abandon_on_cancel=True` since when `False` it
seems to cause `trio.run()` to hang on exit from the last bg-thread
case?!?
In `lock_stdio_for_peer()` better internal-error handling/reporting:
- only `Lock._blocked.remove(ctx.cid)` if that same cid was added on
entry to avoid needless key-errors.
- drop all `Lock.release(force: bool)` usage remnants.
- if `req_ctx.cancel()` fails mention it with `ctx_err.add_note()`.
- add more explicit internal-failed-request log messaging via a new
`fail_reason: str`.
- use and use new `x)<=\n|_` annots in any failure logging.
Other cleanups/niceties:
- drop `force: bool` flag entirely from the `Lock.release()`.
- use more supervisor-op-annots in `.pdb()` logging
with both `_pause/crash_msg: str` instead of double '|' lines when
`.pdb()`-reported from `._set_trace()`/`._post_mortem()`.
Since we more or less require it for `tractor.pause_from_sync()` this
refines enable toggles and their relay down the actor tree as well as
more explicit logging around init and activation.
Tweaks summary:
- `.info()` report the module if discovered during root boot.
- use a `._state._runtime_vars['use_greenback']: bool` activation flag
inside `Actor._from_parent()` to determine if the sub should try to
use it and set to `False` if mod-loading fails / not installed.
- expose `maybe_init_greenback()` from `.devx` sugpkg.
- comment out RTE in `._pause()` for now since we already have it in
`.pause_from_sync()`.
- always `.exception()` on `maybe_init_greenback()` import errors to
clarify the underlying failure deats.
- always explicitly report if `._state._runtime_vars['use_greenback']`
was NOT set when `.pause_from_sync()` is called.
Other `._runtime.async_main()` adjustments:
- combine the "internal error call ur parents" message and the failed
registry contact status into one new `err_report: str`.
- drop the final exception handler's call to
`Actor.lifetime_stack.close()` since we're already doing it in the
`finally:` block and the earlier call has no currently known benefit.
- only report on the `.lifetime_stack()` callbacks if any are detected
as registered.
Namely passing the `.__pld_spec__` directly to the
`lock_stdio_for_peer()` decorator B)
Also, allows dropping `apply_debug_pldec()` (which was a todo) and
removing a `lock_stdio_for_peer()` indent level.
Hopefully would make grok-ing this fairly sophisticated sub-sys possible
for any up-and-coming `tractor` hacker
XD
A lot of internal API and re-org ideas I discovered/realized as part of
finishing the `__pld_spec__` and multi-threaded support. Particularly
better isolation between root-actor vs subactor task APIs and generally
less globally-state-ful stuff like `DebugStatus` and `Lock` method APIs
would likely make a lot of the hard to follow edge cases more clear?
Functionally working for multi-threaded (via cpython threads spawned
from `to_trio.to_thread.run_sync()`) alongside subactors, tested (for
now) only with threads started inside the root actor (which seemed to
have the most issues in terms of the impl and special cases..) using the
new `tractor.pause_from_sync()` API!
Main implementation changes to `.pause_from_sync()`
------ - ------
- from the root actor, we need to ensure bg thread case is handled
*specially* since no IPC is used to request the TTY stdio mutex and
`Lock` (API) usage is conducted entirely from a local task or thread;
dedicated `Lock` usage for the root-actor already is branched inside
`._pause()` and needs similar handling from a root bg-thread:
|_for the special case of a root bg thread we need to
`trio`-main-thread schedule a bg task inside a new
`_pause_from_bg_root_thread()`. The new task needs to implement most
of what was is handled inside `._pause()` manually, mostly because in
this root-actor-bg-thread case we have 2 constraints:
1. to enter `PdbREPL.interaction()` **from the bg thread** directly,
2. the task that `Lock._debug_lock.acquire()`s has to be the same
that calls `.release() (a `trio.FIFOLock` constraint)
|_impl deats of this `_pause_from_bg_root_thread()` include:
- (for now) calling `._pause()` to acquire the `Lock._debug_lock`.
- setting its own `DebugStatus.repl_release`.
- calling `.DebugStatus.shield_sigint()` to ensure the root's
main thread uses the right handler when the bg one is REPL-ing.
- wait manually on the `.repl_release()` to be set by the thread's
dedicated `PdbREPL` exit.
- manually calling `Lock.release()` from the **same task** that
acquired it.
- expect calls to `._pause()` to deliver a `tuple[Task, PdbREPL]` such
that we always get the handle both to any newly created REPl instance
and the (maybe) the scheduled bg task within which is runs.
