Turns out we do want per-task inheritance particularly if there's to be
per `Context` dynamic mutation of the spec; we don't want mutation in
some task to affect any parent/global setting.
Turns out since we use a common "feeder task" in the rpc loop, we need to
offer a per `Context` payload decoder sys anyway in order to enable
per-task controls for inter-actor multi-task-ctx scenarios.
As per some newly added features and APIs:
- pass `portal: Portal` to `Actor.start_remote_task()` from
`open_context_from_portal()` marking `Portal.open_context()` as
always being the "parent" task side.
- add caller tracing via `.devx._code.CallerInfo/.find_caller_info()`
called in `mk_context()` and (for now) a `__runtimeframe__: int = 2`
inside `open_context_from_portal()` such that any enter-er of
`Portal.open_context()` will be reported.
- pass in a new `._caller_info` attr which is used in 2 new meths:
- `.repr_caller: str` for showing the name of the app-code-func.
- `.repr_api: str` for showing the API ep, which for now we just
hardcode to `Portal.open_context()` since ow its gonna show the mod
func name `open_context_from_portal()`.
- use those new props ^ in the `._deliver_msg()` flow body log msg
content for much clearer msg-flow tracing Bo
- add `Context._cancel_on_msgerr: bool` to toggle whether
a delivered `MsgTypeError` should trigger a `._scope.cancel()` call.
- also (temporarily) add separate `.cancel()` emissions for both cases
as i work through hacking out the maybe `MsgType.pld: Raw` support.
Starting with a little sub-sys for tracing caller frames by marking them
with a dunder var (`__runtimeframe__` by default) and then scanning for
that frame such that code that is *calling* our APIs can be reported
easily in logging / tracing output.
New APIs:
- `find_caller_info()` which does the scan and delivers a,
- `CallerInfo` which (attempts) to expose both the runtime frame-info
and frame of the caller func along with `NamespacePath` properties.
Probably going to re-implement the dunder var bit as a decorator later
so we can bind in the literal func-object ref instead of trying to look
it up with `get_class_from_frame()`, since it's kinda hacky/non-general
and def doesn't work for closure funcs..
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()`).
Since obvi we don't want to just only see the trace in the root most of
the time ;)
Currently the sig keeps firing twice in the root though, and i'm not
sure why yet..
- Drop `test_msg_spec_xor_pld_spec()` since we no longer support
`ipc_msg_spec` arg to `mk_codec()`.
- Expect `MsgTypeError`s around `.open_context()` calls when
`add_codec_hooks == False`.
- toss in some `.pause()` points in the subactor ctx body whilst hacking
out a `.pld` protocol for debug mode TTY locking.
Such that the top level `maybe_enable_greenback` from
`open_root_actor()` can toggle the entire actor tree's usage.
Read the rtv in `._rpc` tasks and only enable if set.
Also, rigor up the `._rpc.process_messages()` loop to handle `Error()`
and `case _:` separately such that we now raise an explicit rte for
unknown / invalid msgs. Use "parent" / "child" for side descriptions in
loop comments and put a fat comment before the `StartAck` in `_invoke()`.
Instead of `allow_msg_keys` since we've fully flipped over to
struct-types for msgs in the runtime.
- drop the loop from `MsgStream.receive_nowait()` since
`Yield/Return.pld` getting will handle both (instead of a loop of
`dict`-key reads).
Which matches with renaming `.payload_msg` -> `.expected_msg` which is
the value we attempt to construct from a vanilla-msgppack
decode-to-`dict` and then construct manually into a `MsgType` using
`.msg.types.from_dict_msg()`. Add a todo to use new `use_pretty` flag
which currently conflicts with `._exceptions.pformat_boxed_type()`
prefix formatting..
Add a bit of special handling for msg-type-errors with a dedicated
log-msg detailing which `.side: str` is the sender/causer and avoiding
a `._scope.cancel()` call in such cases since the local task might be
written to handle and tolerate the badly (typed) IPC msg.
As part of ^, change the ctx task-pair "side" semantics from "caller" ->
"callee" to be "parent" -> "child" which better matches the
cross-process SC-linked-task supervision hierarchy, and
`trio.Nursery.parent_task`; in `trio` the task that opens a nursery is
also named the "parent".
Impl deats / fixes around the `.side` semantics:
- ensure that `._portal: Portal` is set ASAP after
`Actor.start_remote_task()` such that if the `Started` transaction
fails, the parent-vs.-child sides are still denoted correctly (since
`._portal` being set is the predicate for that).
