Files
ray/python/ray/actor.py
T
Chelsea Finn f97d0393cc Fix to json decoding bug (#597)
* fix json decoding bug

* Fix linting error.
2017-05-25 18:48:39 -07:00

397 lines
15 KiB
Python

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import cloudpickle as pickle
import hashlib
import inspect
import json
import numpy as np
import redis
import traceback
import ray.local_scheduler
import ray.signature as signature
import ray.worker
from ray.utils import random_string, binary_to_hex, hex_to_binary
def random_actor_id():
return ray.local_scheduler.ObjectID(random_string())
def random_actor_class_id():
return random_string()
def get_actor_method_function_id(attr):
"""Get the function ID corresponding to an actor method.
Args:
attr (str): The attribute name of the method.
Returns:
Function ID corresponding to the method.
"""
function_id_hash = hashlib.sha1()
function_id_hash.update(attr.encode("ascii"))
function_id = function_id_hash.digest()
assert len(function_id) == 20
return ray.local_scheduler.ObjectID(function_id)
def fetch_and_register_actor(actor_class_key, worker):
"""Import an actor.
This will be called by the worker's import thread when the worker receives
the actor_class export, assuming that the worker is an actor for that class.
"""
actor_id_str = worker.actor_id
(driver_id, class_id, class_name,
module, pickled_class, actor_method_names) = worker.redis_client.hmget(
actor_class_key, ["driver_id", "class_id", "class_name", "module",
"class", "actor_method_names"])
actor_name = class_name.decode("ascii")
module = module.decode("ascii")
actor_method_names = json.loads(actor_method_names.decode("ascii"))
# Create a temporary actor with some temporary methods so that if the actor
# fails to be unpickled, the temporary actor can be used (just to produce
# error messages and to prevent the driver from hanging).
class TemporaryActor(object):
pass
worker.actors[actor_id_str] = TemporaryActor()
def temporary_actor_method(*xs):
raise Exception("The actor with name {} failed to be imported, and so "
"cannot execute this method".format(actor_name))
for actor_method_name in actor_method_names:
function_id = get_actor_method_function_id(actor_method_name).id()
worker.functions[driver_id][function_id] = (actor_method_name,
temporary_actor_method)
try:
unpickled_class = pickle.loads(pickled_class)
except Exception:
# If an exception was thrown when the actor was imported, we record the
# traceback and notify the scheduler of the failure.
traceback_str = ray.worker.format_error_message(traceback.format_exc())
# Log the error message.
worker.push_error_to_driver(driver_id, "register_actor", traceback_str,
data={"actor_id": actor_id_str})
else:
# TODO(pcm): Why is the below line necessary?
unpickled_class.__module__ = module
worker.actors[actor_id_str] = unpickled_class.__new__(unpickled_class)
for (k, v) in inspect.getmembers(
unpickled_class, predicate=(lambda x: (inspect.isfunction(x) or
inspect.ismethod(x)))):
function_id = get_actor_method_function_id(k).id()
worker.functions[driver_id][function_id] = (k, v)
# We do not set worker.function_properties[driver_id][function_id]
# because we currently do need the actor worker to submit new tasks for
# the actor.
def attempt_to_reserve_gpus(num_gpus, driver_id, local_scheduler, worker):
"""Attempt to acquire GPUs on a particular local scheduler for an actor.
Args:
num_gpus: The number of GPUs to acquire.
driver_id: The ID of the driver responsible for creating the actor.
local_scheduler: Information about the local scheduler.
Returns:
True if the GPUs were successfully reserved and false otherwise.
"""
assert num_gpus != 0
local_scheduler_id = local_scheduler["DBClientID"]
local_scheduler_total_gpus = int(local_scheduler["NumGPUs"])
success = False
# Attempt to acquire GPU IDs atomically.
with worker.redis_client.pipeline() as pipe:
while True:
try:
# If this key is changed before the transaction below (the multi/exec
# block), then the transaction will not take place.
pipe.watch(local_scheduler_id)
# Figure out which GPUs are currently in use.
result = worker.redis_client.hget(local_scheduler_id, "gpus_in_use")
gpus_in_use = dict() if result is None else json.loads(
result.decode("ascii"))
num_gpus_in_use = 0
for key in gpus_in_use:
num_gpus_in_use += gpus_in_use[key]
assert num_gpus_in_use <= local_scheduler_total_gpus
pipe.multi()
if local_scheduler_total_gpus - num_gpus_in_use >= num_gpus:
