1256 lines
47 KiB
Python
1256 lines
47 KiB
Python
"""
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Actor primitives and helpers
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"""
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from collections import defaultdict
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from functools import partial
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from itertools import chain
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import importlib
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import importlib.util
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import inspect
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import uuid
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import typing
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from typing import Dict, List, Tuple, Any, Optional, Union
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from types import ModuleType
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import sys
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import os
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from contextlib import ExitStack
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import warnings
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import trio # type: ignore
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from trio_typing import TaskStatus
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from async_generator import aclosing
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from ._ipc import Channel
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from ._streaming import Context
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from .log import get_logger
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from ._exceptions import (
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pack_error,
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unpack_error,
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ModuleNotExposed,
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is_multi_cancelled,
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ContextCancelled,
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TransportClosed,
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)
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from . import _debug
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from ._discovery import get_arbiter
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from ._portal import Portal
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from . import _state
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from . import _mp_fixup_main
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log = get_logger('tractor')
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class ActorFailure(Exception):
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"General actor failure"
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async def _invoke(
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actor: 'Actor',
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cid: str,
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chan: Channel,
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func: typing.Callable,
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kwargs: Dict[str, Any],
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task_status: TaskStatus[
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Union[trio.CancelScope, BaseException]
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] = trio.TASK_STATUS_IGNORED,
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):
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"""Invoke local func and deliver result(s) over provided channel.
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"""
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treat_as_gen = False
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# possible a traceback (not sure what typing is for this..)
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tb = None
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cancel_scope = trio.CancelScope()
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cs: Optional[trio.CancelScope] = None
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ctx = Context(chan, cid)
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context: bool = False
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if getattr(func, '_tractor_stream_function', False):
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# handle decorated ``@tractor.stream`` async functions
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sig = inspect.signature(func)
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params = sig.parameters
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# compat with old api
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kwargs['ctx'] = ctx
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if 'ctx' in params:
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warnings.warn(
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"`@tractor.stream decorated funcs should now declare "
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"a `stream` arg, `ctx` is now designated for use with "
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"@tractor.context",
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DeprecationWarning,
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stacklevel=2,
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)
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elif 'stream' in params:
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assert 'stream' in params
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kwargs['stream'] = ctx
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treat_as_gen = True
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elif getattr(func, '_tractor_context_function', False):
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# handle decorated ``@tractor.context`` async function
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kwargs['ctx'] = ctx
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context = True
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# errors raised inside this block are propgated back to caller
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try:
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if not (
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inspect.isasyncgenfunction(func) or
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inspect.iscoroutinefunction(func)
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):
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raise TypeError(f'{func} must be an async function!')
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coro = func(**kwargs)
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if inspect.isasyncgen(coro):
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await chan.send({'functype': 'asyncgen', 'cid': cid})
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# XXX: massive gotcha! If the containing scope
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# is cancelled and we execute the below line,
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# any ``ActorNursery.__aexit__()`` WON'T be
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# triggered in the underlying async gen! So we
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# have to properly handle the closing (aclosing)
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# of the async gen in order to be sure the cancel
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# is propagated!
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with cancel_scope as cs:
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task_status.started(cs)
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async with aclosing(coro) as agen:
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async for item in agen:
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# TODO: can we send values back in here?
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# it's gonna require a `while True:` and
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# some non-blocking way to retrieve new `asend()`
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# values from the channel:
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# to_send = await chan.recv_nowait()
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# if to_send is not None:
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# to_yield = await coro.asend(to_send)
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await chan.send({'yield': item, 'cid': cid})
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log.debug(f"Finished iterating {coro}")
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# TODO: we should really support a proper
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# `StopAsyncIteration` system here for returning a final
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# value if desired
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await chan.send({'stop': True, 'cid': cid})
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# one way @stream func that gets treated like an async gen
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elif treat_as_gen:
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await chan.send({'functype': 'asyncgen', 'cid': cid})
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# XXX: the async-func may spawn further tasks which push
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# back values like an async-generator would but must
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# manualy construct the response dict-packet-responses as
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# above
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with cancel_scope as cs:
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task_status.started(cs)
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await coro
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if not cs.cancelled_caught:
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# task was not cancelled so we can instruct the
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# far end async gen to tear down
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await chan.send({'stop': True, 'cid': cid})
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elif context:
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# context func with support for bi-dir streaming
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await chan.send({'functype': 'context', 'cid': cid})
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async with trio.open_nursery() as scope_nursery:
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ctx._scope_nursery = scope_nursery
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cs = scope_nursery.cancel_scope
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task_status.started(cs)
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try:
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await chan.send({'return': await coro, 'cid': cid})
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except trio.Cancelled as err:
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tb = err.__traceback__
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if cs.cancelled_caught:
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# TODO: pack in ``trio.Cancelled.__traceback__`` here
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# so they can be unwrapped and displayed on the caller
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# side!
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fname = func.__name__
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if ctx._cancel_called:
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msg = f'{fname} cancelled itself'
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elif cs.cancel_called:
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msg = (
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f'{fname} was remotely cancelled by its caller '
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f'{ctx.chan.uid}'
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)
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# task-contex was cancelled so relay to the cancel to caller
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raise ContextCancelled(
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msg,
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suberror_type=trio.Cancelled,
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)
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else:
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# regular async function
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await chan.send({'functype': 'asyncfunc', 'cid': cid})
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with cancel_scope as cs:
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task_status.started(cs)
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await chan.send({'return': await coro, 'cid': cid})
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except (Exception, trio.MultiError) as err:
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if not is_multi_cancelled(err):
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log.exception("Actor crashed:")
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# TODO: maybe we'll want different "levels" of debugging
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# eventualy such as ('app', 'supervisory', 'runtime') ?
