Mv over `ServiceMngr` from `piker` with mods
Namely distinguishing service "IPC contexts" (opened in a
subactor via a `Portal`) from just local `trio.Task`s started
and managed under the `.service_n` (more or less wrapping in the
interface of a "task-manager" style nursery - aka a one-cancels-one
supervision start).
API changes from original (`piker`) impl,
- mk `.start_service_task()` do ONLY that, start a task with a wrapping
cancel-scope and completion event.
|_ ideally this gets factored-out/re-implemented using the
task-manager/OCO-style-nursery from GH #363.
- change what was the impl of `.start_service_task()` to `.start_service_ctx()`
since it more explicitly defines the functionality of entering
`Portal.open_context()` with a wrapping cs and completion event inside
a bg task (which syncs the ctx's lifetime with termination of the
remote actor runtime).
- factor out what was a `.start_service_ctx()` closure to a new
`_open_and_supervise_service_ctx()` mod-func holding the meat of
the supervision logic.
`ServiceMngr` API brief,
- use `open_service_mngr()` and `get_service_mngr()` to acquire the
actor-global singleton.
- `ServiceMngr.start_service()` and `.cancel_service()` which allow for
straight forward mgmt of "service subactor daemons".
hilevel_serman
Tyler Goodlet
parent
f08e888138
commit
46dbe6d2fc
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@ -0,0 +1,26 @@
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# tractor: structured concurrent "actors".
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# Copyright 2024-eternity Tyler Goodlet.
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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'''
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High level design patterns, APIs and runtime extensions built on top
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of the `tractor` runtime core.
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'''
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from ._service import (
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open_service_mngr as open_service_mngr,
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get_service_mngr as get_service_mngr,
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ServiceMngr as ServiceMngr,
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)
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@ -21,18 +21,26 @@ and API.
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'''
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from __future__ import annotations
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from contextlib import (
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# asynccontextmanager as acm,
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contextmanager as cm,
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asynccontextmanager as acm,
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# contextmanager as cm,
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)
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from collections import defaultdict
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from dataclasses import (
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dataclass,
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field,
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)
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import functools
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import inspect
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from typing import (
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Callable,
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Any,
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)
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import tractor
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import trio
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from trio import TaskStatus
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from tractor import (
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log,
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ActorNursery,
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current_actor,
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ContextCancelled,
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@ -40,9 +48,7 @@ from tractor import (
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Portal,
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)
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from ._util import (
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log, # sub-sys logger
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)
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log = log.get_logger('tractor')
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# TODO: implement a `@singleton` deco-API for wrapping the below
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@ -93,11 +99,30 @@ from ._util import (
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# TODO: implement a singleton deco-API for wrapping the below
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# factory's impl for general actor-singleton use?
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#
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# @singleton
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# async def open_service_mngr(
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# **init_kwargs,
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# ) -> ServiceMngr:
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# '''
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# Note this function body is invoke IFF no existing singleton instance already
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# exists in this proc's memory.
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# '''
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# # setup
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# yield ServiceMngr(**init_kwargs)
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# # teardown
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# TODO: singleton factory API instead of a class API
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@cm
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def open_service_mngr(
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@acm
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async def open_service_mngr(
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*,
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_singleton: list[ServiceMngr|None] = [None],
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debug_mode: bool = False,
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# NOTE; since default values for keyword-args are effectively
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# module-vars/globals as per the note from,
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# https://docs.python.org/3/tutorial/controlflow.html#default-argument-values
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@ -106,27 +131,408 @@ def open_service_mngr(
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# a difference when the default is a mutable object such as
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# a list, dictionary, or instances of most classes"
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#
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_singleton: list[ServiceMngr|None] = [None],
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**init_kwargs,
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) -> ServiceMngr:
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'''
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Open a multi-subactor-as-service-daemon tree supervisor.
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Open an actor-global "service-manager" for supervising a tree
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of subactors and/or actor-global tasks.
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The delivered `ServiceMngr` is a singleton instance for each
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actor-process and is allocated on first open and never
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The delivered `ServiceMngr` is singleton instance for each
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actor-process, that is, allocated on first open and never
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de-allocated unless explicitly deleted by al call to
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`del_service_mngr()`.