# There are enough available GPUs, so try to reserve some. We use the
# hex driver ID in hex as a dictionary key so that the dictionary is
# JSON serializable.
driver_id_hex = binary_to_hex(driver_id)
if driver_id_hex not in gpus_in_use:
gpus_in_use[driver_id_hex] = 0
gpus_in_use[driver_id_hex] += num_gpus
# Stick the updated GPU IDs back in Redis
pipe.hset(local_scheduler_id, "gpus_in_use", json.dumps(gpus_in_use))
success = True
pipe.execute()
# If a WatchError is not raised, then the operations should have gone
# through atomically.
break
except redis.WatchError:
# Another client must have changed the watched key between the time we
# started WATCHing it and the pipeline's execution. We should just
# retry.
success = False
continue
return success
def select_local_scheduler(local_schedulers, num_gpus, worker):
"""Select a local scheduler to assign this actor to.
Args:
local_schedulers: A list of dictionaries of information about the local
schedulers.
num_gpus (int): The number of GPUs that must be reserved for this actor.
Returns:
The ID of the local scheduler that has been chosen.
Raises:
Exception: An exception is raised if no local scheduler can be found with
sufficient resources.
"""
driver_id = worker.task_driver_id.id()
local_scheduler_id = None
# Loop through all of the local schedulers in a random order.
local_schedulers = np.random.permutation(local_schedulers)
for local_scheduler in local_schedulers:
if local_scheduler["NumCPUs"] < 1:
continue
if local_scheduler["NumGPUs"] < num_gpus:
continue
if num_gpus == 0:
local_scheduler_id = hex_to_binary(local_scheduler["DBClientID"])
break
else:
# Try to reserve enough GPUs on this local scheduler.
success = attempt_to_reserve_gpus(num_gpus, driver_id, local_scheduler,
worker)
if success:
local_scheduler_id = hex_to_binary(local_scheduler["DBClientID"])
break
if local_scheduler_id is None:
raise Exception("Could not find a node with enough GPUs or other "
"resources to create this actor. The local scheduler "
"information is {}.".format(local_schedulers))
return local_scheduler_id
def export_actor_class(class_id, Class, actor_method_names, worker):
if worker.mode is None:
raise NotImplemented("TODO(pcm): Cache actors")
key = b"ActorClass:" + class_id
d = {"driver_id": worker.task_driver_id.id(),
"class_name": Class.__name__,
"module": Class.__module__,
"class": pickle.dumps(Class),
"actor_method_names": json.dumps(list(actor_method_names))}
worker.redis_client.hmset(key, d)
worker.redis_client.rpush("Exports", key)
def export_actor(actor_id, class_id, actor_method_names, num_cpus, num_gpus,
worker):
"""Export an actor to redis.
Args:
actor_id: The ID of the actor.
actor_method_names (list): A list of the names of this actor's methods.
num_cpus (int): The number of CPUs that this actor requires.
num_gpus (int): The number of GPUs that this actor requires.
"""
ray.worker.check_main_thread()
if worker.mode is None:
raise Exception("Actors cannot be created before Ray has been started. "
"You can start Ray with 'ray.init()'.")
key = "Actor:{}".format(actor_id.id())
# For now, all actor methods have 1 return value.
driver_id = worker.task_driver_id.id()
for actor_method_name in actor_method_names:
# TODO(rkn): When we create a second actor, we are probably overwriting
# the values from the first actor here. This may or may not be a problem.
function_id = get_actor_method_function_id(actor_method_name).id()
worker.function_properties[driver_id][function_id] = (1, num_cpus, 0)
# Get a list of the local schedulers from the client table.
client_table = ray.global_state.client_table()
local_schedulers = []
for ip_address, clients in client_table.items():
for client in clients:
if client["ClientType"] == "local_scheduler" and not client["Deleted"]:
local_schedulers.append(client)
# Select a local scheduler for the actor.
local_scheduler_id = select_local_scheduler(local_schedulers, num_gpus,
worker)
assert local_scheduler_id is not None
# We must put the actor information in Redis before publishing the actor
# notification so that when the newly created actor attempts to fetch the
# information from Redis, it is already there.
worker.redis_client.hmset(key, {"class_id": class_id,
"num_gpus": num_gpus})
# Really we should encode this message as a flatbuffer object. However, we're
# having trouble getting that to work. It almost works, but in Python 2.7,
# builder.CreateString fails on byte strings that contain characters outside
# range(128).
# TODO(rkn): There is actually no guarantee that the local scheduler that we
# are publishing to has already subscribed to the actor_notifications
# channel. Therefore, this message may be missed and the workload will hang.
# This is a bug.
worker.redis_client.publish("actor_notifications",
actor_id.id() + driver_id + local_scheduler_id)
def actor(*args, **kwargs):
raise Exception("The @ray.actor decorator is deprecated. Instead, please "
"use @ray.remote.")