- add a single `message: str` style to `log.devx()` based on branching
style for logging.
- ensure both `DebugStatus.repl` and `.repl_task` are set **just
before** calling `._set_trace()` to ensure the correct `Task|Thread`
is set when the REPL is finally entered from sync code.
- add a wrapping caller `_sync_pause_from_builtin()` which passes in the
new `called_from_builtin=True` to indicate `breakpoint()` caller
usage, obvi pass in `api_frame`.
Changes to `._pause()` in support of ^
------ - ------
- `TaskStatus.started()` and return the `tuple[Task, PdbREPL]` to
callers / starters.
- only call `DebugStatus.shield_sigint()` when no `repl` passed bc some
callers (like bg threads) may need to apply it at some specific point
themselves.
- tweak some asserts for the `debug_func == None` / non-`trio`-thread
case.
- add a mod-level `_repl_fail_msg: str` to be used when there's an
internal `._pause()` failure for testing, easier to pexpect match.
- more comprehensive logging for the root-actor branched case to
(attempt to) indicate any of the 3 cases:
- remote ctx from subactor has the `Lock`,
- already existing root task or thread has it or,
- some kinda stale `.locked()` situation where the root has the lock
but we don't know why.
- for root usage, revert to always `await Lock._debug_lock.acquire()`-ing
despite `called_from_sync` since `.pause_from_sync()` was reworked to
instead handle the special bg thread case in the new
`_pause_from_bg_root_thread()` task.
- always do `return _enter_repl_sync(debug_func)`.
- try to report any `repl_task: Task|Thread` set by the caller
(particularly for the bg thread cases) as being the thread or task
`._pause()` was called "on behalf of"
Changes to `DebugStatus`/`Lock` in support of ^
------ - ------
- only call `Lock.release()` from `DebugStatus.set_[quit/continue]()`
when called from the main `trio` thread and always call
`DebugStatus.release()` **after** to ensure `.repl_released()` is set
**after** `._debug_lock.release()`.
- only call `.repl_release.set()` from `trio` thread otherwise use
`.from_thread.run()`.
- much more refinements in `Lock.release()` for threading cases:
- return `bool` to indicate whether lock was released by caller.
- mask (in prep to drop) `_pause()` usage of
`Lock.release.force=True)` since forcing a release can't ever avoid
the RTE from `trio`.. same task **must** acquire/release.
- don't allow usage from non-`trio`-main-threads, ever; there's no
point since the same-task-needs-to-manage-`FIFOLock` constraint.
- much more detailed logging using `message`-building-style for all
caller (edge) cases.
|_ use a `we_released: bool` to determine failed-to-release edge
cases which can happen if called from bg threads, ensure we
`log.exception()` on any incorrect usage resulting in release
failure.
|_ complain loudly if the release fails and some other task/thread
still holds the lock.
|_ be explicit about "who" (which task or thread) the release is "on
behalf of" by reading `DebugStatus.repl_task` since the caller
isn't the REPL operator in many sync cases.
- more or less drop `force` support, as mentioned above.
- ensure we unset `._owned_by_root` if the caller is a root task.
Other misc
------ - ------
- rename `lock_tty_for_child()` -> `lock_stdio_for_peer()`.
- rejig `Lock.repr()` to show lock and event stats.
- stage `Lock.stats` and `.owner` methods in prep for doing a singleton
instance and `@property`s.
Originally discovered as while using `tractor.pause_from_sync()`
from the `i3ipc` client running in a bg-thread that uses `asyncio`
inside `modden`.
Turns out we definitely aren't correctly handling `.pause_from_sync()`
from the root actor when called from a `trio.to_thread.run_sync()`
bg thread:
- root-actor bg threads which can't `Lock._debug_lock.acquire()` since
they aren't in `trio.Task`s.
- even if scheduled via `.to_thread.run_sync(_debug._pause)` the
acquirer won't be the task/thread which calls `Lock.release()` from
`PdbREPL` hooks; this results in a RTE raised by `trio`..
- multiple threads will step on each other's stdio since cpython's GIL
seems to ctx switch threads on every input from the user to the REPL
loop..
Reproduce via reworking our example and test so that they catch and fail
for all edge cases:
- rework the `/examples/debugging/sync_bp.py` example to demonstrate the
above issues, namely the stdio clobbering in the REPL when multiple
threads and/or a subactor try to debug simultaneously.
|_ run one thread using a task nursery to ensure it runs conc with the
nursery's parent task.
|_ ensure the bg threads run conc a subactor usage of
`.pause_from_sync()`.
|_ gravely detail all the special cases inside a TODO comment.
|_ add some control flags to `sync_pause()` helper and don't use
`breakpoint()` by default.