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# if not isinstance(err, trio.ClosedResourceError) and (
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# if not is_multi_cancelled(err) and (
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entered_debug: bool = False
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if not isinstance(err, ContextCancelled) or (
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isinstance(err, ContextCancelled) and ctx._cancel_called
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):
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# XXX: is there any case where we'll want to debug IPC
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# disconnects as a default?
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#
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# I can't think of a reason that inspecting
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# this type of failure will be useful for respawns or
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# recovery logic - the only case is some kind of strange bug
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# in our transport layer itself? Going to keep this
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# open ended for now.
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entered_debug = await _debug._maybe_enter_pm(err)
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if not entered_debug:
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log.exception("Actor crashed:")
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# always ship errors back to caller
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err_msg = pack_error(err, tb=tb)
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err_msg['cid'] = cid
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try:
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await chan.send(err_msg)
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except trio.ClosedResourceError:
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# if we can't propagate the error that's a big boo boo
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log.error(
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f"Failed to ship error to caller @ {chan.uid} !?"
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)
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if cs is None:
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# error is from above code not from rpc invocation
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task_status.started(err)
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finally:
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# RPC task bookeeping
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try:
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scope, func, is_complete = actor._rpc_tasks.pop((chan, cid))
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is_complete.set()
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except KeyError:
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# If we're cancelled before the task returns then the
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# cancel scope will not have been inserted yet
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log.warning(
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f"Task {func} likely errored or cancelled before it started")
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finally:
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if not actor._rpc_tasks:
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log.runtime("All RPC tasks have completed")
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actor._ongoing_rpc_tasks.set()
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def _get_mod_abspath(module):
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return os.path.abspath(module.__file__)
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# process-global stack closed at end on actor runtime teardown
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_lifetime_stack: ExitStack = ExitStack()
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class Actor:
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"""The fundamental concurrency primitive.
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An *actor* is the combination of a regular Python process
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executing a ``trio`` task tree, communicating
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with other actors through "portals" which provide a native async API
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around various IPC transport "channels".
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"""
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is_arbiter: bool = False
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# nursery placeholders filled in by `_async_main()` after fork
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_root_n: Optional[trio.Nursery] = None
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_service_n: Optional[trio.Nursery] = None
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_server_n: Optional[trio.Nursery] = None
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# Information about `__main__` from parent
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_parent_main_data: Dict[str, str]
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_parent_chan_cs: Optional[trio.CancelScope] = None
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def __init__(
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self,
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name: str,
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*,
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enable_modules: List[str] = [],
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uid: str = None,
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loglevel: str = None,
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arbiter_addr: Optional[Tuple[str, int]] = None,
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spawn_method: Optional[str] = None
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) -> None:
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"""This constructor is called in the parent actor **before** the spawning
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phase (aka before a new process is executed).
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"""
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self.name = name
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self.uid = (name, uid or str(uuid.uuid4()))
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self._cancel_complete = trio.Event()
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self._cancel_called: bool = False
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# retreive and store parent `__main__` data which
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# will be passed to children
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self._parent_main_data = _mp_fixup_main._mp_figure_out_main()
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# always include debugging tools module
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enable_modules.append('tractor._debug')
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mods = {}
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for name in enable_modules:
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mod = importlib.import_module(name)
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mods[name] = _get_mod_abspath(mod)
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self.enable_modules = mods
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self._mods: Dict[str, ModuleType] = {}
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# TODO: consider making this a dynamically defined
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# @dataclass once we get py3.7
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self.loglevel = loglevel
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self._arb_addr = arbiter_addr
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# marked by the process spawning backend at startup
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# will be None for the parent most process started manually
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# by the user (currently called the "arbiter")
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self._spawn_method = spawn_method
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self._peers: defaultdict = defaultdict(list)
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self._peer_connected: dict = {}
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self._no_more_peers = trio.Event()
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self._no_more_peers.set()
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self._ongoing_rpc_tasks = trio.Event()
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self._ongoing_rpc_tasks.set()
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# (chan, cid) -> (cancel_scope, func)
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self._rpc_tasks: Dict[
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Tuple[Channel, str],
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Tuple[trio.CancelScope, typing.Callable, trio.Event]
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] = {}
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# map {uids -> {callids -> waiter queues}}
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self._cids2qs: Dict[
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Tuple[Tuple[str, str], str],
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Tuple[
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trio.abc.SendChannel[Any],
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trio.abc.ReceiveChannel[Any]
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]
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] = {}
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self._listeners: List[trio.abc.Listener] = []
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self._parent_chan: Optional[Channel] = None
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self._forkserver_info: Optional[
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Tuple[Any, Any, Any, Any, Any]] = None
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self._actoruid2nursery: Dict[str, 'ActorNursery'] = {} # type: ignore # noqa
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async def wait_for_peer(
|
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self, uid: Tuple[str, str]
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) -> Tuple[trio.Event, Channel]:
|
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"""Wait for a connection back from a spawned actor with a given
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``uid``.
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"""
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log.debug(f"Waiting for peer {uid} to connect")
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event = self._peer_connected.setdefault(uid, trio.Event())
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await event.wait()
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log.debug(f"{uid} successfully connected back to us")
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return event, self._peers[uid][-1]
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|
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def load_modules(self) -> None:
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"""Load allowed RPC modules locally (after fork).
|
|
|
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Since this actor may be spawned on a different machine from
|
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the original nursery we need to try and load the local module
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code (if it exists).
