Mainly expanding out the runtime endpoints for cancellation to separate
cases and flattening them with the main RPC-request-invoke block, moving
the non-cancel runtime case (where we call `getattr(actor, funcname)`)
inside the main `Start` case (for now) which branches on `ns=="self"`.
Also, add a new IPC msg `class CancelAck(Return):` which is always
included in the default msg-spec such that runtime cancellation (and
eventually all) endpoints return that msg (instead of a `Return`) and
thus sidestep any currently applied `MsgCodec` such that the results
(`bool`s for most cancel methods) are never violating the current type
limit(s) on `Msg.pld`. To support this expose a new variable
`return_msg: Return|CancelAck` param from
`_invoke()`/`_invoke_non_context)()` and set it to `CancelAck` in the
appropriate endpoint case-blocks of the msg loop.
Clean out all the lingering legacy `chan.send(<dict-msg>)` commented
codez from the invoker funcs, with more cleaning likely to come B)
Pretty sure we haven't *needed it* for a while, it was always generally
hazardous in terms of IPC msg types, AND it's definitely incompatible
with a dynamically applied typed msg spec: you can't just expect
a `None` to be willy nilly handled all the time XD
For now I'm masking out all the code and leaving very detailed
surrounding notes but am not removing it quite yet in case for strange
reason it is needed by some edge case (though I haven't found according
to the test suite).
Backstory:
------ - ------
Originally (i'm pretty sure anyway) it was added as a super naive
"remote cancellation" mechanism (back before there were specific `Actor`
methods for such things) that was mostly (only?) used before IPC
`Channel` closures to "more gracefully cancel" the connection's parented
RPC tasks. Since we now have explicit runtime-RPC endpoints for
conducting remote cancellation of both tasks and full actors, it should
really be removed anyway, because:
- a `None`-msg setinel is inconsistent with other RPC endpoint handling
input patterns which (even prior to typed msging) had specific
msg-value triggers.
- the IPC endpoint's (block) implementation should use
`Actor.cancel_rpc_tasks(parent_chan=chan)` instead of a manual loop
through a `Actor._rpc_tasks.copy()`..
Deats:
- mask the `Channel.send(None)` calls from both the `Actor._stream_handler()` tail
as well as from the `._portal.open_portal()` was connected block.
- mask the msg loop endpoint block and toss in lotsa notes.
Unrelated tweaks:
- drop `Actor._debug_mode`; unused.
- make `Actor.cancel_server()` return a `bool`.
- use `.msg.pretty_struct.Struct.pformat()` to show any msg that is
ignored (bc invalid) in `._push_result()`.
Re-arranging such that element-orders are line-arranged to our new
IPC `.msg.types.Msg` fields spec in prep for replacing the current
`dict`-as-msg impls with the `msgspec.Struct` native versions!
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.
Since adding more complex inter-peer (actor) testing scenarios, we
definitely have an immediate need for `trio`'s style of "inceptions" but
for nesting `RemoteActorError`s as they're relayed through multiple
actor-IPC hops. So for example, a remote error relayed "through" some
proxy actor to another ends up packing a `RemoteActorError` into another
one such that there are 2 layers of RAEs with the first
containing/boxing an original src actor error (type).
In support of this extension to `RemoteActorError` we add:
- `get_err_type()` error type resolver helper (factored fromthe
body of `unpack_error()`) to be used whenever rendering
`.src_type`/`.boxed_type`.
- `.src_type_str: str` which is pulled from `.msgdata` and holds the
above (eventually when unpacked) type as `str`.
- `._src_type: BaseException|None` for the original
"source" actor's error as unpacked in any remote (actor's) env and
exposed as a readonly property `.src_type`.
- `.boxed_type_str: str` the same as above but for the "last" boxed
error's type; when the RAE is unpacked at its first hop this will
be **the same as** `.src_type_str`.
- `._boxed_type: BaseException` which now similarly should be "rendered"
from the below type-`str` field instead of passed in as a error-type
via `boxed_type` (though we still do for the ctxc case atm, see
notes).
|_ new sanity checks in `.__init__()` mostly as a reminder to handle
that ^ ctxc case ^ more elegantly at some point..
|_ obvi we discard the previous `suberror_type` input arg.
- fully remove the `.type`/`.type_str` properties instead expecting
usage of `.boxed_/.src_` equivalents.
- start deprecation of `.src_actor_uid` and make it delegate to new
`.src_uid`
- add `.relay_uid` propery for the last relay/hop's actor uid.
- add `.relay_path: list[str]` which holds the per-hop updated sequence
of relay actor uid's which consecutively did boxing of an RAE.
- only include `.src_uid` and `.relay_path` in reprol() output.
- factor field-to-str rendering into a new `_mk_fields_str()`
and use it in `.__repr__()`/`.reprol()`.
- add an `.unwrap()` to (attempt to) render the src error.
- rework `pack_error()` to handle inceptions including,
- packing the correct field-values for the new `boxed_type_str`, `relay_uid`,
`src_uid`, `src_type_str`.
- always updating the `relay_path` sequence with the uid of the
current actor.
- adjust `unpack_error()` to match all these changes,
- pulling `boxed_type_str` and passing any resolved `boxed_type` to
`RemoteActorError.__init__()`.
- use the new `Context.maybe_raise()` convenience method.
Adjust `._rpc` packing to `ContextCancelled(boxed_type=trio.Cancelled)`
and tweak some more log msg formats.
- `trio_typing` is nearly obsolete since `trio >= 0.23`
- `exceptiongroup` is built-in to python 3.11
- `async_generator` primitives have lived in `contextlib` for quite
a while!
Since `._runtime` was getting pretty long (> 2k LOC) and much of the RPC
low-level machinery is fairly isolated to a handful of task-funcs, it
makes sense to re-org the RPC task scheduling and driving msg loop to
its own code space.
The move includes:
- `process_messages()` which is the main IPC business logic.
- `try_ship_error_to_remote()` helper, to box local errors for the wire.
- `_invoke()`, the core task scheduler entrypoing used in the msg loop.
- `_invoke_non_context()`, holds impls for non-`@context` task starts.
- `_errors_relayed_via_ipc()` which does all error catch-n-boxing for
wire-msg shipment using `try_ship_error_to_remote()` internally.
Also inside `._runtime` improve some `Actor` methods docs.
Tyler Goodlet