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'''
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mngr: ServiceMngr|None
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if (mngr := _singleton[0]) is None:
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log.info('Allocating a new service mngr!')
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mngr = _singleton[0] = ServiceMngr(**init_kwargs)
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else:
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log.info(
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'Using extant service mngr!\n\n'
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f'{mngr!r}\n' # it has a nice `.__repr__()` of services state
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# TODO: factor this an allocation into
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# a `._mngr.open_service_mngr()` and put in the
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# once-n-only-once setup/`.__aenter__()` part!
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# -[ ] how to make this only happen on the `mngr == None` case?
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# |_ use `.trionics.maybe_open_context()` (for generic
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# async-with-style-only-once of the factory impl, though
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# what do we do for the allocation case?
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# / `.maybe_open_nursery()` (since for this specific case
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# it's simpler?) to activate
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async with (
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tractor.open_nursery() as an,
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trio.open_nursery() as tn,
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):
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# impl specific obvi..
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init_kwargs.update({
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'actor_n': an,
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'service_n': tn,
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})
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mngr: ServiceMngr|None
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if (mngr := _singleton[0]) is None:
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log.info('Allocating a new service mngr!')
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mngr = _singleton[0] = ServiceMngr(**init_kwargs)
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# TODO: put into `.__aenter__()` section of
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# eventual `@singleton_acm` API wrapper.
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#
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# assign globally for future daemon/task creation
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mngr.actor_n = an
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mngr.service_n = tn
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else:
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assert (
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mngr.actor_n
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and
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mngr.service_tn
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)
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log.info(
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'Using extant service mngr!\n\n'
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f'{mngr!r}\n' # it has a nice `.__repr__()` of services state
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)
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try:
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# NOTE: this is a singleton factory impl specific detail
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# which should be supported in the condensed
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# `@singleton_acm` API?
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mngr.debug_mode = debug_mode
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yield mngr
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finally:
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# TODO: is this more clever/efficient?
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# if 'samplerd' in mngr.service_tasks:
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# await mngr.cancel_service('samplerd')
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tn.cancel_scope.cancel()
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def get_service_mngr() -> ServiceMngr:
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'''
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Try to get the singleton service-mngr for this actor presuming it
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has already been allocated using,
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.. code:: python
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async with open_<@singleton_acm(func)>() as mngr`
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... this block kept open ...
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If not yet allocated raise a `ServiceError`.
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'''
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# https://stackoverflow.com/a/12627202
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# https://docs.python.org/3/library/inspect.html#inspect.Signature
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maybe_mngr: ServiceMngr|None = inspect.signature(
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open_service_mngr
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).parameters['_singleton'].default[0]
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if maybe_mngr is None:
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raise RuntimeError(
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'Someone must allocate a `ServiceMngr` using\n\n'
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'`async with open_service_mngr()` beforehand!!\n'
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)
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with mngr:
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yield mngr
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return maybe_mngr
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# TODO: we need remote wrapping and a general soln:
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# - factor this into a ``tractor.highlevel`` extension # pack for the
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# library.
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# - wrap a "remote api" wherein you can get a method proxy
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# to the pikerd actor for starting services remotely!
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# - prolly rename this to ActorServicesNursery since it spawns
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# new actors and supervises them to completion?
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@dataclass
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class ServiceMngr:
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'''
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A multi-subactor-as-service manager.
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Spawn, supervise and monitor service/daemon subactors in a SC
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process tree.
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'''
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actor_n: ActorNursery
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service_n: trio.Nursery
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debug_mode: bool = False # tractor sub-actor debug mode flag
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service_tasks: dict[
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str,
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tuple[
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trio.CancelScope,
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Context,
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Portal,
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trio.Event,
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]
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] = field(default_factory=dict)
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# internal per-service task mutexs
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_locks = defaultdict(trio.Lock)
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# TODO, unify this interface with our `TaskManager` PR!
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#
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#
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async def start_service_task(
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self,
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name: str,
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# TODO: typevar for the return type of the target and then
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# use it below for `ctx_res`?