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"""
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try:
|
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if self._spawn_method == 'trio':
|
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parent_data = self._parent_main_data
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if 'init_main_from_name' in parent_data:
|
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_mp_fixup_main._fixup_main_from_name(
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parent_data['init_main_from_name'])
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elif 'init_main_from_path' in parent_data:
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_mp_fixup_main._fixup_main_from_path(
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parent_data['init_main_from_path'])
|
|
|
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for modpath, filepath in self.enable_modules.items():
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|
# XXX append the allowed module to the python path which
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# should allow for relative (at least downward) imports.
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sys.path.append(os.path.dirname(filepath))
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log.debug(f"Attempting to import {modpath}@{filepath}")
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mod = importlib.import_module(modpath)
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self._mods[modpath] = mod
|
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if modpath == '__main__':
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self._mods['__mp_main__'] = mod
|
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except ModuleNotFoundError:
|
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# it is expected the corresponding `ModuleNotExposed` error
|
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# will be raised later
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log.error(f"Failed to import {modpath} in {self.name}")
|
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raise
|
|
|
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def _get_rpc_func(self, ns, funcname):
|
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try:
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return getattr(self._mods[ns], funcname)
|
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except KeyError as err:
|
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mne = ModuleNotExposed(*err.args)
|
|
|
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if ns == '__main__':
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msg = (
|
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"\n\nMake sure you exposed the current module using:\n\n"
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"ActorNursery.start_actor(<name>, enable_modules="
|
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"[__name__])"
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)
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mne.msg += msg
|
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raise mne
|
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|
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async def _stream_handler(
|
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|
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self,
|
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stream: trio.SocketStream,
|
|
|
|
) -> None:
|
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"""Entry point for new inbound connections to the channel server.
|
|
|
|
"""
|
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self._no_more_peers = trio.Event() # unset
|
|
|
|
chan = Channel(stream=stream)
|
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log.runtime(f"New connection to us {chan}")
|
|
|
|
# send/receive initial handshake response
|
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try:
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uid = await self._do_handshake(chan)
|
|
|
|
except (
|
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# trio.BrokenResourceError,
|
|
# trio.ClosedResourceError,
|
|
TransportClosed,
|
|
):
|
|
# XXX: This may propagate up from ``Channel._aiter_recv()``
|
|
# and ``MsgpackStream._inter_packets()`` on a read from the
|
|
# stream particularly when the runtime is first starting up
|
|
# inside ``open_root_actor()`` where there is a check for
|
|
# a bound listener on the "arbiter" addr. the reset will be
|
|
# because the handshake was never meant took place.
|
|
log.warning(f"Channel {chan} failed to handshake")
|
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return
|
|
|
|
# channel tracking
|
|
event = self._peer_connected.pop(uid, None)
|
|
if event:
|
|
# Instructing connection: this is likely a new channel to
|
|
# a recently spawned actor which we'd like to control via
|
|
# async-rpc calls.
|
|
log.debug(f"Waking channel waiters {event.statistics()}")
|
|
# Alert any task waiting on this connection to come up
|
|
event.set()
|
|
|
|
chans = self._peers[uid]
|
|
|
|
# TODO: re-use channels for new connections instead
|
|
# of always new ones; will require changing all the
|
|
# discovery funcs
|
|
if chans:
|
|
log.runtime(
|
|
f"already have channel(s) for {uid}:{chans}?"
|
|
)
|
|
|
|
log.runtime(f"Registered {chan} for {uid}") # type: ignore
|
|
# append new channel
|
|
self._peers[uid].append(chan)
|
|
|
|
# Begin channel management - respond to remote requests and
|
|
# process received reponses.
|
|
try:
|
|
await self._process_messages(chan)
|
|
finally:
|
|
|
|
# channel cleanup sequence
|
|
|
|
# for (channel, cid) in self._rpc_tasks.copy():
|
|
# if channel is chan:
|
|
# with trio.CancelScope(shield=True):
|
|
# await self._cancel_task(cid, channel)
|
|
|
|
# # close all consumer side task mem chans
|
|
# send_chan, _ = self._cids2qs[(chan.uid, cid)]
|
|
# assert send_chan.cid == cid # type: ignore
|
|
# await send_chan.aclose()
|
|
|
|
# Drop ref to channel so it can be gc-ed and disconnected
|
|
log.debug(f"Releasing channel {chan} from {chan.uid}")
|
|
chans = self._peers.get(chan.uid)
|
|
chans.remove(chan)
|
|
|
|
if not chans:
|
|
log.debug(f"No more channels for {chan.uid}")
|
|
self._peers.pop(chan.uid, None)
|
|
|
|
log.debug(f"Peers is {self._peers}")
|
|
|
|
if not self._peers: # no more channels connected
|
|
self._no_more_peers.set()
|
|
log.debug("Signalling no more peer channels")
|
|
|
|
# # XXX: is this necessary (GC should do it?)
|
|
if chan.connected():
|
|
# if the channel is still connected it may mean the far
|
|
# end has not closed and we may have gotten here due to
|
|
# an error and so we should at least try to terminate
|
|
# the channel from this end gracefully.
|
|
|
|
log.debug(f"Disconnecting channel {chan}")
|
|
try:
|
|
# send a msg loop terminate sentinel
|
|
await chan.send(None)
|
|
|
|
# XXX: do we want this?
|
|
# causes "[104] connection reset by peer" on other end
|
|
# await chan.aclose()
|
|
|
|
except trio.BrokenResourceError:
|
|
log.warning(f"Channel for {chan.uid} was already closed")
|
|
|
|
async def _push_result(
|
|
self,
|
|
chan: Channel,
|
|
cid: str,
|
|
msg: Dict[str, Any],
|
|
) -> None:
|
|
"""Push an RPC result to the local consumer's queue.