- add a helper func `Context.peer_side(side: str) -> str:` which inverts
from "child" to "parent" and vice versa, useful for logging info.
Other tweaks:
- make `_drain_to_final_msg()` return a tuple of a maybe-`Return` and
the list of other `pre_result_drained: list[MsgType]` such that we
don't ever have to warn about the return msg getting captured as
a pre-"result" msg.
- Add some strictness flags to `.started()` which allow for toggling
whether to error or warn log about mismatching roundtripped `Started`
msgs prior to IPC transit.
Display the new `MsgCodec.pld_spec_str` and format the incorrect field
value to be placed entirely (txt block wise) right of the "type annot"
part of the line:
Iow if you had a bad `dict` value where something else should be it'd
look something like this:
<Started(
|_pld: NamespacePath = {'cid': '3e0ca00c-7d32-4d2a-a0c2-ac2e12453871',
'locked': True,
'msg_type': 'LockStatus',
'subactor_uid': ['sub', 'af7ccb69-1dab-491f-84f7-2ec42c32d137']}
- add some `tb_str: str` indent-prefix args for diff indent levels for the
body vs. the surrounding "ascii box".
- ^-use it-^ from `RemoteActorError.__repr()__` obvi.
- use new `msg.types.from_dict_msg()` in impl of
`MsgTypeError.payload_msg`, handy for showing what the message "would
have looked like in `Struct` form" had it not failed it's type
constraints.
Sure makes console grokability a lot better by showing only the
customizeable fields.
Further, clean up `mk_codec()` a bunch by removing the `ipc_msg_spec`
param since we don't plan to support another msg-set (for now) which
allows cleaning out a buncha logic that was mostly just a source of
bugs..
Also,
- add temporary `log.info()` around codec application.
- throw in some sanity `assert`s to `limit_msg_spec()`.
- add but mask out the `extend_msg_spec()` idea since it seems `msgspec`
won't allow `Decoder.type` extensions when using a custom `dec_hook()`
for some extension type.. (not sure what approach to take here yet).
Handy for re-constructing a struct-`MsgType` from a `dict` decoded from
wire-bytes wherein the msg failed to decode normally due to a field type
error but you'd still like to show the "potential" msg in struct form,
say inside a `MsgTypeError`'s meta data.
Supporting deats:
- add a `.msg.types.from_dict_msg()` to implement it (the helper).
- also a `.msg.types._msg_table: dict[str, MsgType]` for supporting this
func ^ as well as providing just a general `MsgType`-by-`str`-name
lookup.
Unrelated:
- Drop commented idea for still supporting `dict`-msg set via
`enc/dec_hook()`s that would translate to/from `MsgType`s, but that
would require a duplicate impl in the runtime.. so eff that XD
Not sure if this is a good tactic (yet) but it at least covers us from
getting user's confused by `breakpoint()` usage causing REPL clobbering.
Always set an explicit rte raising breakpoint hook such that the user
realizes they can't use `.pause_from_sync()` without enabling debug
mode.
** CHERRY-PICK into `pause_from_sync_w_greenback` branch! **
Mostly removing commented (and replaced) code blocks lingering from the
ctxc semantics work and new typed-msg-spec `MsgType`s handling AND use
the new `._exceptions.pack_from_raise()` helper to construct
`StreamOverrun` msgs.
Deaterz:
- clean out the drain loop now that it's implemented to handle our
struct msg types including the `dict`-msg bits left in as
fallback-reminders, any notes/todos better summarized at the top of
their blocks, remove any `_final_result_is_set()` related duplicate/legacy
tidbits.
- use a `case Error()` block in drain loop with fallthrough to `_:`
always resulting in an rte raise.
- move "XXX" notes into the doc-string for `._deliver_msg()` as
a "rules" section.
- use `match:` syntax for logging the `result_or_err: MsgType` outcome
from the final `.result()` call inside `open_context_from_portal()`.
- generally speaking use `MsgType` type annotations throughout!
Such that `Channel.recv()` + `MsgpackTCPStream.recv()` originating
msg-type-errors are not raised at the IPC transport layer but instead
relayed up the runtime stack for eventual handling by user-app code via
the `Context`/`MsgStream` layer APIs.
This design choice leads to a substantial amount of flexibility and
modularity, and avoids `MsgTypeError` handling policies from being
coupled to a particular backend IPC transport layer:
- receive-side msg-type errors, as can be raised and handled in the
`.open_stream()` "nasty" phase of a ctx, whilst being packed at the
`MsgCodec`/transport layer (keeping the underlying src decode error
coupled to the specific transport + interchange lib) and then relayed
upward to app code for custom handling like a normal Error` msg.
