Source code for ray.actor

import inspect
import logging
import weakref

from abc import ABCMeta, abstractmethod
from collections import namedtuple

import ray.ray_constants as ray_constants
import ray._raylet
import ray.signature as signature
import ray.worker
from ray import ActorClassID, Language
from ray._raylet import PythonFunctionDescriptor
from ray import cross_language

logger = logging.getLogger(__name__)


[docs]def method(*args, **kwargs): """Annotate an actor method. .. code-block:: python @ray.remote class Foo: @ray.method(num_return_vals=2) def bar(self): return 1, 2 f = Foo.remote() _, _ = f.bar.remote() Args: num_return_vals: The number of object IDs that should be returned by invocations of this actor method. """ assert len(args) == 0 assert len(kwargs) == 1 assert "num_return_vals" in kwargs num_return_vals = kwargs["num_return_vals"] def annotate_method(method): method.__ray_num_return_vals__ = num_return_vals return method return annotate_method
# Create objects to wrap method invocations. This is done so that we can # invoke methods with actor.method.remote() instead of actor.method(). class ActorMethod: """A class used to invoke an actor method. Note: This class only keeps a weak ref to the actor, unless it has been passed to a remote function. This avoids delays in GC of the actor. Attributes: _actor: A handle to the actor. _method_name: The name of the actor method. _num_return_vals: The default number of return values that the method invocation should return. _decorator: An optional decorator that should be applied to the actor method invocation (as opposed to the actor method execution) before invoking the method. The decorator must return a function that takes in two arguments ("args" and "kwargs"). In most cases, it should call the function that was passed into the decorator and return the resulting ObjectIDs. For an example, see "test_decorated_method" in "python/ray/tests/test_actor.py". """ def __init__(self, actor, method_name, num_return_vals, decorator=None, hardref=False): self._actor_ref = weakref.ref(actor) self._method_name = method_name self._num_return_vals = num_return_vals # This is a decorator that is used to wrap the function invocation (as # opposed to the function execution). The decorator must return a # function that takes in two arguments ("args" and "kwargs"). In most # cases, it should call the function that was passed into the decorator # and return the resulting ObjectIDs. self._decorator = decorator # Acquire a hard ref to the actor, this is useful mainly when passing # actor method handles to remote functions. if hardref: self._actor_hard_ref = actor else: self._actor_hard_ref = None def __call__(self, *args, **kwargs): raise TypeError("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 self._remote(args, kwargs) def _remote(self, args=None, kwargs=None, num_return_vals=None): if num_return_vals is None: num_return_vals = self._num_return_vals def invocation(args, kwargs): actor = self._actor_hard_ref or self._actor_ref() if actor is None: raise RuntimeError("Lost reference to actor") return actor._actor_method_call( self._method_name, args=args, kwargs=kwargs, num_return_vals=num_return_vals) # Apply the decorator if there is one. if self._decorator is not None: invocation = self._decorator(invocation) return invocation(args, kwargs) def __getstate__(self): return { "actor": self._actor_ref(), "method_name": self._method_name, "num_return_vals": self._num_return_vals, "decorator": self._decorator, } def __setstate__(self, state): self.__init__( state["actor"], state["method_name"], state["num_return_vals"], state["decorator"], hardref=True) class ActorClassMethodMetadata(object): """Metadata for all methods in an actor class. This data can be cached. Attributes: methods: The actor methods. decorators: Optional decorators that should be applied to the method invocation function before invoking the actor methods. These can be set by attaching the attribute "__ray_invocation_decorator__" to the actor method. signatures: The signatures of the methods. num_return_vals: The default number of return values for each actor method. """ _cache = {} # This cache will be cleared in ray.disconnect() def __init__(self): class_name = type(self).__name__ raise TypeError("{} can not be constructed directly, " "instead of running '{}()', try '{}.create()'".format( class_name, class_name, class_name)) @classmethod def reset_cache(cls): cls._cache.clear() @classmethod def create(cls, modified_class, actor_creation_function_descriptor): # Try to create an instance from cache. cached_meta = cls._cache.get(actor_creation_function_descriptor) if cached_meta is not None: return cached_meta # Create an instance without __init__ called. self = cls.