Use pickle by default for serialization (#5978)

This commit is contained in:
Philipp Moritz
2019-11-10 18:12:18 -08:00
committed by GitHub
parent 01aee8d970
commit decaa65cd6
10 changed files with 698 additions and 597 deletions
+17 -457
View File
@@ -8,7 +8,6 @@ import atexit
import faulthandler
import hashlib
import inspect
import io
import json
import logging
import os
@@ -22,8 +21,6 @@ import traceback
import random
# Ray modules
import pyarrow
import pyarrow.plasma as plasma
import ray.cloudpickle as pickle
import ray.gcs_utils
import ray.memory_monitor as memory_monitor
@@ -43,17 +40,11 @@ from ray import (
)
from ray import import_thread
from ray import profiling
from ray._raylet import Pickle5Writer, unpack_pickle5_buffers
from ray.gcs_utils import ErrorType
from ray.exceptions import (
RayActorError,
RayError,
RayTaskError,
RayWorkerError,
ObjectStoreFullError,
UnreconstructableError,
RAY_EXCEPTION_TYPES,
)
from ray.function_manager import FunctionActorManager
from ray.utils import (
@@ -203,7 +194,7 @@ class Worker(object):
if self.actor_init_error is not None:
raise self.actor_init_error
def get_serialization_context(self, job_id):
def get_serialization_context(self, job_id=None):
"""Get the SerializationContext of the job that this worker is processing.
Args:
@@ -213,13 +204,17 @@ class Worker(object):
Returns:
The serialization context of the given job.
"""
# This function needs to be proctected by a lock, because it will be
# This function needs to be protected by a lock, because it will be
# called by`register_class_for_serialization`, as well as the import
# thread, from different threads. Also, this function will recursively
# call itself, so we use RLock here.
if job_id is None:
job_id = self.current_job_id
with self.lock:
if job_id not in self.serialization_context_map:
_initialize_serialization(job_id)
self.serialization_context_map[
job_id] = serialization.SerializationContext(self)
self.serialization_context_map[job_id].initialize()
return self.serialization_context_map[job_id]
def check_connected(self):
@@ -284,199 +279,17 @@ class Worker(object):
"do this, you can wrap the ray.ObjectID in a list and "
"call 'put' on it (or return it).")
if isinstance(value, bytes):
# If the object is a byte array, skip serializing it and
# use a special metadata to indicate it's raw binary. So
# that this object can also be read by Java.
return self.core_worker.put_raw_buffer(value, object_id=object_id)
if self.use_pickle:
return self._serialize_and_put_pickle5(value, object_id=object_id)
else:
return self._serialize_and_put_pyarrow(value, object_id=object_id)
def _serialize_and_put_pickle5(self, value, object_id=None):
"""Serialize an object using pickle5 and store it in the object store.
Args:
value: The value to put in the object store.
object_id: The ID of the object to store. If none, one will be
generated.
Raises:
Exception: An exception is raised if the attempt to store the
object fails. This can happen if the object store is full.
"""
inband, writer = self._serialize_with_pickle5(value)
return self.core_worker.put_pickle5_buffers(
inband, writer, object_id=object_id)
def _serialize_with_pickle5(self, value):
writer = Pickle5Writer()
if ray.cloudpickle.FAST_CLOUDPICKLE_USED:
inband = pickle.dumps(
value, protocol=5, buffer_callback=writer.buffer_callback)
else:
inband = pickle.dumps(value)
return inband, writer
def _serialize_and_put_pyarrow(self, value, object_id=None):
"""Wraps `store_and_register` with cases for existence and pickling.
Args:
object_id (object_id.ObjectID): The object ID of the value to be
put.
value: The value to put in the object store.
"""
serialized_value = self._serialize_with_pyarrow(value)
serialized_value = self.get_serialization_context().serialize(value)
return self.core_worker.put_serialized_object(
serialized_value, object_id=object_id)
def _serialize_with_pyarrow(self, value):
try:
serialized_value = self._store_and_register_pyarrow(value)
except TypeError:
# TypeError can happen because one of the members of the object
# may not be serializable for cloudpickle. So we need
# these extra fallbacks here to start from the beginning.
# Hopefully the object could have a `__reduce__` method.
_register_custom_serializer(type(value), use_pickle=True)
logger.warning("WARNING: Serializing the class {} failed, "
"falling back to cloudpickle.".format(type(value)))
serialized_value = self._store_and_register_pyarrow(value)
return serialized_value
def _store_and_register_pyarrow(self, value, depth=100):
"""Store an object and attempt to register its class if needed.
Args:
value: The value to put in the object store.
depth: The maximum number of classes to recursively register.
Raises:
Exception: An exception is raised if the attempt to serialize the
object fails.