- extend and adjust `test_debugger.test_pause_from_sync` to match (and
thus currently fail) by ensuring exclusive `PdbREPL` attachment when
the 2 bg root-actor threads are concurrently interacting alongside the
subactor:
|_ should only see one of the `_pause_msg` logs at a time for either
one of the threads or the subactor.
|_ ensure each attaches (in no particular order) before expecting the
script to exit.
Impl adjustments to `.devx._debug`:
- drop `Lock.repl`, no longer used.
- add `Lock._owned_by_root: bool` for the `.ctx_in_debug == None`
root-actor-task active case.
- always `log.exception()` for any `._debug_lock.release()` ownership
RTE emitted by `trio`, like we used to..
- add special `Lock.release()` log message for the stale lock but
`._owned_by_root == True` case; oh yeah and actually
`log.devx(message)`..
- rename `Lock.acquire()` -> `.acquire_for_ctx()` since it's only ever
used from subactor IPC usage; well that and for local root-task
usage we should prolly add a `.acquire_from_root_task()`?
- buncha `._pause()` impl improvements:
|_ type `._pause()`'s `debug_func` as a `partial` as well.
|_ offer `called_from_sync: bool` and `called_from_bg_thread: bool`
for the special case handling when called from `.pause_from_sync()`
|_ only set `DebugStatus.repl/repl_task` when `debug_func != None`
(OW ensure the `.repl_task` is not the current one).
|_ handle error logging even when `debug_func is None`..
|_ lotsa detailed commentary around root-actor-bg-thread special cases.
- when `._set_trace(hide_tb=False)` do `pdbp.set_trace(frame=currentframe())`
so the `._debug` internal frames are always included.
- by default always hide tracebacks for `.pause[_from_sync]()` internals.
- improve `.pause_from_sync()` to avoid root-bg-thread crashes:
|_ pass new `called_from_xxx_` flags and ensure `DebugStatus.repl_task`
is actually set to the `threading.current_thread()` when needed.
|_ manually call `Lock._debug_lock.acquire_nowait()` for the non-bg
thread case.
|_ TODO: still need to implement the bg-thread case using a bg
`trio.Task`-in-thread with an `trio.Event` set by thread REPL exit.
It's been a long time prepped and now finally implemented!
Offer a `shield: bool` argument from our async `._debug` APIs:
- `await tractor.pause(shield=True)`,
- `await tractor.post_mortem(shield=True)`
^-These-^ can now be used inside cancelled `trio.CancelScope`s,
something very handy when introspecting complex (distributed) system
tear/shut-downs particularly under remote error or (inter-peer)
cancellation conditions B)
Thanks to previous prepping in a prior attempt and various patches from
the rigorous rework of `.devx._debug` internals around typed msg specs,
there ain't much that was needed!
Impl deats
- obvi passthrough `shield` from the public API endpoints (was already
done from a prior attempt).
- put ad-hoc internal `with trio.CancelScope(shield=shield):` around all
checkpoints inside `._pause()` for both the root-process and subactor
case branches.
Add a fairly rigorous example, `examples/debugging/shielded_pause.py`
with a wrapping `pexpect` test, `test_debugger.test_shield_pause()` and
ensure it covers as many cases as i can think of offhand:
- multiple `.pause()` entries in a loop despite parent scope
cancellation in a subactor RPC task which itself spawns a sub-task.
- a `trio.Nursery.parent_task` which raises, is handled and
tries to enter and unshielded `.post_mortem()`, which of course
internally raises `Cancelled` in a `._pause()` checkpoint, so we catch
the `Cancelled` again and then debug the debugger's internal
cancellation with specific checks for the particular raising
checkpoint-LOC.
- do ^- the latter -^ for both subactor and root cases to ensure we
can debug `._pause()` itself when it tries to REPL engage from
a cancelled task scope Bo
Call it `hide_runtime_frames()` and stick all the lines from the top of
the `._debug` mod in there along with a little `log.devx()` emission on
what gets hidden by default ;)
Other,
- fix ref-error where internal-error handler might trigger despite the
debug `req_ctx` not yet having init-ed, such that we don't try to
cancel or log about it when it never was fully created/initialize..