|
|
"""
|
|
# actorid = chan.uid
|
|
assert chan.uid, f"`chan.uid` can't be {chan.uid}"
|
|
send_chan, recv_chan = self._cids2qs[(chan.uid, cid)]
|
|
assert send_chan.cid == cid # type: ignore
|
|
|
|
# if 'error' in msg:
|
|
# ctx = getattr(recv_chan, '_ctx', None)
|
|
# if ctx:
|
|
# ctx._error_from_remote_msg(msg)
|
|
|
|
# log.debug(f"{send_chan} was terminated at remote end")
|
|
# # indicate to consumer that far end has stopped
|
|
# return await send_chan.aclose()
|
|
|
|
try:
|
|
log.debug(f"Delivering {msg} from {chan.uid} to caller {cid}")
|
|
# maintain backpressure
|
|
await send_chan.send(msg)
|
|
|
|
except trio.BrokenResourceError:
|
|
# TODO: what is the right way to handle the case where the
|
|
# local task has already sent a 'stop' / StopAsyncInteration
|
|
# to the other side but and possibly has closed the local
|
|
# feeder mem chan? Do we wait for some kind of ack or just
|
|
# let this fail silently and bubble up (currently)?
|
|
|
|
# XXX: local consumer has closed their side
|
|
# so cancel the far end streaming task
|
|
log.warning(f"{send_chan} consumer is already closed")
|
|
|
|
def get_memchans(
|
|
self,
|
|
actorid: Tuple[str, str],
|
|
cid: str
|
|
|
|
) -> Tuple[trio.abc.SendChannel, trio.abc.ReceiveChannel]:
|
|
|
|
log.debug(f"Getting result queue for {actorid} cid {cid}")
|
|
try:
|
|
send_chan, recv_chan = self._cids2qs[(actorid, cid)]
|
|
except KeyError:
|
|
send_chan, recv_chan = trio.open_memory_channel(1000)
|
|
send_chan.cid = cid # type: ignore
|
|
recv_chan.cid = cid # type: ignore
|
|
self._cids2qs[(actorid, cid)] = send_chan, recv_chan
|
|
|
|
return send_chan, recv_chan
|
|
|
|
async def send_cmd(
|
|
self,
|
|
chan: Channel,
|
|
ns: str,
|
|
func: str,
|
|
kwargs: dict
|
|
) -> Tuple[str, trio.abc.ReceiveChannel]:
|
|
"""Send a ``'cmd'`` message to a remote actor and return a
|
|
caller id and a ``trio.Queue`` that can be used to wait for
|
|
responses delivered by the local message processing loop.
|
|
"""
|
|
cid = str(uuid.uuid4())
|
|
assert chan.uid
|
|
send_chan, recv_chan = self.get_memchans(chan.uid, cid)
|
|
log.debug(f"Sending cmd to {chan.uid}: {ns}.{func}({kwargs})")
|
|
await chan.send({'cmd': (ns, func, kwargs, self.uid, cid)})
|
|
return cid, recv_chan
|
|
|
|
async def _process_messages(
|
|
self,
|
|
chan: Channel,
|
|
shield: bool = False,
|
|
task_status: TaskStatus[trio.CancelScope] = trio.TASK_STATUS_IGNORED,
|
|
) -> None:
|
|
"""Process messages for the channel async-RPC style.
|
|
|
|
Receive multiplexed RPC requests and deliver responses over ``chan``.
|
|
"""
|
|
# TODO: once https://github.com/python-trio/trio/issues/467 gets
|
|
# worked out we'll likely want to use that!
|
|
msg = None
|
|
log.debug(f"Entering msg loop for {chan} from {chan.uid}")
|
|
try:
|
|
with trio.CancelScope(shield=shield) as loop_cs:
|
|
# this internal scope allows for keeping this message
|
|
# loop running despite the current task having been
|
|
# cancelled (eg. `open_portal()` may call this method from
|
|
# a locally spawned task) and recieve this scope using
|
|
# ``scope = Nursery.start()``
|
|
task_status.started(loop_cs)
|
|
async for msg in chan:
|
|
if msg is None: # loop terminate sentinel
|
|
|
|
log.debug(
|
|
f"Cancelling all tasks for {chan} from {chan.uid}")
|
|
|
|
for (channel, cid) in self._rpc_tasks.copy():
|
|
if channel is chan:
|
|
await self._cancel_task(cid, channel)
|
|
|
|
log.debug(
|
|
f"Msg loop signalled to terminate for"
|
|
f" {chan} from {chan.uid}")
|
|
|
|
break
|
|
|
|
log.transport( # type: ignore
|
|
f"Received msg {msg} from {chan.uid}")
|
|
|
|
cid = msg.get('cid')
|
|
if cid:
|
|
# deliver response to local caller/waiter
|
|
await self._push_result(chan, cid, msg)
|
|
|
|
log.debug(
|
|
f"Waiting on next msg for {chan} from {chan.uid}")
|
|
continue
|
|
|
|
# process command request
|
|
try:
|
|
ns, funcname, kwargs, actorid, cid = msg['cmd']
|
|
except KeyError:
|
|
# This is the non-rpc error case, that is, an
|
|
# error **not** raised inside a call to ``_invoke()``
|
|
# (i.e. no cid was provided in the msg - see above).
|
|
# Push this error to all local channel consumers
|
|
# (normally portals) by marking the channel as errored
|
|
assert chan.uid
|
|
exc = unpack_error(msg, chan=chan)
|
|
chan._exc = exc
|
|
raise exc
|
|
|
|
log.debug(
|
|
f"Processing request from {actorid}\n"
|
|
f"{ns}.{funcname}({kwargs})")
|
|
if ns == 'self':
|
|
func = getattr(self, funcname)
|
|
if funcname == '_cancel_task':