"""
counter = 0
while True:
if counter == depth:
raise Exception("Ray exceeded the maximum number of classes "
"that it will recursively serialize when "
"attempting to serialize an object of "
"type {}.".format(type(value)))
counter += 1
try:
serialization_context = self.get_serialization_context(
self.current_job_id)
return pyarrow.serialize(value, serialization_context)
except pyarrow.SerializationCallbackError as e:
cls_type = type(e.example_object)
try:
_register_custom_serializer(cls_type, use_dict=True)
warning_message = (
"WARNING: Serializing objects of type "
"{} by expanding them as dictionaries "
"of their fields. This behavior may "
"be incorrect in some cases.".format(cls_type))
logger.debug(warning_message)
except (serialization.RayNotDictionarySerializable,
serialization.CloudPickleError,
pickle.pickle.PicklingError, Exception):
# We also handle generic exceptions here because
# cloudpickle can fail with many different types of errors.
warning_message = (
"Falling back to serializing {} objects by using "
"pickle. Use `ray.register_custom_serializer({},...)` "
"to provide faster serialization.".format(
cls_type, cls_type))
try:
_register_custom_serializer(cls_type, use_pickle=True)
logger.warning(warning_message)
except (serialization.CloudPickleError, ValueError):
_register_custom_serializer(
cls_type, use_pickle=True, local=True)
warning_message = ("WARNING: Pickling the class {} "
"failed, so we are using pickle "
"and only registering the class "
"locally.".format(cls_type))
logger.warning(warning_message)
def deserialize_objects(self,
data_metadata_pairs,
object_ids,
error_timeout=10):
assert len(data_metadata_pairs) == len(object_ids)
start_time = time.time()
serialization_context = self.get_serialization_context(
self.current_job_id)
results = []
warning_sent = False
i = 0
while i < len(object_ids):
object_id = object_ids[i]
data, metadata = data_metadata_pairs[i]
try:
results.append(
self._deserialize_object_from_arrow(
data, metadata, object_id, serialization_context))
i += 1
except pyarrow.DeserializationCallbackError:
# Wait a little bit for the import thread to import the class.
# If we currently have the worker lock, we need to release it
# so that the import thread can acquire it.
time.sleep(0.01)
if time.time() - start_time > error_timeout:
warning_message = ("This worker or driver is waiting to "
"receive a class definition so that it "
"can deserialize an object from the "
"object store. This may be fine, or it "
"may be a bug.")
if not warning_sent:
ray.utils.push_error_to_driver(
self,
ray_constants.WAIT_FOR_CLASS_PUSH_ERROR,
warning_message,
job_id=self.current_job_id)
warning_sent = True
return results
def _deserialize_object_from_arrow(self, data, metadata, object_id,
serialization_context):
if metadata:
if metadata == ray_constants.PICKLE5_BUFFER_METADATA:
in_band, buffers = unpack_pickle5_buffers(data)
if len(buffers) > 0:
return pickle.loads(in_band, buffers=buffers)
else:
return pickle.loads(in_band)
# Check if the object should be returned as raw bytes.
if metadata == ray_constants.RAW_BUFFER_METADATA:
if data is None:
return b""
return data.to_pybytes()
# Otherwise, return an exception object based on
# the error type.
error_type = int(metadata)
if error_type == ErrorType.Value("WORKER_DIED"):
return RayWorkerError()
elif error_type == ErrorType.Value("ACTOR_DIED"):
return RayActorError()
elif error_type == ErrorType.Value("OBJECT_UNRECONSTRUCTABLE"):
return UnreconstructableError(ray.ObjectID(object_id.binary()))
else:
assert error_type != ErrorType.Value("OBJECT_IN_PLASMA"), \
"Tried to get object that has been promoted to plasma."
assert False, "Unrecognized error type " + str(error_type)
elif data:
# If data is not empty, deserialize the object.
return pyarrow.deserialize(data, serialization_context)
else:
# Object isn't available in plasma.
return plasma.ObjectNotAvailable
context = self.get_serialization_context()
return context.deserialize_objects(data_metadata_pairs, object_ids,
error_timeout)
def get_objects(self, object_ids):
"""Get the values in the object store associated with the IDs.
@@ -712,98 +525,6 @@ def print_failed_task(task_status):
task_status["error_message"]))
def _initialize_serialization(job_id, worker=global_worker):
"""Initialize the serialization library.
This defines a custom serializer for object IDs and also tells ray to
serialize several exception classes that we define for error handling.