- fix assignment typo iniside `_set_trace()` for `task`.. lel
More or less by pedantically separating and managing root and subactor
request syncing events to always be managed by the locking IPC context
task-funcs:
- for the root's "child"-side, `lock_tty_for_child()` directly creates
and sets a new `Lock.req_handler_finished` inside a `finally:`
- for the sub's "parent"-side, `request_root_stdio_lock()` does the same
with a new `DebugStatus.req_finished` event and separates it from
the `.repl_release` event (which indicates a "c" or "q" from user and
thus exit of the REPL session) as well as sets a new `.req_task:
trio.Task` to explicitly distinguish from the app-user-task that
enters the REPL vs. the paired bg task used to request the global
root's stdio mutex alongside it.
- apply the `__pld_spec__` on "child"-side of the ctx using the new
`Portal.open_context(pld_spec)` parameter support; drops use of any
`ContextVar` malarky used prior for `PldRx` mgmt.
- removing `Lock.no_remote_has_tty` since it was a nebulous name and
from the prior "everything is in a `Lock`" design..
------ - ------
More rigorous impl to handle various edge cases in `._pause()`:
- rejig `_enter_repl_sync()` to wrap the `debug_func == None` case
inside maybe-internal-error handler blocks.
- better logic for recurrent vs. multi-task contention for REPL entry in
subactors, by guarding using `DebugStatus.req_task` and by now waiting
on the new `DebugStatus.req_finished` for the multi-task contention
case.
- even better internal error handling and reporting for when this code
is hacked on and possibly broken ;p
------ - ------
Updates to `.pause_from_sync()` support:
- add optional `actor`, `task` kwargs to `_set_trace()` to allow
compat with the new explicit `debug_func` calling in `._pause()` and
pass a `threading.Thread` for `task` in the `.to_thread()` usage case.
- add an `except` block that tries to show the frame on any internal
error.
------ - ------
Relatedly includes a buncha cleanups/simplifications somewhat in
prep for some coming refinements (around `DebugStatus`):
- use all the new attrs mentioned above as needed in the SIGINT shielder.
- wait on `Lock.req_handler_finished` in `maybe_wait_for_debugger()`.
- dropping a ton of masked legacy code left in during the recent reworks.
- better comments, like on the use of `Context._scope` for shielding on
the "child"-side to avoid the need to manage yet another cs.
- add/change-to lotsa `log.devx()` level emissions for those infos which
are handy while hacking on the debugger but not ideal/necessary to be
user visible.
- obvi add lotsa follow up todo notes!
Finally got this working so that if/when an internal bug is introduced
to this request task-func, we can actually REPL-debug the lock request
task itself B)
As in, if the subactor's lock request task internally errors we,
- ensure the task always terminates (by calling `DebugStatus.release()`)
and explicitly reports (via a `log.exception()`) the internal error.
- capture the error instance and set as a new `DebugStatus.req_err` and
always check for it on final teardown - in which case we also,
- ensure it's reraised from a new `DebugRequestError`.
- unhide the stack frames for `_pause()`, `_enter_repl_sync()` so that
the dev can upward inspect the `_pause()` call stack sanely.
Supporting internal impl changes,
- add `DebugStatus.cancel()` and `.req_err`.
- don't ever cancel the request task from
`PdbREPL.set_[continue/quit]()` only when there's some internal error
that would likely result in a hang and stale lock state with the root.
- only release the root's lock when the current ask is also the owner
(avoids bad release errors).
- also show internal `._pause()`-related frames on any `repl_err`.
Other temp-dev-tweaks,
- make pld-dec change log msgs info level again while solving this
final context-vars race stuff..
- drop the debug pld-dec instance match asserts for now since
the problem is already caught (and now debug-able B) by an attr-error
on the decoded-as-`dict` started msg, and instead add in
a `log.exception()` trace to see which task is triggering the case
where the debug `MsgDec` isn't set correctly vs. when we think it's
being applied.
Since obviously the thread is likely expected to halt and raise after
the REPL session exits; this was a regression from the prior impl. The
main reason for this is that otherwise the request task will never
unblock if the user steps through the crashed task using 'next' since
the `.do_next()` handler doesn't by default release the request since in
the `.pause()` case this would end the session too early.
Other,
- toss in draft `Pdb.user_exception()`, though doesn't seem to ever
trigger?
- only release `Lock._debug_lock` when already locked.
Since i was running into them (internal errors) during lock request
machinery dev and was getting all sorts of difficult to understand hangs
whenever i intro-ed a bug to either side of the ipc ctx; this all while
trying to get the msg-spec working for `Lock` requesting subactors..
Deats:
- hideframes for `@acm`s and `trio.Event.wait()`, `Lock.release()`.
