tractor/tractor/__init__.py

130 lines
3.8 KiB
Python

"""
tractor: An actor model micro-framework built on
``trio`` and ``multiprocessing``.
"""
import importlib
from functools import partial
from typing import Tuple, Any
import typing
import trio # type: ignore
from trio import MultiError
from . import log
from ._ipc import _connect_chan, Channel
from ._streaming import Context, stream
from ._discovery import get_arbiter, find_actor, wait_for_actor
from ._actor import Actor, _start_actor, Arbiter
from ._trionics import open_nursery
from ._state import current_actor
from ._exceptions import RemoteActorError, ModuleNotExposed
from . import msg
from . import _spawn
__all__ = [
'current_actor',
'find_actor',
'get_arbiter',
'open_nursery',
'wait_for_actor',
'Channel',
'Context',
'stream',
'MultiError',
'RemoteActorError',
'ModuleNotExposed',
'msg'
]
# set at startup and after forks
_default_arbiter_host = '127.0.0.1'
_default_arbiter_port = 1616
async def _main(
async_fn: typing.Callable[..., typing.Awaitable],
args: Tuple,
kwargs: typing.Dict[str, typing.Any],
name: str,
arbiter_addr: Tuple[str, int]
) -> typing.Any:
"""Async entry point for ``tractor``.
"""
logger = log.get_logger('tractor')
main = partial(async_fn, *args)
arbiter_addr = (host, port) = arbiter_addr or (
_default_arbiter_host, _default_arbiter_port)
loglevel = kwargs.get('loglevel', log.get_loglevel())
if loglevel is not None:
log._default_loglevel = loglevel
log.get_console_log(loglevel)
# make a temporary connection to see if an arbiter exists
arbiter_found = False
try:
async with _connect_chan(host, port):
arbiter_found = True
except OSError:
logger.warning(f"No actor could be found @ {host}:{port}")
# create a local actor and start up its main routine/task
if arbiter_found: # we were able to connect to an arbiter
logger.info(f"Arbiter seems to exist @ {host}:{port}")
actor = Actor(
name or 'anonymous',
arbiter_addr=arbiter_addr,
**kwargs
)
host, port = (host, 0)
else:
# start this local actor as the arbiter
actor = Arbiter(
name or 'arbiter', arbiter_addr=arbiter_addr, **kwargs)
# ``Actor._async_main()`` creates an internal nursery if one is not
# provided and thus blocks here until it's main task completes.
# Note that if the current actor is the arbiter it is desirable
# for it to stay up indefinitely until a re-election process has
# taken place - which is not implemented yet FYI).
return await _start_actor(
actor, main, host, port, arbiter_addr=arbiter_addr)
def run(
async_fn: typing.Callable[..., typing.Awaitable],
*args: Tuple,
name: str = None,
arbiter_addr: Tuple[str, int] = (
_default_arbiter_host, _default_arbiter_port),
# the `multiprocessing` start method:
# https://docs.python.org/3/library/multiprocessing.html#contexts-and-start-methods
start_method: str = 'forkserver',
**kwargs: typing.Dict[str, typing.Any],
) -> Any:
"""Run a trio-actor async function in process.
This is tractor's main entry and the start point for any async actor.
"""
_spawn.try_set_start_method(start_method)
return trio.run(_main, async_fn, args, kwargs, name, arbiter_addr)
def run_daemon(
rpc_module_paths: Tuple[str],
**kwargs
) -> None:
"""Spawn daemon actor which will respond to RPC.
This is a convenience wrapper around
``tractor.run(trio.sleep(float('inf')))`` such that the first actor spawned
is meant to run forever responding to RPC requests.
"""
kwargs['rpc_module_paths'] = rpc_module_paths
for path in rpc_module_paths:
importlib.import_module(path)
return run(partial(trio.sleep, float('inf')), **kwargs)