|
|
# XXX: a special case is made here for
|
|
# remote calls since we don't want the
|
|
# remote actor have to know which channel
|
|
# the task is associated with and we can't
|
|
# pass non-primitive types between actors.
|
|
# This means you can use:
|
|
# Portal.run('self', '_cancel_task, cid=did)
|
|
# without passing the `chan` arg.
|
|
kwargs['chan'] = chan
|
|
else:
|
|
# complain to client about restricted modules
|
|
try:
|
|
func = self._get_rpc_func(ns, funcname)
|
|
except (ModuleNotExposed, AttributeError) as err:
|
|
err_msg = pack_error(err)
|
|
err_msg['cid'] = cid
|
|
await chan.send(err_msg)
|
|
continue
|
|
|
|
# spin up a task for the requested function
|
|
log.debug(f"Spawning task for {func}")
|
|
assert self._service_n
|
|
cs = await self._service_n.start(
|
|
partial(_invoke, self, cid, chan, func, kwargs),
|
|
name=funcname,
|
|
)
|
|
# never allow cancelling cancel requests (results in
|
|
# deadlock and other weird behaviour)
|
|
if func != self.cancel:
|
|
if isinstance(cs, Exception):
|
|
log.warning(
|
|
f"Task for RPC func {func} failed with"
|
|
f"{cs}")
|
|
else:
|
|
# mark that we have ongoing rpc tasks
|
|
self._ongoing_rpc_tasks = trio.Event()
|
|
log.runtime(f"RPC func is {func}")
|
|
# store cancel scope such that the rpc task can be
|
|
# cancelled gracefully if requested
|
|
self._rpc_tasks[(chan, cid)] = (
|
|
cs, func, trio.Event())
|
|
else:
|
|
# self.cancel() was called so kill this msg loop
|
|
# and break out into ``_async_main()``
|
|
log.warning(
|
|
f"Actor {self.uid} was remotely cancelled; "
|
|
"waiting on cancellation completion..")
|
|
await self._cancel_complete.wait()
|
|
loop_cs.cancel()
|
|
break
|
|
|
|
log.debug(
|
|
f"Waiting on next msg for {chan} from {chan.uid}")
|
|
else:
|
|
# channel disconnect
|
|
log.debug(
|
|
f"{chan} for {chan.uid} disconnected, cancelling tasks"
|
|
)
|
|
await self.cancel_rpc_tasks(chan)
|
|
|
|
except (
|
|
TransportClosed,
|
|
):
|
|
# channels "breaking" (for TCP streams by EOF or 104
|
|
# connection-reset) is ok since we don't have a teardown
|
|
# handshake for them (yet) and instead we simply bail out of
|
|
# the message loop and expect the teardown sequence to clean
|
|
# up.
|
|
log.debug(f'channel from {chan.uid} closed abruptly:\n{chan}')
|
|
|
|
except (Exception, trio.MultiError) as err:
|
|
|
|
# ship any "internal" exception (i.e. one from internal machinery
|
|
# not from an rpc task) to parent
|
|
log.exception("Actor errored:")
|
|
if self._parent_chan:
|
|
await self._parent_chan.send(pack_error(err))
|
|
|
|
# if this is the `MainProcess` we expect the error broadcasting
|
|
# above to trigger an error at consuming portal "checkpoints"
|
|
raise
|
|
|
|
except trio.Cancelled:
|
|
# debugging only
|
|
log.debug(f"Msg loop was cancelled for {chan}")
|
|
raise
|
|
|
|
finally:
|
|
# msg debugging for when he machinery is brokey
|
|
log.debug(
|
|
f"Exiting msg loop for {chan} from {chan.uid} "
|
|
f"with last msg:\n{msg}")
|
|
|
|
async def _from_parent(
|
|
self,
|
|
parent_addr: Optional[Tuple[str, int]],
|
|
) -> Tuple[Channel, Optional[Tuple[str, int]]]:
|
|
try:
|
|
# Connect back to the parent actor and conduct initial
|
|
# handshake. From this point on if we error, we
|
|
# attempt to ship the exception back to the parent.
|
|
chan = Channel(
|
|
destaddr=parent_addr,
|
|
)
|
|
await chan.connect()
|
|
|
|
# Initial handshake: swap names.
|
|
await self._do_handshake(chan)
|
|
|
|
accept_addr: Optional[Tuple[str, int]] = None
|
|
|
|
if self._spawn_method == "trio":
|
|
# Receive runtime state from our parent
|
|
parent_data = await chan.recv()
|
|
log.debug(
|
|
"Received state from parent:\n"
|
|
f"{parent_data}"
|
|
)
|
|
accept_addr = (
|
|
parent_data.pop('bind_host'),
|
|
parent_data.pop('bind_port'),
|
|
)
|
|
rvs = parent_data.pop('_runtime_vars')
|
|
log.debug(f"Runtime vars are: {rvs}")
|
|
rvs['_is_root'] = False
|
|
_state._runtime_vars.update(rvs)
|
|
|
|
for attr, value in parent_data.items():
|
|
setattr(self, attr, value)
|
|
|
|
return chan, accept_addr
|
|
|
|
except OSError: # failed to connect
|
|
log.warning(
|
|
f"Failed to connect to parent @ {parent_addr},"
|
|
" closing server")
|
|
await self.cancel()
|
|
raise
|
|
|
|
async def _async_main(
|
|
self,
|
|
accept_addr: Optional[Tuple[str, int]] = None,
|
|
# XXX: currently ``parent_addr`` is only needed for the
|
|
# ``multiprocessing`` backend (which pickles state sent to
|
|
# the child instead of relaying it over the connect-back
|
|
# channel). Once that backend is removed we can likely just
|
|
# change this so a simple ``is_subactor: bool`` which will
|
|
# be False when running as root actor and True when as
|
|
# a subactor.
|
|
parent_addr: Optional[Tuple[str, int]] = None,
|
|
task_status: TaskStatus[None] = trio.TASK_STATUS_IGNORED,
|
|
) -> None:
|
|
"""Start the channel server, maybe connect back to the parent, and
|
|
start the main task.