def make_actor(Class, num_cpus, num_gpus):
class_id = random_actor_class_id()
# The list exported will have length 0 if the class has not been exported
# yet, and length one if it has. This is just implementing a bool, but we
# don't use a bool because we need to modify it inside of the NewClass
# constructor.
exported = []
# The function actor_method_call gets called if somebody tries to call a
# method on their local actor stub object.
def actor_method_call(actor_id, attr, function_signature, *args, **kwargs):
ray.worker.check_connected()
ray.worker.check_main_thread()
args = signature.extend_args(function_signature, args, kwargs)
function_id = get_actor_method_function_id(attr)
object_ids = ray.worker.global_worker.submit_task(function_id, "", args,
actor_id=actor_id)
if len(object_ids) == 1:
return object_ids[0]
elif len(object_ids) > 1:
return object_ids
class ActorMethod(object):
def __init__(self, method_name, actor_id, method_signature):
self.method_name = method_name
self.actor_id = actor_id
self.method_signature = method_signature
def __call__(self, *args, **kwargs):
raise Exception("Actor methods cannot be called directly. Instead "
"of running 'object.{}()', try 'object.{}.remote()'."
.format(self.method_name, self.method_name))
def remote(self, *args, **kwargs):
return actor_method_call(self.actor_id, self.method_name,
self.method_signature, *args, **kwargs)
class NewClass(object):
def __init__(self, *args, **kwargs):
raise Exception("Actor classes cannot be instantiated directly. "
"Instead of running '{}()', try '{}.remote()'."
.format(Class.__name__, Class.__name__))
@classmethod
def remote(cls, *args, **kwargs):
actor_object = cls.__new__(cls)
actor_object._manual_init(*args, **kwargs)
return actor_object
def _manual_init(self, *args, **kwargs):
self._ray_actor_id = random_actor_id()
self._ray_actor_methods = {
k: v for (k, v) in inspect.getmembers(
Class, predicate=(lambda x: (inspect.isfunction(x) or
inspect.ismethod(x))))}
# Extract the signatures of each of the methods. This will be used to
# catch some errors if the methods are called with inappropriate
# arguments.
self._ray_method_signatures = dict()
for k, v in self._ray_actor_methods.items():
# Print a warning message if the method signature is not supported.
# We don't raise an exception because if the actor inherits from a
# class that has a method whose signature we don't support, we
# there may not be much the user can do about it.
signature.check_signature_supported(v, warn=True)
self._ray_method_signatures[k] = signature.extract_signature(
v, ignore_first=True)
# Create objects to wrap method invocations. This is done so that we
# can invoke methods with actor.method.remote() instead of
# actor.method().
self._actor_method_invokers = dict()
for k, v in self._ray_actor_methods.items():
self._actor_method_invokers[k] = ActorMethod(
k, self._ray_actor_id, self._ray_method_signatures[k])
# Export the actor class if it has not been exported yet.
if len(exported) == 0:
export_actor_class(class_id, Class, self._ray_actor_methods.keys(),
ray.worker.global_worker)
exported.append(0)
# Export the actor.
export_actor(self._ray_actor_id, class_id,
self._ray_actor_methods.keys(), num_cpus, num_gpus,
ray.worker.global_worker)
# Call __init__ as a remote function.
if "__init__" in self._ray_actor_methods.keys():
actor_method_call(self._ray_actor_id, "__init__",
self._ray_method_signatures["__init__"],
*args, **kwargs)
else:
print("WARNING: this object has no __init__ method.")
# Make tab completion work.
def __dir__(self):
return self._ray_actor_methods
def __getattribute__(self, attr):
# The following is needed so we can still access self.actor_methods.
if attr in ["_manual_init", "_ray_actor_id", "_ray_actor_methods",
"_actor_method_invokers", "_ray_method_signatures"]:
return object.__getattribute__(self, attr)
if attr in self._ray_actor_methods.keys():
return self._actor_method_invokers[attr]
# There is no method with this name, so raise an exception.
raise AttributeError("'{}' Actor object has no attribute '{}'"
.format(Class, attr))
def __repr__(self):
return "Actor(" + self._ray_actor_id.hex() + ")"
def __reduce__(self):
raise Exception("Actor objects cannot be pickled.")
return NewClass
ray.worker.global_worker.fetch_and_register_actor = fetch_and_register_actor
ray.worker.global_worker.make_actor = make_actor