__new__(cls) actor_methods = inspect.getmembers(modified_class, ray.utils.is_function_or_method) self.methods = dict(actor_methods) # 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.decorators = {} self.signatures = {} self.num_return_vals = {} for method_name, method in actor_methods: # Whether or not this method requires binding of its first # argument. For class and static methods, we do not want to bind # the first argument, but we do for instance methods is_bound = (ray.utils.is_class_method(method) or ray.utils.is_static_method(modified_class, method_name)) # 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, there may not be much the user can do about it. self.signatures[method_name] = signature.extract_signature( method, ignore_first=not is_bound) # Set the default number of return values for this method. if hasattr(method, "__ray_num_return_vals__"): self.num_return_vals[method_name] = ( method.__ray_num_return_vals__) else: self.num_return_vals[method_name] = ( ray_constants.DEFAULT_ACTOR_METHOD_NUM_RETURN_VALS) if hasattr(method, "__ray_invocation_decorator__"): self.decorators[method_name] = ( method.__ray_invocation_decorator__) # Update cache. cls._cache[actor_creation_function_descriptor] = self return self class ActorClassMetadata: """Metadata for an actor class. Attributes: language: The actor language, e.g. Python, Java. modified_class: The original class that was decorated (with some additional methods added like __ray_terminate__). actor_creation_function_descriptor: The function descriptor for the actor creation task. class_id: The ID of this actor class. class_name: The name of this class. num_cpus: The default number of CPUs required by the actor creation task. num_gpus: The default number of GPUs required by the actor creation task. memory: The heap memory quota for this actor. object_store_memory: The object store memory quota for this actor. resources: The default resources required by the actor creation task. last_export_session_and_job: A pair of the last exported session and job to help us to know whether this function was exported. This is an imperfect mechanism used to determine if we need to export the remote function again. It is imperfect in the sense that the actor class definition could be exported multiple times by different workers. method_meta: The actor method metadata. """ def __init__(self, language, modified_class, actor_creation_function_descriptor, class_id, max_reconstructions, num_cpus, num_gpus, memory, object_store_memory, resources): self.language = language self.modified_class = modified_class self.actor_creation_function_descriptor = \ actor_creation_function_descriptor self.class_name = actor_creation_function_descriptor.class_name self.is_cross_language = language != Language.PYTHON self.class_id = class_id self.max_reconstructions = max_reconstructions self.num_cpus = num_cpus self.num_gpus = num_gpus self.memory = memory self.object_store_memory = object_store_memory self.resources = resources self.last_export_session_and_job = None self.method_meta = ActorClassMethodMetadata.create( modified_class, actor_creation_function_descriptor) class ActorClass: """An actor class. This is a decorated class. It can be used to create actors. Attributes: __ray_metadata__: Contains metadata for the actor. """ def __init__(cls, name, bases, attr): """Prevents users from directly inheriting from an ActorClass. This will be called when a class is defined with an ActorClass object as one of its base classes. To intentionally construct an ActorClass, use the '_ray_from_modified_class' classmethod. Raises: TypeError: Always. """ for base in bases: if isinstance(base, ActorClass): raise TypeError("Attempted to define subclass '{}' of actor " "class '{}'. Inheriting from actor classes is " "not currently supported. You can instead " "inherit from a non-actor base class and make " "the derived class an actor class (with " "@ray.remote).".format( name, base.__ray_metadata__.class_name)) # This shouldn't be reached because one of the base classes must be # an actor class if this was meant to be subclassed. assert False, ("ActorClass.