- the policy options for handling such cases could be implemented as
`@acm` wrappers around `.open_context()`/`.open_stream()` blocks (and
their respective delivered primitives) OR just plain old async
generators around `MsgStream.receive()` such that both built-in policy
handling and custom user-app solutions can be swapped without touching
any `tractor` internals or providing specialized "registry APIs".
-> eg. the ignore and relay-invalid-msg-to-sender approach can be more
easily implemented as embedded `try: except MsgTypeError:` blocks
around `MsgStream.receive()` possibly applied as either of an
injected wrapper type around a stream or an async gen that `async
for`s from the stream.
- any performance based AOT-lang extensions used to implement a policy
for handling recv-side errors space can avoid knowledge of the lower
level IPC `Channel` (and-downward) primitives.
- `Context` consuming code can choose to let all msg-type-errs
bubble and handle them manually (like any other remote `Error`
shuttled exception).
- we can keep (as before) send-side msg type checks can be raised
locally and cause offending senders to error and adjust before the
streaming phase of an IPC ctx.
Impl (related) deats:
- obvi make `MsgpackTCPStream.recv()` yield up any `MsgTypeError`
constructed by `_mk_msg_type_err()` such that the exception will
eventually be relayed up to `._rpc.process_messages()` and from
their delivered to the corresponding ctx-task.
- in support of ^, make `Channel.recv()` detect said mtes and use the
new `pack_from_raise()` to inject the far end `Actor.uid` for the
`Error.src_uid`.
- keep raising the send side equivalent (when strict enabled) errors
inline immediately with no upward `Error` packing or relay.
- improve `_mk_msg_type_err()` cases handling with far more detailed
`MsgTypeError` "message" contents pertaining to `msgspec` specific
failure-fixing-tips and type-spec mismatch info:
* use `.from_decode()` constructor in recv-side case to inject the
non-spec decoded `msg_dict: dict` and use the new
`MsgCodec.pld_spec_str: str` when clarifying the type discrepancy
with the offending field.
* on send-side, if we detect that an unsupported field type was
described in the original `src_type_error`, AND there is no
`msgpack.Encoder.enc_hook()` set, that the real issue is likely
that the user needs to extend the codec to support the
non-std/custom type with a hook and link to `msgspec` docs.
* if one of a `src_type/validation_error` is provided, set that
error as the `.__cause__` in the new mte.
Make a new `MsgType: TypeAlias` for the union of all msg types such that
it can be used in annots throughout the code base; just make
`.msg.__msg_spec__` delegate to it.
Add some new codec methods:
- `pld_spec_str`: for the `str`-casted value of the payload spec,
generally useful in logging content.
- `msg_spec_items()`: to render a `dict` of msg types to their
`str()`-casted values with support for singling out a specific
`MsgType`, type by input `msg` instance.
- `pformat_msg_spec()`: for rendering the (partial) `.msg_spec` as
a formatted `str` useful in logging.
Oh right, add a `Error._msg_dict: dict` in support of the previous
commit (for `MsgTypeError` packing as RAEs) such that our error msg type
can house a non-type-spec decoded wire-bytes for error
reporting/analysis purposes.
Since in the receive-side error case the source of the exception is the
sender side (normally causing a local `TypeError` at decode time), might
as well bundle the error in remote-capture-style using boxing semantics
around the causing local type error raised from the
`msgspec.msgpack.Decoder.decode()` and with a traceback packed from
`msgspec`-specific knowledge of any field-type spec matching failure.
Deats on new `MsgTypeError` interface:
- includes a `.msg_dict` to get access to any `Decoder.type`-applied
load of the original (underlying and offending) IPC msg into
a `dict` form using a vanilla decoder which is normally packed into
the instance as a `._msg_dict`.
- a public getter to the "supposed offending msg" via `.payload_msg`
which attempts to take the above `.msg_dict` and load it manually into
the corresponding `.msg.types.MsgType` struct.
- a constructor `.from_decode()` to make it simple to build out error
instances from a failed decode scope where the aforementioned
`msgdict: dict` from the vanilla decode can be provided directly.
- ALSO, we now pack into `MsgTypeError` directly just like ctxc in
`unpack_error()`
This also completes the while-standing todo for `RemoteActorError` to
contain a ref to the underlying `Error` msg as `._ipc_msg` with public
`@property` access that `defstruct()`-creates a pretty struct version
via `.ipc_msg`.
Internal tweaks for this include:
- `._ipc_msg` is the internal literal `Error`-msg instance if provided
with `.ipc_msg` the dynamic wrapper as mentioned above.