- better detail out the `Lock.acquire/release()` impls
- drop `Lock.remote_task_in_debug`, use new `.ctx_in_debug`.
- add a `Lock.release(force: bool)`.
- move most of what was `_acquire_debug_lock_from_root_task()` and some
of the `lock_tty_for_child().__a[enter/exit]()` logic into
`Lock.[acquire/release]()` including bunch more logging.
- move `lock_tty_for_child()` up in the module to below `Lock`, with
some rework:
- drop `subactor_uid: tuple` arg since we can just use the `ctx`..
- add exception handler blocks for reporting internal (impl) errors
and always force release the lock in such cases.
- extend `DebugStatus` (prolly will rename to `DebugRequest` btw):
- add `.req_ctx: Context` for subactor side.
- add `.req_finished: trio.Event` to sub to signal request task exit.
- extend `.shield_sigint()` doc-str.
- add `.release()` to encaps all the state mgmt previously strewn
about inside `._pause()`..
- use new `DebugStatus.release()` to replace all the duplication:
- inside `PdbREPL.set_[continue/quit]()`.
- inside `._pause()` for the subactor branch on internal
repl-invocation error cases,
- in the `_enter_repl_sync()` closure on error,
- replace `apply_debug_codec()` -> `apply_debug_pldec()` in tandem with
the new `PldRx` sub-sys which handles the new `__pld_spec__`.
- add a new `pformat_cs()` helper orig to help debug cs stack
a corruption; going to move to `.devx.pformat` obvi.
- rename `wait_for_parent_stdin_hijack()` -> `request_root_stdio_lock()`
with improvements:
- better doc-str and add todos,
- use `DebugStatus` more stringently to encaps all subactor req state.
- error handling blocks for cancellation and straight up impl errors
directly around the `.open_context()` block with the latter doing
a `ctx.cancel()` to avoid hanging in the shielded `.req_cs` scope.
- similar exc blocks for the func's overall body with explicit
`log.exception()` reporting.
- only set the new `DebugStatus.req_finished: trio.Event` in `finally`.
- rename `mk_mpdb()` -> `mk_pdb()` and don't cal `.shield_sigint()`
implicitly since the caller usage does matter for this.
- factor out `any_connected_locker_child()` from the SIGINT handler.
- rework SIGINT handler to better handle any stale-lock/hang cases:
- use new `Lock.ctx_in_debug: Context` to detect subactor-in-debug.
and use it to cancel any lock request instead of the lower level
- use `problem: str` summary approach to log emissions.
- rework `_pause()` given all of the above, stuff not yet mentioned:
- don't take `shield: bool` input and proxy to `debug_func()` (for now).
- drop `extra_frames_up_when_async: int` usage, expect
`**debug_func_kwargs` to passthrough an `api_frame: Frametype` (more
on this later).
- lotsa asserts around the request ctx vs. task-in-debug ctx using new
`current_ipc_ctx()`.
- asserts around `DebugStatus` state.
- rework and simplify the `debug_func` hooks,
`_set_trace()`/`_post_mortem()`:
- make them accept a non-optional `repl: PdbRepl` and `api_frame:
FrameType` which should be used to set the current frame when the
REPL engages.
- always hide the hook frames.
- always accept a `tb: TracebackType` to `_post_mortem()`.
|_ copy and re-impl what was the delegation to
`pdbp.xpm()`/`pdbp.post_mortem()` and instead call the
underlying `Pdb.interaction()` ourselves with a `caller_frame`
and tb instance.
- adjust the public `.pause()` impl:
- accept optional `hide_tb` and `api_frame` inputs.
- mask opening a cancel-scope for now (can cause `trio` stack
corruption, see notes) and thus don't use the `shield` input other
then to eventually passthrough to `_post_mortem()`?
|_ thus drop `task_status` support for now as well.
|_ pretty sure correct soln is a debug-nursery around `._invoke()`.
- since no longer using `extra_frames_up_when_async` inside
`debug_func()`s ensure all public apis pass a `api_frame`.
- re-impl our `tractor.post_mortem()` to directly call into `._pause()`
instead of binding in via `partial` and mk it take similar input as
`.pause()`.
- drop `Lock.release()` from `_maybe_enter_pm()`, expose and pass
expected frame and tb.
- use necessary changes from all the above within
`maybe_wait_for_debugger()` and `acquire_debug_lock()`.
Lel, sorry thought that would be shorter..
There's still a lot more re-org to do particularly with `DebugStatus`
encapsulation but it's coming in follow up.