__init__ should not be called. Please use " "the @ray.remote decorator instead.") def __call__(self, *args, **kwargs): """Prevents users from directly instantiating an ActorClass. This will be called instead of __init__ when 'ActorClass()' is executed because an is an object rather than a metaobject. To properly instantiated a remote actor, use 'ActorClass.remote()'. Raises: Exception: Always. """ raise TypeError("Actors cannot be instantiated directly. " "Instead of '{}()', use '{}.remote()'.".format( self.__ray_metadata__.class_name, self.__ray_metadata__.class_name)) @classmethod def _ray_from_modified_class(cls, modified_class, class_id, max_reconstructions, num_cpus, num_gpus, memory, object_store_memory, resources): for attribute in [ "remote", "_remote", "_ray_from_modified_class", "_ray_from_function_descriptor" ]: if hasattr(modified_class, attribute): logger.warning("Creating an actor from class {} overwrites " "attribute {} of that class".format( modified_class.__name__, attribute)) # Make sure the actor class we are constructing inherits from the # original class so it retains all class properties. class DerivedActorClass(cls, modified_class): pass name = "ActorClass({})".format(modified_class.__name__) DerivedActorClass.__module__ = modified_class.__module__ DerivedActorClass.__name__ = name DerivedActorClass.__qualname__ = name # Construct the base object. self = DerivedActorClass.__new__(DerivedActorClass) # Actor creation function descriptor. actor_creation_function_descriptor = \ PythonFunctionDescriptor.from_class( modified_class.__ray_actor_class__) self.__ray_metadata__ = ActorClassMetadata( Language.PYTHON, modified_class, actor_creation_function_descriptor, class_id, max_reconstructions, num_cpus, num_gpus, memory, object_store_memory, resources) return self @classmethod def _ray_from_function_descriptor(cls, language, actor_creation_function_descriptor, max_reconstructions, num_cpus, num_gpus, memory, object_store_memory, resources): self = ActorClass.__new__(ActorClass) self.__ray_metadata__ = ActorClassMetadata( language, None, actor_creation_function_descriptor, None, max_reconstructions, num_cpus, num_gpus, memory, object_store_memory, resources) return self def remote(self, *args, **kwargs): """Create an actor. Args: args: These arguments are forwarded directly to the actor constructor. kwargs: These arguments are forwarded directly to the actor constructor. Returns: A handle to the newly created actor. """ return self._remote(args=args, kwargs=kwargs) def options(self, **options): """Convenience method for creating an actor with options. Same arguments as Actor._remote(), but returns a wrapped actor class that a non-underscore .remote() can be called on. Examples: # The following two calls are equivalent. >>> Actor._remote(num_cpus=4, max_concurrency=8, args=[x, y]) >>> Actor.options(num_cpus=4, max_concurrency=8).remote(x, y) """ actor_cls = self class ActorOptionWrapper: def remote(self, *args, **kwargs): return actor_cls._remote(args=args, kwargs=kwargs, **options) return ActorOptionWrapper() def _remote(self, args=None, kwargs=None, num_cpus=None, num_gpus=None, memory=None, object_store_memory=None, resources=None, is_direct_call=None, max_concurrency=None, name=None, detached=False): """Create an actor. This method allows more flexibility than the remote method because resource requirements can be specified and override the defaults in the decorator. Args: args: The arguments to forward to the actor constructor. kwargs: The keyword arguments to forward to the actor constructor. num_cpus: The number of CPUs required by the actor creation task. num_gpus: The number of GPUs required by the actor creation task. memory: Restrict the heap memory usage of this actor. object_store_memory: Restrict the object store memory used by this actor when creating objects. resources: The custom resources required by the actor creation task. is_direct_call: Use direct actor calls. max_concurrency: The max number of concurrent calls to allow for this actor. This only works with direct actor calls. The max concurrency defaults to 1 for threaded execution, and 1000 for asyncio execution. Note that the execution order is not guaranteed when max_concurrency > 1. name: The globally unique name for the actor. detached: Whether the actor should be kept alive after driver exits. Returns: A handle to the newly created actor. """ if args is None: args = [] if kwargs is None: kwargs = {} if is_direct_call is not None and not is_direct_call: raise ValueError("Non-direct call actors are no longer supported.") meta = self.