- `.__init__()` now can still take variable `**extra_msgdata` (similar
to the `dict`-msgdata as before) to maintain support for subtypes
which are constructed manually (not only by `pack_error()`) and insert
their own attrs which get placed in a `._extra_msgdata: dict` if no
`ipc_msg: Error` is provided as input.
- the `.msgdata` is now a merge of any `._extra_msgdata` and
a `dict`-casted form of any `._ipc_msg`.
- adjust all previous `.msgdata` field lookups to try equivalent field
reads on `._ipc_msg: Error`.
- drop default single ws indent from `.tb_str` and do a failover lookup
to `.msgdata` when `._ipc_msg is None` for the manually constructed
subtype-instance case.
- add a new class attr `.extra_body_fields: list[str]` to allow subtypes
to declare attrs they want shown in the `.__repr__()` output, eg.
`ContextCancelled.canceller`, `StreamOverrun.sender` and
`MsgTypeError.payload_msg`.
- ^-rework defaults pertaining to-^ with rename from
`_msgdata_keys` -> `_ipcmsg_keys` with latter now just loading directly
from the `Error` fields def and `_body_fields: list[str]` just taking
that value and removing the not-so-useful-in-REPL or already shown
(i.e. `.tb_str: str`) field names.
- add a new mod level `.pack_from_raise()` helper for auto-boxing RAE
subtypes constructed manually into `Error`s which is normally how
`StreamOverrun` and `MsgTypeError` get created in the runtime.
- in support of the above expose a `src_uid: tuple` override to
`pack_error()` such that the runtime can provide any remote actor id
when packing a locally-created yet remotely-caused RAE subtype.
- adjust all typing to expect `Error`s over `dict`-msgs.
Adjust some tests to match these changes:
- context and inter-peer-cancel tests to make their `.msgdata` related
checks against the new `.ipc_msg` as well and `.tb_str` directly.
- toss in an extra sleep to `sleep_a_bit_then_cancel_peer()` to keep the
'canceller' ctx child task cancelled by it's parent in the 'root' for
the rte-raised-during-ctxc-handling case (apparently now it's
returning too fast, cool?).
Better describes the internal RPC impl/latest-architecture with the msgs
delivered being those which either define a `.pld: PayloadT` that gets
passed up to user code, or the error-msg subset that similarly is raised
in a ctx-linked task.
These are likely temporary changes but still needed to actually see the
desired/correct failures (of which 5 of 6 tests are supposed to fail rn)
mostly to do with `Start` and `Return` msgs which are invalid under each
test's applied msg-spec.
Tweak set here:
- bit more `print()`s in root and sub for grokin test flow.
- never use `pytes.fail()` in subactor.. should know this by now XD
- comment out some bits that can't ever pass rn and make the underlying
expected failues harder to grok:
- the sub's child-side-of-ctx task doing sends should only fail
for certain msg types like `Started` + `Return`, `Yield`s are
processed receiver/parent side.
- don't expect `sent` list to match predicate set for the same reason
as last bullet.
The outstanding msg-type-semantic validation questions are:
- how to handle `.open_context()` with an input `kwargs` set that
doesn't adhere to the currently applied msg-spec?
- should the initial `@acm` entry fail before sending to the child
side?
- where should received `MsgTypeError`s be raised, at the `MsgStream`
`.receive()` or lower in the stack?
- i'm thinking we should mk `MsgTypeError` derive from
`RemoteActorError` and then have it be delivered as an error to the
`Context`/`MsgStream` for per-ctx-task handling; would lead to more
flexible/modular policy overrides in user code outside any defaults
we provide.
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()`.
Add both the `.send()` and `.recv()` handling blocks to a common
`_raise_msg_type_err()` which includes detailed error msg formatting:
- the `.recv()` side case does introspection of the `Msg` fields and
attempting to report the exact (field type related) issue
- `.send()` side does some boxed-error style tb formatting like
`RemoteActorError`.
- add a `strict_types: bool` to `.send()` to allow for just
warning on bad inputs versus raising, but always raise from any
`Encoder` type error.
As detailed in the surrounding notes, it's pretty advantageous to always
have the child context task ensure the first msg it relays back is
msg-type checked against the current spec and thus `MsgCodec`. Implement
the check via a simple codec-roundtrip of the `Started` msg such that
the `.pld` payload is always validated before transit. This ensures the
child will fail early and notify the parent before any streaming takes
place (i.e. the "nasty" dialog protocol phase).
