Drop worker pool and add debug example
Tyler Goodlet
parent
4a512bc879
commit
71a35aadef
166
docs/README.rst
166
docs/README.rst
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@ -71,12 +71,16 @@ Alluring Features
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Example: self-destruct a process tree
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-------------------------------------
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``tractor`` protects you from zombies, no matter what.
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.. code:: python
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"""
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Run with a process monitor from a terminal using:
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$TERM -e watch -n 0.1 "pstree -a $$" & python examples/parallelism/we_are_processes.py && kill $!
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Run with a process monitor from a terminal using::
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$TERM -e watch -n 0.1 "pstree -a $$" \
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& python examples/parallelism/we_are_processes.py \
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&& kill $!
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"""
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from multiprocessing import cpu_count
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@ -115,133 +119,81 @@ Example: self-destruct a process tree
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The example you're probably after...
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------------------------------------
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It seems the initial query from most new users is "how do I make a worker
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It seems the initial ask from most new users is "how do I make a worker
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pool thing?".
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``tractor`` is built to handle any SC process tree you can
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imagine; the "worker pool" pattern is a trivial special case:
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imagine; the "worker pool" pattern is a trivial special case.
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We have a `full re-implementation <concurrent_actors_primes>`_ of the std-lib's
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``concurrent.futures.ProcessPoolExecutor`` example for reference.
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You can run it like so (from this dir) to see the process tree in
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real time::
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$TERM -e watch -n 0.1 "pstree -a $$" \
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& python examples/parallelism/concurrent_actors_primes.py \
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&& kill $!
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This uses no extra threads, fancy semaphores or futures; all we need
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is ``tractor``'s IPC!
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.. _concurrent_actors_primes: https://github.com/goodboy/tractor/blob/readme_pump/examples/parallelism/concurrent_actors_primes.py
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"Native" sub-process debugging
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------------------------------
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Using the magic of `pdb++`_ and some IPC tricks we've
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been able to create a native feeling debugging experience for
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any (sub)-process in your ``tractor`` tree.
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.. code:: python
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"""
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Demonstration of the prime number detector example from the
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``concurrent.futures`` docs:
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https://docs.python.org/3/library/concurrent.futures.html#processpoolexecutor-example
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This uses no extra threads, fancy semaphores or futures; all we need
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is ``tractor``'s channels.
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"""
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from contextlib import asynccontextmanager
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from typing import List, Callable
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import itertools
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import math
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import time
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from os import getpid
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import tractor
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import trio
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from async_generator import aclosing
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PRIMES = [
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112272535095293,
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112582705942171,
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112272535095293,
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115280095190773,
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115797848077099,
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1099726899285419,
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]
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async def breakpoint_forever():
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"Indefinitely re-enter debugger in child actor."
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while True:
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yield 'yo'
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await tractor.breakpoint()
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def is_prime(n):
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if n < 2:
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return False
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if n == 2:
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return True
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if n % 2 == 0:
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return False
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sqrt_n = int(math.floor(math.sqrt(n)))
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for i in range(3, sqrt_n + 1, 2):
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if n % i == 0:
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return False
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return True
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@asynccontextmanager
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async def worker_pool(workers=4):
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"""Though it's a trivial special case for ``tractor``, the well
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known "worker pool" seems to be the defacto "but, I want this
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process pattern!" for most parallelism pilgrims.
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Yes, the workers stay alive (and ready for work) until you close
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the context.
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"""
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async with tractor.open_nursery() as tn:
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portals = []
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snd_chan, recv_chan = trio.open_memory_channel(len(PRIMES))
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for i in range(workers):
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# this starts a new sub-actor (process + trio runtime) and
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# stores it's "portal" for later use to "submit jobs" (ugh).
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portals.append(
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await tn.start_actor(
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f'worker_{i}',
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enable_modules=[__name__],
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)
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)
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async def _map(
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worker_func: Callable[[int], bool],
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sequence: List[int]
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) -> List[bool]:
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# define an async (local) task to collect results from workers
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async def send_result(func, value, portal):
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await snd_chan.send((value, await portal.run(func, n=value)))
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async with trio.open_nursery() as n:
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for value, portal in zip(sequence, itertools.cycle(portals)):
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n.start_soon(
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send_result,
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worker_func,
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value,
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portal
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)
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# deliver results as they arrive
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for _ in range(len(sequence)):
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yield await recv_chan.receive()
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# deliver the parallel "worker mapper" to user code
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yield _map
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# tear down all "workers" on pool close
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await tn.cancel()
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async def name_error():
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"Raise a ``NameError``"
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getattr(doggypants)
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async def main():
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"""Test breakpoint in a streaming actor.
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"""
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async with tractor.open_nursery(
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debug_mode=True,
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loglevel='error',
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) as n:
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async with worker_pool() as actor_map:
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p0 = await n.start_actor('bp_forever', enable_modules=[__name__])
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p1 = await n.start_actor('name_error', enable_modules=[__name__])
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start = time.time()
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async with aclosing(actor_map(is_prime, PRIMES)) as results:
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async for number, prime in results:
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print(f'{number} is prime: {prime}')
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print(f'processing took {time.time() - start} seconds')
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# retreive results
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stream = await p0.run(breakpoint_forever)
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await p1.run(name_error)
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if __name__ == '__main__':
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start = time.time()
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trio.run(main)
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print(f'script took {time.time() - start} seconds')
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You can run this with::
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>>> python examples/debugging/multi_daemon_subactors.py
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And, yes, there's a built-in crash handling mode B)
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We're hoping to add a respawn-from-repl system soon!
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Feel like saying hi?
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