__ray_metadata__ actor_has_async_methods = len( inspect.getmembers( meta.modified_class, predicate=inspect.iscoroutinefunction)) > 0 is_asyncio = actor_has_async_methods if max_concurrency is None: if is_asyncio: max_concurrency = 1000 else: max_concurrency = 1 if max_concurrency < 1: raise ValueError("max_concurrency must be >= 1") worker = ray.worker.global_worker if worker.mode is None: raise RuntimeError("Actors cannot be created before ray.init() " "has been called.") if detached and name is None: raise ValueError("Detached actors must be named. " "Please use Actor._remote(name='some_name') " "to associate the name.") # Check whether the name is already taken. if name is not None: try: ray.util.get_actor(name) except ValueError: # name is not taken, expected. pass else: raise ValueError( "The name {name} is already taken. Please use " "a different name or get existing actor using " "ray.util.get_actor('{name}')".format(name=name)) # Set the actor's default resources if not already set. First three # conditions are to check that no resources were specified in the # decorator. Last three conditions are to check that no resources were # specified when _remote() was called. if (meta.num_cpus is None and meta.num_gpus is None and meta.resources is None and num_cpus is None and num_gpus is None and resources is None): # In the default case, actors acquire no resources for # their lifetime, and actor methods will require 1 CPU. cpus_to_use = ray_constants.DEFAULT_ACTOR_CREATION_CPU_SIMPLE actor_method_cpu = ray_constants.DEFAULT_ACTOR_METHOD_CPU_SIMPLE else: # If any resources are specified (here or in decorator), then # all resources are acquired for the actor's lifetime and no # resources are associated with methods. cpus_to_use = (ray_constants.DEFAULT_ACTOR_CREATION_CPU_SPECIFIED if meta.num_cpus is None else meta.num_cpus) actor_method_cpu = ray_constants.DEFAULT_ACTOR_METHOD_CPU_SPECIFIED # LOCAL_MODE cannot handle cross_language if worker.mode == ray.LOCAL_MODE: assert not meta.is_cross_language, \ "Cross language ActorClass cannot be executed locally." # Export the actor. if not meta.is_cross_language and (meta.last_export_session_and_job != worker.current_session_and_job): # If this actor class was not exported in this session and job, # we need to export this function again, because current GCS # doesn't have it. meta.last_export_session_and_job = (worker.current_session_and_job) # After serialize / deserialize modified class, the __module__ # of modified class will be ray.cloudpickle.cloudpickle. # So, here pass actor_creation_function_descriptor to make # sure export actor class correct. worker.function_actor_manager.export_actor_class( meta.modified_class, meta.actor_creation_function_descriptor, meta.method_meta.methods.keys()) resources = ray.utils.resources_from_resource_arguments( cpus_to_use, meta.num_gpus, meta.memory, meta.object_store_memory, meta.resources, num_cpus, num_gpus, memory, object_store_memory, resources) # If the actor methods require CPU resources, then set the required # placement resources. If actor_placement_resources is empty, then # the required placement resources will be the same as resources. actor_placement_resources = {} assert actor_method_cpu in [0, 1] if actor_method_cpu == 1: actor_placement_resources = resources.copy() actor_placement_resources["CPU"] += 1 if meta.is_cross_language: creation_args = cross_language.format_args(worker, args, kwargs) else: function_signature = meta.method_meta.signatures["__init__"] creation_args = signature.flatten_args(function_signature, args, kwargs) actor_id = worker.core_worker.create_actor( meta.language, meta.actor_creation_function_descriptor, creation_args, meta.max_reconstructions, resources, actor_placement_resources, max_concurrency, detached, is_asyncio, # Store actor_method_cpu in actor handle's extension data. extension_data=str(actor_method_cpu)) actor_handle = ActorHandle( meta.language, actor_id, meta.method_meta.decorators, meta.method_meta.signatures, meta.method_meta.num_return_vals, actor_method_cpu, meta.actor_creation_function_descriptor, worker.current_session_and_job, original_handle=True) if name is not None: ray.util.register_actor(name, actor_handle) return actor_handle class ActorHandle: """A handle to an actor. The fields in this class are prefixed with _ray_ to hide them from the user and to avoid collision with actor method names. An ActorHandle can be created in three ways. First, by calling .remote() on an ActorClass. Second, by passing an actor handle into a task (forking the ActorHandle). Third, by directly serializing the ActorHandle (e.g., with cloudpickle). Attributes: _ray_actor_language: The actor language. _ray_actor_id: Actor ID. _ray_method_decorators: Optional decorators for the