rotor::actor_base_t Struct Reference

universal primitive of concurrent computation More...

#include <actor_base.h>

Inheritance diagram for rotor::actor_base_t:

Public Types
using	config_t = actor_config_t
	injects an alias for actor_config_t
template<typename Actor>
using	config_builder_t = actor_config_builder_t<Actor>
	injects templated actor_config_builder_t
template<typename Handler>
using	is_handler
	SFINAE handler detector.
using	plugins_list_t
	the default list of plugins for an actor

Public Member Functions
	actor_base_t (config_t &cfg)
	constructs actor and links it's supervisor
virtual void	do_initialize (system_context_t *ctx) noexcept
	early actor initialization (pre-initialization)
virtual void	do_shutdown (const extended_error_ptr_t &reason={}) noexcept
	convenient method to send actor's supervisor shutdown trigger message
virtual void	on_start () noexcept
	actor is fully initialized and it's supervisor has sent signal to start
template<typename M, typename... Args>
void	send (const address_ptr_t &addr, Args &&...args)
	sends message to the destination address
template<typename M, typename... Args>
void	route (const address_ptr_t &addr, const address_ptr_t &next_addr, Args &&...args)
	routes message to the destination address, then to the next address
void	redirect (message_ptr_t message, const address_ptr_t &addr, const address_ptr_t &next_addr={}) noexcept
	redirects premade message into destination address (and them, possibly routes it to `next_address)
template<typename R, typename... Args>
request_builder_t< typename request_wrapper_t< R >::request_t >	request (const address_ptr_t &dest_addr, Args &&...args)
	returns request builder for destination address using the "main" actor address
template<typename R, typename... Args>
request_builder_t< typename request_wrapper_t< R >::request_t >	request_via (const address_ptr_t &dest_addr, const address_ptr_t &reply_addr, Args &&...args)
	returns request builder for destination address using the specified address for reply
template<typename Request, typename... Args>
void	reply_to (Request &message, Args &&...args)
	convenient method for constructing and sending response to a request
template<typename Request>
void	reply_with_error (Request &message, const extended_error_ptr_t &ec)
	convenient method for constructing and sending error response to a request
template<typename Request, typename... Args>
auto	make_response (Request &message, Args &&...args)
	makes response to the request, but does not send it.
template<typename Request>
auto	make_response (Request &message, const extended_error_ptr_t &ec)
	makes error response to the request, but does not send it.
template<typename Handler>
subscription_info_ptr_t	subscribe (Handler &&h, const address_ptr_t &addr) noexcept
	subscribes actor's handler to process messages on the specified address
template<typename Handler>
subscription_info_ptr_t	subscribe (Handler &&h) noexcept
	subscribes actor's handler to process messages on the actor's "main" address
template<typename Handler, typename = is_handler<Handler>>
void	unsubscribe (Handler &&h, address_ptr_t &addr) noexcept
	unsubscribes actor's handler from process messages on the specified address
template<typename Handler, typename = is_handler<Handler>>
void	unsubscribe (Handler &&h) noexcept
	unsubscribes actor's handler from processing messages on the actor's "main" address
void	unsubscribe (const handler_ptr_t &h) noexcept
	initiates handler unsubscription from the default actor address
void	activate_plugins () noexcept
	starts plugins activation
void	commit_plugin_activation (plugin::plugin_base_t &plugin, bool success) noexcept
	finishes plugin activation, successful or not
void	deactivate_plugins () noexcept
	starts plugins deactivation
void	commit_plugin_deactivation (plugin::plugin_base_t &plugin) noexcept
	finishes plugin deactivation
void	on_subscription (message::subscription_t &message) noexcept
	propagates subscription message to corresponding actors
void	on_unsubscription (message::unsubscription_t &message) noexcept
	propagates unsubscription message to corresponding actors
void	on_unsubscription_external (message::unsubscription_external_t &message) noexcept
	propagates external unsubscription message to corresponding actors
address_ptr_t	create_address () noexcept
	creates new unique address for an actor (via address_maker plugin)
virtual void	shutdown_start () noexcept
	starts shutdown procedure, e.g. upon receiving shutdown request
void	shutdown_continue () noexcept
	polls plugins for shutdown
virtual void	shutdown_finish () noexcept
	finalizes shutdown
virtual void	init_start () noexcept
	starts initialization procedure
void	init_continue () noexcept
	polls plugins whether they completed initialization.
virtual void	init_finish () noexcept
	finalizes initialization
virtual void	configure (plugin::plugin_base_t &plugin) noexcept
	main callback for plugin configuration when it's ready
template<typename T>
auto &	access () noexcept
	generic non-public fields accessor
template<typename T, typename... Args>
auto	access (Args... args) noexcept
	generic non-public methods accessor
template<typename T>
auto &	access () const noexcept
	generic non-public fields accessor
template<typename T, typename... Args>
auto	access (Args... args) const noexcept
	generic non-public methods accessor
const address_ptr_t &	get_address () const noexcept
	returns actor's main address
supervisor_t &	get_supervisor () const noexcept
	returns actor's supervisor
template<typename Delegate, typename Method, typename = std::enable_if_t<std::is_invocable_v<Method, Delegate *, request_id_t, bool>>>
request_id_t	start_timer (const pt::time_duration &interval, Delegate &delegate, Method method) noexcept
	spawns a new one-shot timer
void	cancel_timer (request_id_t request_id) noexcept
	cancels previously started timer
const extended_error_ptr_t &	get_shutdown_reason () const noexcept
	returns actor shutdown reason
const std::string &	get_identity () const noexcept
	retuns human-readable actor identity
virtual bool	should_restart () const noexcept
	whether spawner should create a new instance of the actor
template<typename Request, typename... Args>
request_builder_t< typename request_wrapper_t< Request >::request_t >	request (const address_ptr_t &dest_addr, Args &&...args)
	makes an request to the destination address with the message constructed from args
template<typename Request, typename... Args>
request_builder_t< typename request_wrapper_t< Request >::request_t >	request_via (const address_ptr_t &dest_addr, const address_ptr_t &reply_addr, Args &&...args)
	makes an request to the destination address with the message constructed from args