The main motivation here is to avoid inter-actor task syncing bugs that
are hard(er) to recover from and/or such as if an invalid typed msg is
sent to the parent, who then ignores it (depending on config), and then
the child thinks the parent is in some presumed state while the parent
is still thinking a first msg has yet to arrive. Doing the stringent
check on the sender side (i.e. the child is sending the "first"
application msg via `.started()`) avoids/sidesteps dealing with such
syncing/coordinated-state problems by keeping the entire IPC dialog in
a "cheap" or "control" style transaction up until a stream is opened.
Iow, the parent task's `.open_context()` block entry can't occur until
the child side is definitely (as much as is possible with IPC msg type
checking) in a correct state spec wise. During any streaming phase in
the dialog the msg-type-checking is NOT done for performance (the
"nasty" protocol phase) and instead any type errors are relayed back
from the receiving side. I'm still unsure whether to take the same
approach on the `Return` msg, since at that point erroring early doesn't
benefit the parent task if/when a msg-type error occurs? Definitely more
to ponder and tinker out here..
Impl notes:
- a gotcha with the roundtrip-codec-ed msg is that it often won't match
the input `value` bc in the `msgpack` case many native python
sequence/collection types will map to a common array type due to the
surjection that `msgpack`'s type-sys imposes.
- so we can't assert that `started == rt_started` but it may be useful
to at least report the diff of the type-reduced payload so that the
caller can at least be notified how the input `value` might be
better type-casted prior to call, for ex. pre-casting to `list`s.
- added a `._strict_started: bool` that could provide the stringent
checking if desired in the future.
- on any validation error raise our `MsgTypeError` from it.
- ALSO change over the lingering `.send_yield()` deprecated meth body
to use a `Yield()`.
Such that the current `kwargs: dict` field can eventually be strictly
msg-typed (eventually directly from a `@context` def) using modern typed
python's hippest syntactical approach B)
Also proto a new `CancelAck(Return)` subtype msg for supporting msg-spec
agnostic `Actor.cancel_xx()` method calls in the runtime such that
a user can't break cancellation (and thus SC) by dynamically setting
a codec that doesn't allow `bool` results (as an eg. in this case).
Note that the msg isn't used yet in `._rpc` but that's a comin!
Set a diff `Msg.pld` spec per test and then send multiple types to
a child actor making sure the child can only send certain types over
a stream and fails with validation or decode errors ow. The test is also
param-ed both with and without hooks demonstrating how a custom type,
`NamespacePath`, needs them for effective use. The subactor IPC context
child is passed a `expect_ipc_send: dict` which relays the values along
with their expected `.send()`-ability.
Deats on technical refinements:
------ - ------
- added a `iter_maybe_sends()` send-value-as-msg-auditor and predicate
generator (literally) so as to be able to pre-determine if given the
current codec and `send_values` which values are expected to be IPC
transmittable.
- as per ^, the diff value-msgs are first round-tripped inside
a `Started` msg using the configured codec in the parent/root actor
before bothering with using IPC primitives + a subactor; this is how
the `expect_ipc_send` table is generated initially.
- for serializing the specs (`Union[Type]`s as required by `msgspec`),
added a pair of codec hooks: `enc/dec_type_union()` (that ideally we
move into a `.msg` submod eventually) which code the type-values as
a `list[str]` of names.
- the `dec_` hook had to be modified to NOT raise an error when an
invalid/unhandled value arrives, this is because we do NOT want the
RPC msg handling loop to raise on the `async for msg in chan:` and
instead prefer to ignore and warn (for now, but eventually respond
with error msg - see notes in hook body) these msgs when sent during
a streaming phase; `Context.started()` will however error on a bad
input for the current msg-spec since it is part of the "cheap"
dialog (again see notes in `._context`) wherein the `Started` msg
is always roundtripped prior to `Channel.send()` to guarantee
the child adheres to its own spec.
- tossed in lotsa `print()`s for console groking of the run progress.
Further notes on typed-msging breaking cancellation:
------ - ------
- turns out since the runtime's cancellation implementation, being done
with `Actor.cancel()` methods and friends will actually break when
a stringent spec is applied (eg. a single type-spec) since the return
values from said methods are generally `bool`s..
- this means we do indeed need special handling of "runtime RPC method
invocations" since ideally a user's msg-spec choices do not break core
functionality on them XD
=> The obvi solution is to add a/some special sub-`Msg` types for such
cases, possibly just a `RuntimeReturn(Return)` type that will always
include a `.pld: bool` for these cancel methods such that their
results are always handled without msg type errors.
More to come on a (hopefully) elegant solution to that last bit!
Tyler Goodlet