function invocation. This can be used to change the behavior on the invocation side, whereas a regular decorator can be used to change the behavior on the execution side. _ray_method_signatures: The signatures of the actor methods. _ray_method_num_return_vals: The default number of return values for each method. _ray_actor_method_cpus: The number of CPUs required by actor methods. _ray_original_handle: True if this is the original actor handle for a given actor. If this is true, then the actor will be destroyed when this handle goes out of scope. _ray_is_cross_language: Whether this actor is cross language. _ray_actor_creation_function_descriptor: The function descriptor of the actor creation task. """ def __init__(self, language, actor_id, method_decorators, method_signatures, method_num_return_vals, actor_method_cpus, actor_creation_function_descriptor, session_and_job, original_handle=False): self._ray_actor_language = language self._ray_actor_id = actor_id self._ray_original_handle = original_handle self._ray_method_decorators = method_decorators self._ray_method_signatures = method_signatures self._ray_method_num_return_vals = method_num_return_vals self._ray_actor_method_cpus = actor_method_cpus self._ray_session_and_job = session_and_job self._ray_is_cross_language = language != Language.PYTHON self._ray_actor_creation_function_descriptor = \ actor_creation_function_descriptor self._ray_function_descriptor = {} if not self._ray_is_cross_language: assert isinstance(actor_creation_function_descriptor, PythonFunctionDescriptor) module_name = actor_creation_function_descriptor.module_name class_name = actor_creation_function_descriptor.class_name for method_name in self._ray_method_signatures.keys(): function_descriptor = PythonFunctionDescriptor( module_name, method_name, class_name) self._ray_function_descriptor[ method_name] = function_descriptor method = ActorMethod( self, method_name, self._ray_method_num_return_vals[method_name], decorator=self._ray_method_decorators.get(method_name)) setattr(self, method_name, method) def __del__(self): # Mark that this actor handle has gone out of scope. Once all actor # handles are out of scope, the actor will exit. worker = ray.worker.global_worker if worker.connected and hasattr(worker, "core_worker"): worker.core_worker.remove_actor_handle_reference( self._ray_actor_id) def _actor_method_call(self, method_name, args=None, kwargs=None, num_return_vals=None): """Method execution stub for an actor handle. This is the function that executes when `actor.method_name.remote(*args, **kwargs)` is called. Instead of executing locally, the method is packaged as a task and scheduled to the remote actor instance. Args: method_name: The name of the actor method to execute. args: A list of arguments for the actor method. kwargs: A dictionary of keyword arguments for the actor method. num_return_vals (int): The number of return values for the method. Returns: object_ids: A list of object IDs returned by the remote actor method. """ worker = ray.worker.global_worker args = args or [] kwargs = kwargs or {} if self._ray_is_cross_language: list_args = cross_language.format_args(worker, args, kwargs) function_descriptor = \ cross_language.get_function_descriptor_for_actor_method( self._ray_actor_language, self._ray_actor_creation_function_descriptor, method_name) else: function_signature = self._ray_method_signatures[method_name] if not args and not kwargs and not function_signature: list_args = [] else: list_args = signature.flatten_args(function_signature, args, kwargs) function_descriptor = self._ray_function_descriptor[method_name] if worker.mode == ray.LOCAL_MODE: assert not self._ray_is_cross_language,\ "Cross language remote actor method " \ "cannot be executed locally." object_ids = worker.core_worker.submit_actor_task( self._ray_actor_language, self._ray_actor_id, function_descriptor, list_args, num_return_vals, self._ray_actor_method_cpus) if len(object_ids) == 1: object_ids = object_ids[0] elif len(object_ids) == 0: object_ids = None return object_ids def __getattr__(self, item): if not self._ray_is_cross_language: raise AttributeError("'{}' object has no attribute '{}'".format( type(self).__name__, item)) if item in ["__ray_terminate__", "__ray_checkpoint__"]: class FakeActorMethod(object): def __call__(self, *args, **kwargs): raise TypeError( "Actor methods cannot be called directly. Instead " "of running 'object.{}()', try 'object.