Breaks out all the (sub)actor local conc primitives from `Lock` (which
is now only used in and by the root actor) such that there's an explicit
distinction between a task that's "consuming" the `Lock` (remotely) vs.
the root-side service tasks which do the actual acquire on behalf of the
requesters.
`DebugStatus` changeover deats:
------ - ------
- move all the actor-local vars over `DebugStatus` including:
- move `_trio_handler` and `_orig_sigint_handler`
- `local_task_in_debug` now `repl_task`
- `_debugger_request_cs` now `req_cs`
- `local_pdb_complete` now `repl_release`
- drop all ^ fields from `Lock.repr()` obvi..
- move over the `.[un]shield_sigint()` and
`.is_main_trio_thread()` methods.
- add some new attrs/meths:
- `DebugStatus.repl` for the currently running `Pdb` in-actor
singleton.
- `.repr()` for pprint of state (like `Lock`).
- Note: that even when a root-actor task is in REPL, the `DebugStatus`
is still used for certain actor-local state mgmt, such as SIGINT
handler shielding.
- obvi change all lock-requester code bits to now use a `DebugStatus` in
their local actor-state instead of `Lock`, i.e. change usage from
`Lock` in `._runtime` and `._root`.
- use new `Lock.get_locking_task_cs()` API in when checking for
sub-in-debug from `._runtime.Actor._stream_handler()`.
Unrelated to topic-at-hand tweaks:
------ - ------
- drop the commented bits about hiding `@[a]cm` stack frames from
`_debug.pause()` and simplify to only one block with the `shield`
passthrough since we already solved the issue with cancel-scopes using
`@pdbp.hideframe` B)
- this includes all the extra logging about the extra frame for the
user (good thing i put in that wasted effort back then eh..)
- put the `try/except BaseException` with `log.exception()` around the
whole of `._pause()` to ensure we don't miss in-func errors which can
cause hangs..
- allow passing in `portal: Portal` to
`Actor.start_remote_task()` such that `Portal` task spawning methods
are always denoted correctly in terms of `Context.side`.
- lotsa logging tweaks, decreasing a bit of noise from `.runtime()`s.
Since it's totes possible to have a spec applied that won't permit
`str`s, might as well formalize a small msg set for subactors to request
the tree-wide TTY `Lock`.
BTW, I'm prolly not going into every single change here in this first
WIP since there's still a variety of broken stuff mostly to do with
races on the codec apply being done in a `trio.lowleve.RunVar`; it
should be re-done with a `ContextVar` such that each task does NOT
mutate the global setting..
New msg set and usage is simply:
- `LockStatus` which is the reponse msg delivered from `lock_tty_for_child()`
- `LockRelease` a one-off request msg from the subactor to drop the
`Lock` from a `MsgStream.send()`.
- use these msgs throughout the root and sub sides of the locking
ctx funcs: `lock_tty_for_child()` & `wait_for_parent_stdin_hijack()`
The codec is now applied in both the root and sub `Lock` request tasks:
- for root inside `lock_tty_for_child()` before the `.started()`.
- for subs, inside `wait_for_parent_stdin_hijack()` since we only want
to affect the codec *for the locking task*.
- (hence the need for ctx-var as mentioned above but currently this
can cause races which will break against other app tasks competing
for the codec setting).
- add a `apply_debug_codec()` helper for use in both cases.
- add more detailed logging to both the root and sub side of `Lock`
requesting funcs including requiring that the sub-side task "uid" (a
`tuple[str, int]` = (trio.Task.name, id(trio.Task)` be provided (more
on this later).
A main issue discovered while proto-testing all this was the ability of
a sub to "double lock" (leading to self-deadlock) via an error in
`wait_for_parent_stdin_hijack()` which, for ex., can happen in debug
mode via crash handling of a `MsgTypeError` received from the root
during a codec applied msg-spec race! Originally I was attempting to
solve this by making the SIGINT override handler more resilient but this
case is somewhat impossible to detect by an external root task other
then checking for duplicate ownership via the new `subactor_task_uid`.
=> SO NOW, we always stick the current task uid in the
`Lock._blocked: set` and raise an rte on a double request by the same
remote task.
Included is a variety of small refinements:
- finally figured out how to mark a variety of `.__exit__()` frames with
`pdbp.hideframe()` to actually hide them B)
- add cls methods around managing `Lock._locking_task_cs` from root only.
- re-org all the `Lock` attrs into those only used in root vs. subactors
and proto-prep a new `DebugStatus` actor-singleton to be used in subs.
- add a `Lock.repr()` to contextually print the current conc primitives.