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fn: Callable,
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allow_overruns: bool = False,
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**ctx_kwargs,
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) -> tuple[
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trio.CancelScope,
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Any,
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trio.Event,
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]:
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async def _task_manager_start(
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task_status: TaskStatus[
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tuple[
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trio.CancelScope,
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trio.Event,
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]
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] = trio.TASK_STATUS_IGNORED,
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) -> Any:
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task_cs = trio.CancelScope()
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task_complete = trio.Event()
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with task_cs as cs:
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task_status.started((
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cs,
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task_complete,
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))
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try:
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await fn()
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except trio.Cancelled as taskc:
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log.cancel(
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f'Service task for `{name}` was cancelled!\n'
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# TODO: this would be a good spot to use
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# a respawn feature Bo
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)
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raise taskc
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finally:
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task_complete.set()
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(
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cs,
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complete,
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) = await self.service_n.start(_task_manager_start)
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# store the cancel scope and portal for later cancellation or
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# retstart if needed.
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self.service_tasks[name] = (
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cs,
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None,
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None,
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complete,
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)
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return (
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cs,
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complete,
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)
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async def start_service_ctx(
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self,
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name: str,
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portal: Portal,
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# TODO: typevar for the return type of the target and then
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# use it below for `ctx_res`?
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target: Callable,
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**ctx_kwargs,
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) -> tuple[
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trio.CancelScope,
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Context,
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Any,
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]:
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cs, sub_ctx, complete, started = await self.service_n.start(
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functools.partial(
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self._open_and_supervise_service_ctx,
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name=name,
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target=target,
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portal=portal,
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**ctx_kwargs,
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)
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)
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# store the cancel scope and portal for later cancellation or
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# retstart if needed.
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self.service_tasks[name] = (cs, sub_ctx, portal, complete)
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return (
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cs,
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sub_ctx,
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started,
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)
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||||
async def _open_and_supervise_service_ctx(
|
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self,
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name: str,
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target: Callable, # TODO, type for `@tractor.context` requirement
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portal: Portal,
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allow_overruns: bool = False,
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task_status: TaskStatus[
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tuple[
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trio.CancelScope,
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Context,
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||||
trio.Event,
|
||||
Any,
|
||||
]
|
||||
] = trio.TASK_STATUS_IGNORED,
|
||||
**ctx_kwargs,
|
||||
|
||||
) -> Any:
|
||||
'''
|
||||
Open a context in a service sub-actor, add to a stack
|
||||
that gets unwound at ``pikerd`` teardown.
|
||||
|
||||
This allows for allocating long-running sub-services in our main
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||||
daemon and explicitly controlling their lifetimes.
|
||||
|
||||
'''
|
||||
# TODO: use the ctx._scope directly here instead?
|
||||
# -[ ] actually what semantics do we expect for this
|
||||
# usage!?
|
||||
with trio.CancelScope() as cs:
|
||||
try:
|
||||
async with portal.open_context(
|
||||
target,
|
||||
allow_overruns=allow_overruns,
|
||||
**ctx_kwargs,
|
||||
|
||||
) as (ctx, started):
|
||||
|
||||
# unblock once the remote context has started
|
||||
complete = trio.Event()
|
||||
task_status.started((
|
||||
cs,
|
||||
ctx,
|
||||
complete,
|
||||
started,
|
||||
))
|
||||
log.info(
|
||||
f'`pikerd` service {name} started with value {started}'
|
||||
)
|
||||
# wait on any context's return value
|
||||
# and any final portal result from the
|
||||
# sub-actor.
|
||||
ctx_res: Any = await ctx.wait_for_result()