"""
serialization_context = pyarrow.default_serialization_context()
# Tell the serialization context to use the cloudpickle version that we
# ship with Ray.
serialization_context.set_pickle(pickle.dumps, pickle.loads)
pyarrow.register_torch_serialization_handlers(serialization_context)
def id_serializer(obj):
if isinstance(obj, ray.ObjectID) and obj.is_direct_actor_type():
raise NotImplementedError(
"Objects produced by direct actor calls cannot be "
"passed to other tasks as arguments.")
return pickle.dumps(obj)
def id_deserializer(serialized_obj):
return pickle.loads(serialized_obj)
for id_type in ray._raylet._ID_TYPES:
serialization_context.register_type(
id_type,
"{}.{}".format(id_type.__module__, id_type.__name__),
custom_serializer=id_serializer,
custom_deserializer=id_deserializer)
def actor_handle_serializer(obj):
return obj._serialization_helper(True)
def actor_handle_deserializer(serialized_obj):
new_handle = ray.actor.ActorHandle.__new__(ray.actor.ActorHandle)
new_handle._deserialization_helper(serialized_obj, True)
return new_handle
# We register this serializer on each worker instead of calling
# _register_custom_serializer from the driver so that isinstance still
# works.
serialization_context.register_type(
ray.actor.ActorHandle,
"ray.ActorHandle",
pickle=False,
custom_serializer=actor_handle_serializer,
custom_deserializer=actor_handle_deserializer)
worker.serialization_context_map[job_id] = serialization_context
if not worker.use_pickle:
for error_cls in RAY_EXCEPTION_TYPES:
_register_custom_serializer(
error_cls,
use_dict=True,
local=True,
job_id=job_id,
class_id=error_cls.__module__ + ". " + error_cls.__name__,
)
# Tell Ray to serialize lambdas with pickle.
_register_custom_serializer(
type(lambda: 0),
use_pickle=True,
local=True,
job_id=job_id,
class_id="lambda")
# Tell Ray to serialize types with pickle.
_register_custom_serializer(
type(int),
use_pickle=True,
local=True,
job_id=job_id,
class_id="type")
# Tell Ray to serialize RayParameters as dictionaries. This is
# used when passing around actor handles.
_register_custom_serializer(
ray.signature.RayParameter,
use_dict=True,
local=True,
job_id=job_id,
class_id="ray.signature.RayParameter")
# Tell Ray to serialize StringIO with pickle. We do this because
# Ray's default __dict__ serialization is incorrect for this type
# (the object's __dict__ is empty and therefore doesn't
# contain the full state of the object).
_register_custom_serializer(
io.StringIO,
use_pickle=True,
local=True,
job_id=job_id,
class_id="io.StringIO")
def init(address=None,
redis_address=None,
num_cpus=None,
@@ -835,7 +556,7 @@ def init(address=None,
raylet_socket_name=None,
temp_dir=None,
load_code_from_local=False,
use_pickle=False,
use_pickle=ray.cloudpickle.FAST_CLOUDPICKLE_USED,
_internal_config=None):
"""Connect to an existing Ray cluster or start one and connect to it.
@@ -1610,48 +1331,6 @@ def _changeproctitle(title, next_title):
setproctitle.setproctitle(next_title)
def _try_to_compute_deterministic_class_id(cls, depth=5):
"""Attempt to produce a deterministic class ID for a given class.
The goal here is for the class ID to be the same when this is run on
different worker processes. Pickling, loading, and pickling again seems to
produce more consistent results than simply pickling. This is a bit crazy
and could cause problems, in which case we should revert it and figure out
something better.
Args:
cls: The class to produce an ID for.
depth: The number of times to repeatedly try to load and dump the
string while trying to reach a fixed point.
Returns:
A class ID for this class. We attempt to make the class ID the same
when this function is run on different workers, but that is not
guaranteed.
Raises:
Exception: This could raise an exception if cloudpickle raises an
exception.
"""
# Pickling, loading, and pickling again seems to produce more consistent
# results than simply pickling. This is a bit
class_id = pickle.dumps(cls)
for _ in range(depth):
new_class_id = pickle.dumps(pickle.loads(class_id))
if new_class_id == class_id:
# We appear to have reached a fix point, so use this as the ID.
return hashlib.sha1(new_class_id).digest()
class_id = new_class_id
# We have not reached a fixed point, so we may end up with a different
# class ID for this custom class on each worker, which could lead to the
# same class definition being exported many many times.
logger.warning(
"WARNING: Could not produce a deterministic class ID for class "
"{}".format(cls))
return hashlib.sha1(new_class_id).digest()
def register_custom_serializer(cls,
serializer=None,
deserializer=None,
@@ -1664,7 +1343,7 @@ def register_custom_serializer(cls,
The serializer and deserializer are used when transferring objects of
`cls` across processes and nodes. This can be significantly faster than
the Ray default fallbacks. Wraps `_register_custom_serializer` underneath.
the Ray default fallbacks. Wraps `register_custom_serializer` underneath.
`use_pickle` tells Ray to automatically use cloudpickle for serialization,
and `use_dict` automatically uses `cls.__dict__`.