|
|
|
|
A "root-most" (or "top-level") nursery for this actor is opened here
|
|
and when cancelled effectively cancels the actor.
|
|
"""
|
|
registered_with_arbiter = False
|
|
try:
|
|
|
|
# establish primary connection with immediate parent
|
|
self._parent_chan = None
|
|
if parent_addr is not None:
|
|
self._parent_chan, accept_addr_rent = await self._from_parent(
|
|
parent_addr)
|
|
|
|
# either it's passed in because we're not a child
|
|
# or because we're running in mp mode
|
|
if accept_addr_rent is not None:
|
|
accept_addr = accept_addr_rent
|
|
|
|
# load exposed/allowed RPC modules
|
|
# XXX: do this **after** establishing a channel to the parent
|
|
# but **before** starting the message loop for that channel
|
|
# such that import errors are properly propagated upwards
|
|
self.load_modules()
|
|
|
|
# The "root" nursery ensures the channel with the immediate
|
|
# parent is kept alive as a resilient service until
|
|
# cancellation steps have (mostly) occurred in
|
|
# a deterministic way.
|
|
async with trio.open_nursery() as root_nursery:
|
|
self._root_n = root_nursery
|
|
assert self._root_n
|
|
|
|
async with trio.open_nursery() as service_nursery:
|
|
# This nursery is used to handle all inbound
|
|
# connections to us such that if the TCP server
|
|
# is killed, connections can continue to process
|
|
# in the background until this nursery is cancelled.
|
|
self._service_n = service_nursery
|
|
assert self._service_n
|
|
|
|
# Startup up the channel server with,
|
|
# - subactor: the bind address is sent by our parent
|
|
# over our established channel
|
|
# - root actor: the ``accept_addr`` passed to this method
|
|
assert accept_addr
|
|
host, port = accept_addr
|
|
|
|
self._server_n = await service_nursery.start(
|
|
partial(
|
|
self._serve_forever,
|
|
service_nursery,
|
|
accept_host=host,
|
|
accept_port=port
|
|
)
|
|
)
|
|
accept_addr = self.accept_addr
|
|
if _state._runtime_vars['_is_root']:
|
|
_state._runtime_vars['_root_mailbox'] = accept_addr
|
|
|
|
# Register with the arbiter if we're told its addr
|
|
log.debug(f"Registering {self} for role `{self.name}`")
|
|
assert isinstance(self._arb_addr, tuple)
|
|
|
|
async with get_arbiter(*self._arb_addr) as arb_portal:
|
|
await arb_portal.run_from_ns(
|
|
'self',
|
|
'register_actor',
|
|
uid=self.uid,
|
|
sockaddr=accept_addr,
|
|
)
|
|
|
|
registered_with_arbiter = True
|
|
|
|
# init steps complete
|
|
task_status.started()
|
|
|
|
# Begin handling our new connection back to our
|
|
# parent. This is done last since we don't want to
|
|
# start processing parent requests until our channel
|
|
# server is 100% up and running.
|
|
if self._parent_chan:
|
|
await root_nursery.start(
|
|
partial(
|
|
self._process_messages,
|
|
self._parent_chan,
|
|
shield=True,
|
|
)
|
|
)
|
|
log.info("Waiting on service nursery to complete")
|
|
log.info("Service nursery complete")
|
|
log.info("Waiting on root nursery to complete")
|
|
|
|
# Blocks here as expected until the root nursery is
|
|
# killed (i.e. this actor is cancelled or signalled by the parent)
|
|
except Exception as err:
|
|
if not registered_with_arbiter:
|
|
# TODO: I guess we could try to connect back
|
|
# to the parent through a channel and engage a debugger
|
|
# once we have that all working with std streams locking?
|
|
log.exception(
|
|
f"Actor errored and failed to register with arbiter "
|
|
f"@ {self._arb_addr}?")
|
|
log.error(
|
|
"\n\n\t^^^ THIS IS PROBABLY A TRACTOR BUGGGGG!!! ^^^\n"
|
|
"\tCALMLY CALL THE AUTHORITIES AND HIDE YOUR CHILDREN.\n\n"
|
|
"\tYOUR PARENT CODE IS GOING TO KEEP WORKING FINE!!!\n"
|
|
"\tTHIS IS HOW RELIABlE SYSTEMS ARE SUPPOSED TO WORK!?!?\n"
|
|
)
|
|
|
|
if self._parent_chan:
|
|
with trio.CancelScope(shield=True):
|
|
try:
|
|
# internal error so ship to parent without cid
|
|
await self._parent_chan.send(pack_error(err))
|
|
except trio.ClosedResourceError:
|
|
log.error(
|
|
f"Failed to ship error to parent "
|
|
f"{self._parent_chan.uid}, channel was closed")
|
|
|
|
# always!
|
|
log.exception("Actor errored:")
|
|
raise
|
|
|
|
finally:
|
|
log.info("Root nursery complete")