- rename our `Pdb`-subtype to `PdbREPL`.
- rigor out the SIGINT handler a bit, originally to try and hack-solve
the double-lock issue mentioned above, but now just with better
logging and logic for most (all?) possible hang cases that should be
hang-recoverable after enough ctrl-c mashing by the user.. well
hopefully:
- using `Lock.repr()` for both root and sub cases.
- lots more `log.warn()`s and handler reversions on stale lock or cs
detection.
- factor `._pause()` impl a little better moving the actual repl entry
to a new `_enter_repl_sync()` (originally for easier wrapping in the
sub case with `apply_codec()`).
Only warn log on a non-`trio` async lib when in the main thread to
avoid a name error when in the non-`asyncio` non-main-thread case.
=> To cherry into the `.pause_from_sync()` feature branch.
It's **almost** there, we're just missing the final translation code to
get from an `asyncio` side task to be able to call
`.devx._debug..wait_for_parent_stdin_hijack()` to do root actor TTY
locking. Then we just need to ensure internals also do the right thing
with `greenback()` for equivalent sync `breakpoint()` style pause
points.
Since i'm deferring this until later, tossing in some xfail tests to
`test_infected_asyncio` with TODOs for the needed implementation as well
as eventual test org.
By "provision" it means we add:
- `greenback` init block to `_run_asyncio_task()` when debug mode is
enabled (but which will currently rte when `asyncio` is detected)
using `.bestow_portal()` around the `asyncio.Task`.
- a call to `_debug.maybe_init_greenback()` in the `run_as_asyncio_guest()`
guest-mode entry point.
- as part of `._debug.Lock.is_main_trio_thread()` whenever the async-lib
is not 'trio' error lock the backend name (which is obvi `'asyncio'`
in this use case).
Change the name to `Lock.is_main_trio_thread()` indicating that when
`True` the thread is both the main one **and** the one that called
`trio.run()`. Add a todo for just copying the
`trio._util.is_main_thread()` impl (since it's private / may change) and
some brief notes about potential usage of
`trio.from_thread.check_cancelled()` to detect non-`.to_thread` thread
spawns.
Now supports use from any `trio` task, any sync thread started with
`trio.to_thread.run_sync()` AND also via `breakpoint()` builtin API!
The only bit missing now is support for `asyncio` tasks when in infected
mode.. Bo
`greenback` setup/API adjustments:
- move `._rpc.maybe_import_gb()` to -> `devx._debug` and factor out the cached
import checking into a sync func whilst placing the async `.ensure_portal()`
bootstrapping into a new async `maybe_init_greenback()`.
- use the new init-er func inside `open_root_actor()` with the output
predicating whether we override the `breakpoint()` hook.
core `devx._debug` implementation deatz:
- make `mk_mpdb()` only return the `pdp.Pdb` subtype instance since
the sigint unshielding func is now accessible from the `Lock`
singleton from anywhere.
- add non-main thread support (at least for `trio.to_thread` use cases)
to our `Lock` with a new `.is_trio_thread()` predicate that delegates
directly to `trio`'s internal version.
- do `Lock.is_trio_thread()` checks inside any methods which require
special provisions when invoked from a non-main `trio` thread:
- `.[un]shield_sigint()` methods since `signal.signal` usage is only
allowed from cpython's main thread.
- `.release()` since `trio.StrictFIFOLock` can only be called from
a `trio` task.
- rework `.pause_from_sync()` itself to directly call `._set_trace()`
and don't bother with `greenback._await()` when we're already calling
it from a `.to_thread.run_sync()` thread, oh and try to use the
thread/task name when setting `Lock.local_task_in_debug`.
- make it an RTE for now if you try to use `.pause_from_sync()` from any
infected-`asyncio` task, but support is (hopefully) coming soon!
For testing we add a new `test_debugger.py::test_pause_from_sync()`
which includes a ctrl-c parametrization around the
`examples/debugging/sync_bp.py` script which includes all currently
supported/working usages:
- `tractor.pause_from_sync()`.
- via `breakpoint()` overload.
- from a `trio.to_thread.run_sync()` spawn.
We're passing a `extra_frames_up_when_async=2` now (from prior attempt
to hide `CancelScope.__exit__()` when `shield=True`) and thus both
`debug_func`s must accept it 🤦
On the brighter side found out that the `TypeError` from the call-sig
mismatch was actually being swallowed entirely so add some
`.exception()` msgs for such cases to at least alert the dev they broke
stuff XD
It's been on the todo for a while and I've given up trying to properly
hide the `trio.CancelScope.__exit__()` frame for now instead opting to
just `log.pdb()` a big apology XD
Users can obvi still just not use the flag and wrap `tractor.pause()` in
their own cs block if they want to avoid having to hit `'up'` in the pdb
REPL if needed in a cancelled task-scope.