@@ -1697,13 +1376,14 @@ def register_custom_serializer(cls,
raise DeprecationWarning(
"`job_id` is no longer a valid parameter and will be removed in "
"future versions of Ray. If this breaks your application, "
"see `ray.worker._register_custom_serializer`.")
"see `SerializationContext.register_custom_serializer`.")
if local:
raise DeprecationWarning(
"`local` is no longer a valid parameter and will be removed in "
"future versions of Ray. If this breaks your application, "
"see `ray.worker._register_custom_serializer`.")
_register_custom_serializer(
"see `SerializationContext.register_custom_serializer`.")
context = global_worker.get_serialization_context()
context.register_custom_serializer(
cls,
use_pickle=use_pickle,
use_dict=use_dict,
@@ -1712,126 +1392,6 @@ def register_custom_serializer(cls,
class_id=class_id)
def _register_custom_serializer(cls,
use_pickle=False,
use_dict=False,
serializer=None,
deserializer=None,
local=False,
job_id=None,
class_id=None):
"""Enable serialization and deserialization for a particular class.
This method runs the register_class function defined below on every worker,
which will enable ray to properly serialize and deserialize objects of
this class.
Args:
cls (type): The class that ray should use this custom serializer for.
use_pickle (bool): If true, then objects of this class will be
serialized using pickle.
use_dict: If true, then objects of this class be serialized turning
their __dict__ fields into a dictionary. Must be False if
use_pickle is true.
serializer: The custom serializer to use. This should be provided if
and only if use_pickle and use_dict are False.
deserializer: The custom deserializer to use. This should be provided
if and only if use_pickle and use_dict are False.
local: True if the serializers should only be registered on the current
worker. This should usually be False.
job_id: ID of the job that we want to register the class for.
class_id (str): Unique ID of the class. Autogenerated if None.
Raises:
RayNotDictionarySerializable: Raised if use_dict is true and cls cannot
be efficiently serialized by Ray.
ValueError: Raised if ray could not autogenerate a class_id.
"""
worker = global_worker
assert (serializer is None) == (deserializer is None), (
"The serializer/deserializer arguments must both be provided or "
"both not be provided.")
use_custom_serializer = (serializer is not None)
assert use_custom_serializer + use_pickle + use_dict == 1, (
"Exactly one of use_pickle, use_dict, or serializer/deserializer must "
"be specified.")
if worker.use_pickle and serializer is None:
# In this case it should do nothing.
return
if use_dict:
# Raise an exception if cls cannot be serialized efficiently by Ray.
serialization.check_serializable(cls)
if class_id is None:
if not local:
# In this case, the class ID will be used to deduplicate the class
# across workers. Note that cloudpickle unfortunately does not
# produce deterministic strings, so these IDs could be different
# on different workers. We could use something weaker like
# cls.__name__, however that would run the risk of having
# collisions.
# TODO(rkn): We should improve this.
try:
# Attempt to produce a class ID that will be the same on each
# worker. However, determinism is not guaranteed, and the
# result may be different on different workers.
class_id = _try_to_compute_deterministic_class_id(cls)
except Exception:
raise ValueError(
"Failed to use pickle in generating a unique id for '{}'. "
"Provide a unique class_id.".format(cls))
else:
# In this case, the class ID only needs to be meaningful on this
# worker and not across workers.
class_id = _random_string()
# Make sure class_id is a string.
class_id = ray.utils.binary_to_hex(class_id)
if job_id is None:
job_id = worker.current_job_id
assert isinstance(job_id, JobID)
def register_class_for_serialization(worker_info):
if worker_info["worker"].use_pickle:
if pickle.FAST_CLOUDPICKLE_USED:
# construct a reducer
pickle.CloudPickler.dispatch[
cls] = lambda obj: (deserializer, (serializer(obj), ))
else:
def _CloudPicklerReducer(_self, obj):
_self.save_reduce(
deserializer, (serializer(obj), ), obj=obj)
# use a placeholder for 'self' argument
pickle.CloudPickler.dispatch[cls] = _CloudPicklerReducer
else:
# TODO(rkn): We need to be more thoughtful about what to do if
# custom serializers have already been registered for class_id.
# In some cases, we may want to use the last user-defined
# serializers and ignore subsequent calls to
# register_custom_serializer that were made by the system.
serialization_context = worker_info[
"worker"].get_serialization_context(job_id)
serialization_context.register_type(
cls,
class_id,
pickle=use_pickle,
custom_serializer=serializer,
custom_deserializer=deserializer)
if not local:
worker.run_function_on_all_workers(register_class_for_serialization)
else:
# Since we are pickling objects of this class, we don't actually need
# to ship the class definition.
register_class_for_serialization({"worker": worker})
def get(object_ids):
"""Get a remote object or a list of remote objects from the object store.