|
|
|
|
# tear down all lifetime contexts if not in guest mode
|
|
# XXX: should this just be in the entrypoint?
|
|
log.warning("Closing all actor lifetime contexts")
|
|
_lifetime_stack.close()
|
|
|
|
# Unregister actor from the arbiter
|
|
if registered_with_arbiter and (
|
|
self._arb_addr is not None
|
|
):
|
|
failed = False
|
|
with trio.move_on_after(0.5) as cs:
|
|
cs.shield = True
|
|
try:
|
|
async with get_arbiter(*self._arb_addr) as arb_portal:
|
|
await arb_portal.run_from_ns(
|
|
'self',
|
|
'unregister_actor',
|
|
uid=self.uid
|
|
)
|
|
except OSError:
|
|
failed = True
|
|
if cs.cancelled_caught:
|
|
failed = True
|
|
if failed:
|
|
log.warning(
|
|
f"Failed to unregister {self.name} from arbiter")
|
|
|
|
# Ensure all peers (actors connected to us as clients) are finished
|
|
if not self._no_more_peers.is_set():
|
|
if any(
|
|
chan.connected() for chan in chain(*self._peers.values())
|
|
):
|
|
log.debug(
|
|
f"Waiting for remaining peers {self._peers} to clear")
|
|
with trio.CancelScope(shield=True):
|
|
await self._no_more_peers.wait()
|
|
log.debug("All peer channels are complete")
|
|
|
|
log.debug("Runtime completed")
|
|
|
|
async def _serve_forever(
|
|
self,
|
|
handler_nursery: trio.Nursery,
|
|
*,
|
|
# (host, port) to bind for channel server
|
|
accept_host: Tuple[str, int] = None,
|
|
accept_port: int = 0,
|
|
task_status: TaskStatus[trio.Nursery] = trio.TASK_STATUS_IGNORED,
|
|
) -> None:
|
|
"""Start the channel server, begin listening for new connections.
|
|
|
|
This will cause an actor to continue living (blocking) until
|
|
``cancel_server()`` is called.
|
|
"""
|
|
self._server_down = trio.Event()
|
|
try:
|
|
async with trio.open_nursery() as server_n:
|
|
l: List[trio.abc.Listener] = await server_n.start(
|
|
partial(
|
|
trio.serve_tcp,
|
|
self._stream_handler,
|
|
# new connections will stay alive even if this server
|
|
# is cancelled
|
|
handler_nursery=handler_nursery,
|
|
port=accept_port,
|
|
host=accept_host,
|
|
)
|
|
)
|
|
log.debug(
|
|
"Started tcp server(s) on"
|
|
f" {[getattr(l, 'socket', 'unknown socket') for l in l]}")
|
|
self._listeners.extend(l)
|
|
task_status.started(server_n)
|
|
finally:
|
|
# signal the server is down since nursery above terminated
|
|
self._server_down.set()
|
|
|
|
def cancel_soon(self) -> None:
|
|
"""Cancel this actor asap; can be called from a sync context.
|
|
|
|
Schedules `.cancel()` to be run immediately just like when
|
|
cancelled by the parent.
|
|
"""
|
|
assert self._service_n
|
|
self._service_n.start_soon(self.cancel)
|
|
|
|
async def cancel(self) -> bool:
|
|
"""Cancel this actor.
|
|
|
|
The "deterministic" teardown sequence in order is:
|
|
- cancel all ongoing rpc tasks by cancel scope
|
|
- cancel the channel server to prevent new inbound
|
|
connections
|
|
- cancel the "service" nursery reponsible for
|
|
spawning new rpc tasks
|
|
- return control the parent channel message loop
|
|
"""
|
|
log.warning(f"{self.uid} is trying to cancel")
|
|
self._cancel_called = True
|
|
|
|
# cancel all ongoing rpc tasks
|
|
with trio.CancelScope(shield=True):
|
|
|
|
# kill any debugger request task to avoid deadlock
|
|
# with the root actor in this tree
|
|
dbcs = _debug._debugger_request_cs
|
|
if dbcs is not None:
|
|
log.debug("Cancelling active debugger request")
|
|
dbcs.cancel()
|
|
|
|
# kill all ongoing tasks
|
|
await self.cancel_rpc_tasks()
|
|
|
|
# stop channel server
|
|
self.cancel_server()
|
|
await self._server_down.wait()
|
|
|
|
# cancel all rpc tasks permanently
|
|
if self._service_n:
|
|
self._service_n.cancel_scope.cancel()
|
|
|
|
log.warning(f"{self.uid} was sucessfullly cancelled")
|
|
self._cancel_complete.set()
|
|
return True
|
|
|
|
# XXX: hard kill logic if needed?
|
|
# def _hard_mofo_kill(self):
|
|
# # If we're the root actor or zombied kill everything
|
|
# if self._parent_chan is None: # TODO: more robust check
|
|
# root = trio.lowlevel.current_root_task()
|
|
# for n in root.child_nurseries:
|
|
# n.cancel_scope.cancel()
|
|
|
|
async def _cancel_task(self, cid, chan):
|
|
"""Cancel a local task by call-id / channel.
|
|
|
|
Note this method will be treated as a streaming function
|
|
by remote actor-callers due to the declaration of ``ctx``
|
|
in the signature (for now).
|
|
"""
|
|
# right now this is only implicitly called by
|
|
# streaming IPC but it should be called
|
|
# to cancel any remotely spawned task
|
|
try:
|
|
# this ctx based lookup ensures the requested task to
|
|
# be cancelled was indeed spawned by a request from this channel
|
|
scope, func, is_complete = self._rpc_tasks[(chan, cid)]
|
|
except KeyError:
|
|
log.warning(f"{cid} has already completed/terminated?")