{}.remote()'.". format(item, item)) def remote(self, *args, **kwargs): logger.warning( "Actor method {} is not supported by cross language." .format(item)) return FakeActorMethod() return ActorMethod( self, item, ray_constants. # Currently, we use default num returns DEFAULT_ACTOR_METHOD_NUM_RETURN_VALS, # Currently, cross-lang actor method not support decorator decorator=None) # Make tab completion work. def __dir__(self): return self._ray_method_signatures.keys() def __repr__(self): return "Actor({}, {})".format( self._ray_actor_creation_function_descriptor.class_name, self._actor_id.hex()) def __ray_kill__(self): """Deprecated - use ray.kill() instead.""" logger.warning("actor.__ray_kill__() is deprecated and will be removed" " in the near future. Use ray.kill(actor) instead.") ray.kill(self) @property def _actor_id(self): return self._ray_actor_id def _serialization_helper(self): """This is defined in order to make pickling work. Returns: A dictionary of the information needed to reconstruct the object. """ worker = ray.worker.global_worker worker.check_connected() if hasattr(worker, "core_worker"): # Non-local mode state = worker.core_worker.serialize_actor_handle( self._ray_actor_id) else: # Local mode state = ({ "actor_language": self._ray_actor_language, "actor_id": self._ray_actor_id, "method_decorators": self._ray_method_decorators, "method_signatures": self._ray_method_signatures, "method_num_return_vals": self._ray_method_num_return_vals, "actor_method_cpus": self._ray_actor_method_cpus, "actor_creation_function_descriptor": self. _ray_actor_creation_function_descriptor, }, None) return state @classmethod def _deserialization_helper(cls, state, outer_object_id=None): """This is defined in order to make pickling work. Args: state: The serialized state of the actor handle. outer_object_id: The ObjectID that the serialized actor handle was contained in, if any. This is used for counting references to the actor handle. """ worker = ray.worker.global_worker worker.check_connected() if hasattr(worker, "core_worker"): # Non-local mode return worker.core_worker.deserialize_and_register_actor_handle( state, outer_object_id) else: # Local mode return cls( # TODO(swang): Accessing the worker's current task ID is not # thread-safe. state["actor_language"], state["actor_id"], state["method_decorators"], state["method_signatures"], state["method_num_return_vals"], state["actor_method_cpus"], state["actor_creation_function_descriptor"], worker.current_session_and_job) def __reduce__(self): """This code path is used by pickling but not by Ray forking.""" state = self._serialization_helper() return ActorHandle._deserialization_helper, (state) def modify_class(cls): # cls has been modified. if hasattr(cls, "__ray_actor_class__"): return cls # Give an error if cls is an old-style class. if not issubclass(cls, object): raise TypeError( "The @ray.remote decorator cannot be applied to old-style " "classes. In Python 2, you must declare the class with " "'class ClassName(object):' instead of 'class ClassName:'.") if issubclass(cls, Checkpointable) and inspect.isabstract(cls): raise TypeError( "A checkpointable actor class should implement all abstract " "methods in the `Checkpointable` interface.") # Modify the class to have an additional method that will be used for # terminating the worker. class Class(cls): __ray_actor_class__ = cls # The original actor class def __ray_terminate__(self): worker = ray.worker.global_worker if worker.mode != ray.LOCAL_MODE: ray.actor.exit_actor() def __ray_checkpoint__(self): """Save a checkpoint. This task saves the current state of the actor, the current task frontier according to the raylet, and the checkpoint index (number of tasks executed so far). """ worker = ray.worker.global_worker if not isinstance(self, ray.actor.Checkpointable): raise TypeError( "__ray_checkpoint__.remote() may only be called on actors " "that implement ray.actor.Checkpointable") return worker._save_actor_checkpoint() Class.__module__ = cls.__module__ Class.__name__ = cls.__name__ if not ray.utils.is_function_or_method(getattr(Class, "__init__", None)): # Add __init__ if it does not exist. # Actor creation will be executed with __init__ together. # Assign an __init__ function will avoid many checks later on. def __init__(self): pass Class.