Impl deatz:
- factor orig `.pause()` impl into new `._pause()` so that we can more tersely
wrap the original content depending on `shield: bool` input; only open
the cancel-scope when shield is set to avoid aforemented extra strack
frame annoyance.
- pass through `shield` to underlying `_pause` and `debug_func()` so we
can actually know when so log our apology.
- add a buncha notes to new `.pause()` wrapper regarding the inability
to hide the cancel-scope `.__exit__()`, inluding that overriding the
code in `trio._core._run.CancelScope` doesn't seem to solve the issue
either..
Unrelated `maybe_wait_for_debugger()` tweaks:
- don't read `Lock.global_actor_in_debug` more then needed, rename local
read var to `in_debug` (since it can also hold the root actor uid, not
just sub-actors).
- shield the `await debug_complete.wait()` since ideally we avoid the
root cancellation child-actors in debug even when the root calls this
func in a cancelled scope.
Since this was changed as part of overall project wide logging format
updates, and i ended up changing the both the crash and pause `.pdb()`
msgs to include some multi-line-ascii-"stuff", might as well make the
pre-prompt checks in the test suite more flexible to match.
As such, this exposes 2 new constants inside the `.devx._debug` mod:
- `._pause_msg: str` for the pre `tractor.pause()` header emitted via
`log.pdb()` and,
- `._crash_msg: str` for the pre `._post_mortem()` equiv when handling
errors in debug mode.
Adjust the test suite to use these values and thus make us more capable
to absorb changes in the future as well:
- add a new `in_prompt_msg()` predicate, very similar to `assert_before()`
but minus `assert`s which takes in a `parts: list[str]` to match
in the pre-prompt stdout.
- delegate to `in_prompt_msg()` in `assert_before()` since it was mostly
duplicate minus `assert`.
- adjust all previous `<patt> in before` asserts to instead use
`in_prompt_msg()` with separated pre-prompt-header vs. actor-name
`parts`.
- use new `._pause/crash_msg` values in all such calls including any
`assert_before()` cases.
Allow callers to stick in a header to the `.pdb()` level emitted msg(s)
such that any "waiting status" content is only shown if the caller
actually get's blocked waiting for the debug lock; use it inside the
`._spawn` sub-process reaper call.
Also, return early if `Lock.global_actor_in_debug == None` and thus
only enter the poll loop when actually needed, consequently raise
if we fall through the loop without acquisition.
When entered by the root actor avoid excessive polling cycles by,
- blocking on the `Lock.no_remote_has_tty: trio.Event` and breaking
*immediately* when set (though we should really also lock
it from the root right?) to avoid extra loops..
- shielding the `await trio.sleep(poll_delay)` call to avoid any local
cancellation causing the (presumably root-actor task) caller to move
on (possibly to cancel its children) and instead to continue
poll-blocking until the lock is actually released by its user.
- `break` the poll loop immediately if no remote locker is detected.
- use `.pdb()` level for reporting lock state changes.
Also add a #TODO to handle calls by non-root actors as it pertains to
Implement it like you'd expect using simply a wrapping
`trio.CancelScope` which is itself shielded by the input `shield: bool`
B)
There's seemingly still some issues with the frame selection when the
REPL engages and not sure how to resolve it yet but at least this does
indeed work for practical purposes. Still needs a test obviously!
Starting of with just a `typer` (and thus transitively `click`)
`typer.Typer.callback` hook which allows passthrough of the `--ll
<loglevel: str>` and `--pdb <debug_mode: bool>` flags for use when
building CLIs that use the runtime Bo
Still needs lotsa refinement and obviously better docs but, the doc
string for `load_runtime_vars()` shows how to use the underlying
`.devx._debug.open_crash_handler()` via a wrapper that can be passed the
`--pdb` flag and then enable debug mode throughout the entire actor
system.
Where `.devx` is "developer experience", a hopefully broad enough subpkg
name for all the slick stuff planned to augment working on the actor
runtime 💥
Move the `._debug` module into the new subpkg and adjust rest of core
code base to reflect import path change. Also add a new
`.devx._debug.open_crash_handler()` manager for wrapping any sync code
outside a `trio.run()` which is handy for eventual CLI addons for
popular frameworks like `click`/`typer`.
Tyler Goodlet