|
|
return
|
|
|
|
log.debug(
|
|
f"Cancelling task:\ncid: {cid}\nfunc: {func}\n"
|
|
f"peer: {chan.uid}\n")
|
|
|
|
# don't allow cancelling this function mid-execution
|
|
# (is this necessary?)
|
|
if func is self._cancel_task:
|
|
return
|
|
|
|
scope.cancel()
|
|
|
|
# wait for _invoke to mark the task complete
|
|
log.debug(
|
|
f"Waiting on task to cancel:\ncid: {cid}\nfunc: {func}\n"
|
|
f"peer: {chan.uid}\n")
|
|
await is_complete.wait()
|
|
|
|
log.debug(
|
|
f"Sucessfully cancelled task:\ncid: {cid}\nfunc: {func}\n"
|
|
f"peer: {chan.uid}\n")
|
|
|
|
async def cancel_rpc_tasks(
|
|
self,
|
|
only_chan: Optional[Channel] = None,
|
|
) -> None:
|
|
"""Cancel all existing RPC responder tasks using the cancel scope
|
|
registered for each.
|
|
"""
|
|
tasks = self._rpc_tasks
|
|
log.info(f"Cancelling all {len(tasks)} rpc tasks:\n{tasks} ")
|
|
for (chan, cid) in tasks.copy():
|
|
if only_chan is not None:
|
|
if only_chan != chan:
|
|
continue
|
|
|
|
# TODO: this should really done in a nursery batch
|
|
await self._cancel_task(cid, chan)
|
|
|
|
log.info(
|
|
f"Waiting for remaining rpc tasks to complete {tasks}")
|
|
await self._ongoing_rpc_tasks.wait()
|
|
|
|
def cancel_server(self) -> None:
|
|
"""Cancel the internal channel server nursery thereby
|
|
preventing any new inbound connections from being established.
|
|
"""
|
|
if self._server_n:
|
|
log.debug("Shutting down channel server")
|
|
self._server_n.cancel_scope.cancel()
|
|
|
|
@property
|
|
def accept_addr(self) -> Optional[Tuple[str, int]]:
|
|
"""Primary address to which the channel server is bound.
|
|
"""
|
|
# throws OSError on failure
|
|
return self._listeners[0].socket.getsockname() # type: ignore
|
|
|
|
def get_parent(self) -> Portal:
|
|
"""Return a portal to our parent actor."""
|
|
assert self._parent_chan, "No parent channel for this actor?"
|
|
return Portal(self._parent_chan)
|
|
|
|
def get_chans(self, uid: Tuple[str, str]) -> List[Channel]:
|
|
"""Return all channels to the actor with provided uid."""
|
|
return self._peers[uid]
|
|
|
|
async def _do_handshake(
|
|
self,
|
|
chan: Channel
|
|
) -> Tuple[str, str]:
|
|
"""Exchange (name, UUIDs) identifiers as the first communication step.
|
|
|
|
These are essentially the "mailbox addresses" found in actor model
|
|
parlance.
|
|
"""
|
|
await chan.send(self.uid)
|
|
uid: Tuple[str, str] = await chan.recv()
|
|
|
|
if not isinstance(uid, tuple):
|
|
raise ValueError(f"{uid} is not a valid uid?!")
|
|
|
|
chan.uid = uid
|
|
log.runtime(f"Handshake with actor {uid}@{chan.raddr} complete")
|
|
return uid
|
|
|
|
|
|
class Arbiter(Actor):
|
|
"""A special actor who knows all the other actors and always has
|
|
access to a top level nursery.
|
|
|
|
The arbiter is by default the first actor spawned on each host
|
|
and is responsible for keeping track of all other actors for
|
|
coordination purposes. If a new main process is launched and an
|
|
arbiter is already running that arbiter will be used.
|
|
"""
|
|
is_arbiter = True
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
self._registry = defaultdict(list)
|
|
self._waiters = {}
|
|
super().__init__(*args, **kwargs)
|
|
|
|
async def find_actor(self, name: str) -> Optional[Tuple[str, int]]:
|
|
for uid, sockaddr in self._registry.items():
|
|
if name in uid:
|
|
return sockaddr
|
|
|
|
return None
|
|
|
|
async def get_registry(
|
|
self
|
|
) -> Dict[str, Tuple[str, str]]:
|
|
"""Return current name registry.
|
|
"""
|
|
# NOTE: requires ``strict_map_key=False`` to the msgpack
|
|
# unpacker since we have tuples as keys (not this makes the
|
|
# arbiter suscetible to hashdos):
|
|
# https://github.com/msgpack/msgpack-python#major-breaking-changes-in-msgpack-10
|
|
return self._registry
|
|
|
|
async def wait_for_actor(
|
|
self, name: str
|
|
) -> List[Tuple[str, int]]:
|
|
"""Wait for a particular actor to register.
|
|
|
|
This is a blocking call if no actor by the provided name is currently
|
|
registered.
|
|
"""
|
|
sockaddrs = []
|
|
|
|
for (aname, _), sockaddr in self._registry.items():
|
|
if name == aname:
|
|
sockaddrs.append(sockaddr)
|
|
|
|
if not sockaddrs:
|
|
waiter = trio.Event()
|
|
self._waiters.setdefault(name, []).append(waiter)
|
|
await waiter.wait()
|
|
for uid in self._waiters[name]:
|
|
sockaddrs.append(self._registry[uid])
|
|
|
|
return sockaddrs
|
|
|
|
async def register_actor(
|
|
self, uid: Tuple[str, str], sockaddr: Tuple[str, int]
|
|
) -> None:
|
|
name, uuid = uid
|
|
self._registry[uid] = sockaddr
|
|
|
|
# pop and signal all waiter events
|
|
events = self._waiters.pop(name, ())
|
|
self._waiters.setdefault(name, []).append(uid)
|
|
for event in events:
|
|
if isinstance(event, trio.Event):
|
|
event.set()
|
|
|
|
async def unregister_actor(self, uid: Tuple[str, str]) -> None:
|
|
self._registry.pop(uid)
|