|
||||
|
||||
# NOTE: blocks indefinitely until cancelled
|
||||
# either by error from the target context
|
||||
# function or by being cancelled here by the
|
||||
# surrounding cancel scope.
|
||||
return (
|
||||
await portal.wait_for_result(),
|
||||
ctx_res,
|
||||
)
|
||||
|
||||
except ContextCancelled as ctxe:
|
||||
canceller: tuple[str, str] = ctxe.canceller
|
||||
our_uid: tuple[str, str] = current_actor().uid
|
||||
if (
|
||||
canceller != portal.chan.uid
|
||||
and
|
||||
canceller != our_uid
|
||||
):
|
||||
log.cancel(
|
||||
f'Actor-service `{name}` was remotely cancelled by a peer?\n'
|
||||
|
||||
# TODO: this would be a good spot to use
|
||||
# a respawn feature Bo
|
||||
f'-> Keeping `pikerd` service manager alive despite this inter-peer cancel\n\n'
|
||||
|
||||
f'cancellee: {portal.chan.uid}\n'
|
||||
f'canceller: {canceller}\n'
|
||||
)
|
||||
else:
|
||||
raise
|
||||
|
||||
finally:
|
||||
# NOTE: the ctx MUST be cancelled first if we
|
||||
# don't want the above `ctx.wait_for_result()` to
|
||||
# raise a self-ctxc. WHY, well since from the ctx's
|
||||
# perspective the cancel request will have
|
||||
# arrived out-out-of-band at the `Actor.cancel()`
|
||||
# level, thus `Context.cancel_called == False`,
|
||||
# meaning `ctx._is_self_cancelled() == False`.
|
||||
# with trio.CancelScope(shield=True):
|
||||
# await ctx.cancel()
|
||||
await portal.cancel_actor() # terminate (remote) sub-actor
|
||||
complete.set() # signal caller this task is done
|
||||
self.service_tasks.pop(name) # remove mngr entry
|
||||
|
||||
async def cancel_service(
|
||||
self,
|
||||
name: str,
|
||||
|
||||
) -> Any:
|
||||
'''
|
||||
Cancel the service task and actor for the given ``name``.
|
||||
|
||||
'''
|
||||
log.info(f'Cancelling `pikerd` service {name}')
|
||||
cs, sub_ctx, portal, complete = self.service_tasks[name]
|
||||
|
||||
# cs.cancel()
|
||||
await sub_ctx.cancel()
|
||||
await complete.wait()
|
||||
|
||||
if name in self.service_tasks:
|
||||
# TODO: custom err?
|
||||
# raise ServiceError(
|
||||
raise RuntimeError(
|
||||
f'Service actor for {name} not terminated and/or unknown?'
|
||||
)
|
||||
|
||||
# assert name not in self.service_tasks, \
|
||||
# f'Serice task for {name} not terminated?'
|
||||
|
||||
async def start_service(
|
||||
self,
|
||||
daemon_name: str,
|
||||
ctx_ep: Callable, # kwargs must `partial`-ed in!
|
||||
# ^TODO, type for `@tractor.context` deco-ed funcs!
|
||||
|
||||
debug_mode: bool = False,
|
||||
**tractor_actor_kwargs,
|
||||
|
||||
) -> Context:
|
||||
'''
|
||||
Start a "service" task in a (new) sub-actor and manage its
|
||||
lifetime indefinitely until termination.
|
||||
|
||||
Service actors can be cancelled (and thus shutdown) using
|
||||
`.cancel_service()`.
|
||||
|
||||
'''
|
||||
entry: tuple|None = self.service_tasks.get(daemon_name)
|
||||
if entry:
|
||||
(cs, sub_ctx, portal, complete) = entry
|
||||
return sub_ctx
|
||||
|
||||
if daemon_name not in self.service_tasks:
|
||||
portal: Portal = await self.actor_n.start_actor(
|
||||
daemon_name,
|
||||
debug_mode=( # maybe set globally during allocate
|
||||
debug_mode
|
||||
or
|
||||
self.debug_mode
|
||||
),
|
||||
**tractor_actor_kwargs,
|
||||
)
|
||||
ctx_kwargs: dict[str, Any] = {}
|
||||
if isinstance(ctx_ep, functools.partial):
|
||||
ctx_kwargs: dict[str, Any] = ctx_ep.keywords
|
||||
ctx_ep: Callable = ctx_ep.func
|
||||
|
||||
(
|
||||
cs,
|
||||
sub_ctx,
|
||||
started,
|
||||
) = await self.start_service_ctx(
|
||||
name=daemon_name,
|
||||
portal=portal,
|
||||
target=ctx_ep,
|
||||
**ctx_kwargs,
|
||||
)
|
||||
|
||||
return sub_ctx
|
||||
|
|
|
|||
Loading…
Reference in New Issue