__init__ = __init__ return Class def make_actor(cls, num_cpus, num_gpus, memory, object_store_memory, resources, max_reconstructions): Class = modify_class(cls) if max_reconstructions is None: max_reconstructions = 0 if not (ray_constants.NO_RECONSTRUCTION <= max_reconstructions <= ray_constants.INFINITE_RECONSTRUCTION): raise ValueError("max_reconstructions must be in range [%d, %d]." % (ray_constants.NO_RECONSTRUCTION, ray_constants.INFINITE_RECONSTRUCTION)) return ActorClass._ray_from_modified_class( Class, ActorClassID.from_random(), max_reconstructions, num_cpus, num_gpus, memory, object_store_memory, resources) def exit_actor(): """Intentionally exit the current actor. This function is used to disconnect an actor and exit the worker. Raises: Exception: An exception is raised if this is a driver or this worker is not an actor. """ worker = ray.worker.global_worker if worker.mode == ray.WORKER_MODE and not worker.actor_id.is_nil(): # Intentionally disconnect the core worker from the raylet so the # raylet won't push an error message to the driver. ray.disconnect() # Disconnect global state from GCS. ray.state.state.disconnect() # Set a flag to indicate this is an intentional actor exit. This # reduces log verbosity. exit = SystemExit(0) exit.is_ray_terminate = True raise exit assert False, "This process should have terminated." else: raise TypeError("exit_actor called on a non-actor worker.") CheckpointContext = namedtuple( "CheckpointContext", [ # Actor's ID. "actor_id", # Number of tasks executed since last checkpoint. "num_tasks_since_last_checkpoint", # Time elapsed since last checkpoint, in milliseconds. "time_elapsed_ms_since_last_checkpoint", ], ) """A namedtuple that contains information about actor's last checkpoint.""" Checkpoint = namedtuple( "Checkpoint", [ # ID of this checkpoint. "checkpoint_id", # The timestamp at which this checkpoint was saved, # represented as milliseconds elapsed since Unix epoch. "timestamp", ], ) """A namedtuple that represents a checkpoint.""" class Checkpointable(metaclass=ABCMeta): """An interface that indicates an actor can be checkpointed.""" @abstractmethod def should_checkpoint(self, checkpoint_context): """Whether this actor needs to be checkpointed. This method will be called after every task. You should implement this callback to decide whether this actor needs to be checkpointed at this time, based on the checkpoint context, or any other factors. Args: checkpoint_context: A namedtuple that contains info about last checkpoint. Returns: A boolean value that indicates whether this actor needs to be checkpointed. """ pass @abstractmethod def save_checkpoint(self, actor_id, checkpoint_id): """Save a checkpoint to persistent storage. If `should_checkpoint` returns true, this method will be called. You should implement this callback to save actor's checkpoint and the given checkpoint id to persistent storage. Args: actor_id: Actor's ID. checkpoint_id: ID of this checkpoint. You should save it together with actor's checkpoint data. And it will be used by the `load_checkpoint` method. Returns: None. """ pass @abstractmethod def load_checkpoint(self, actor_id, available_checkpoints): """Load actor's previous checkpoint, and restore actor's state. This method will be called when an actor is reconstructed, after actor's constructor. If the actor needs to restore from previous checkpoint, this function should restore actor's state and return the checkpoint ID. Otherwise, it should do nothing and return None. Note, this method must return one of the checkpoint IDs in the `available_checkpoints` list, or None. Otherwise, an exception will be raised. Args: actor_id: Actor's ID. available_checkpoints: A list of `Checkpoint` namedtuples that contains all available checkpoint IDs and their timestamps, sorted by timestamp in descending order. Returns: The ID of the checkpoint from which the actor was resumed, or None if the actor should restart from the beginning. """ pass @abstractmethod def checkpoint_expired(self, actor_id, checkpoint_id): """Delete an expired checkpoint. This method will be called when an checkpoint is expired. You should implement this method to delete your application checkpoint data. Note, the maximum number of checkpoints kept in the backend can be configured at `RayConfig.num_actor_checkpoints_to_keep`. Args: actor_id: ID of the actor. checkpoint_id: ID of the checkpoint that has expired. Returns: None. """ pass def get_checkpoints_for_actor(actor_id): """Get the available checkpoints for the given actor ID, return a list sorted by checkpoint timestamp in descending order. """ checkpoint_info = ray.state.state.actor_checkpoint_info(actor_id) if checkpoint_info is None: return [] checkpoints = [ Checkpoint(checkpoint_id, timestamp) for checkpoint_id, timestamp in zip(checkpoint_info["CheckpointIds"], checkpoint_info["Timestamps"]) ] return sorted( checkpoints, key=lambda checkpoint: checkpoint.timestamp, reverse=True, )