Static Public Attributes
static const constexpr std::uint32_t	PROGRESS_INIT = 1 << 0
	flag to mark, that actor is already executing initialization
static const constexpr std::uint32_t	PROGRESS_SHUTDOWN = 1 << 1
	flag to mark, that actor is already executing shutdown
static const constexpr std::uint32_t	ESCALATE_FALIURE = 1 << 2
	flag to mark, that actor is already executing shutdown
static const constexpr std::uint32_t	AUTOSHUTDOWN_SUPERVISOR = 1 << 3
	flag to mark, that actor trigger supervisor shutdown

Protected Types
using	timers_map_t = std::unordered_map<request_id_t, timer_handler_ptr_t>
	timer-id to timer-handler map (type)
using	requests_t = std::unordered_set<request_id_t>
	list of ids of active requests (type)

Protected Member Functions
void	on_timer_trigger (request_id_t request_id, bool cancelled) noexcept
	triggers timer handler associated with the timer id
template<typename Delegate, typename Method>
void	start_timer (request_id_t request_id, const pt::time_duration &interval, Delegate &delegate, Method method) noexcept
	starts timer with pre-forged timer id (aka request-id
void	assign_shutdown_reason (extended_error_ptr_t reason) noexcept
	helper-method, which assigns shutdown reason if it isn't set
extended_error_ptr_t	make_error (const std::error_code &ec, const extended_error_ptr_t &next={}, const message_ptr_t &request={}) const noexcept
	makes extended error within the context of the actor
virtual bool	on_unlink (const address_ptr_t &server_addr) noexcept
	notification, when actor has been unlinked from server actor
plugin::plugin_base_t *	get_plugin (const std::type_index &) const noexcept
	finds plugin by plugin class identity

Protected Attributes
intrusive_ptr_t< message::init_request_t >	init_request
	suspended init request message
intrusive_ptr_t< message::shutdown_request_t >	shutdown_request
	suspended shutdown request message
address_ptr_t	address
	actor address
address_ptr_t	spawner_address
	actor spawner address
std::string	identity
	actor identity, which might have some meaning for developers
supervisor_t *	supervisor
	non-owning pointer to actor's execution / infrastructure context
plugin_storage_ptr_t	plugins_storage
	opaque plugins storage (owning)
plugins_t	plugins
	non-owning list of plugins
pt::time_duration	init_timeout
	timeout for actor initialization (used by supervisor)
pt::time_duration	shutdown_timeout
	timeout for actor shutdown (used by supervisor)
state_t	state
	current actor state
plugin::address_maker_plugin_t *	address_maker = nullptr
	non-owning pointer to address_maker plugin
plugin::lifetime_plugin_t *	lifetime = nullptr
	non-owning pointer to lifetime plugin
plugin::link_server_plugin_t *	link_server = nullptr
	non-owning pointer to link_server plugin
plugin::resources_plugin_t *	resources = nullptr
	non-owning pointer to resources plugin
std::set< const std::type_index * >	activating_plugins
	set of activating plugin identities
std::set< const std::type_index * >	deactivating_plugins
	set of deactivating plugin identities
timers_map_t	timers_map
	timer-id to timer-handler map
requests_t	active_requests
	list of ids of active requests
std::uint32_t	continuation_mask = 0
	set of currently processing states, i.e. init or shutdown
extended_error_ptr_t	shutdown_reason
	explanation, why actor is been requested for shut down

Friends
struct	plugin::plugin_base_t
struct	plugin::lifetime_plugin_t
struct	supervisor_t
template<typename T>
struct	request_builder_t
template<typename T, typename M>
struct	accessor_t

Detailed Description

universal primitive of concurrent computation

The class is base class for user-defined actors. It is expected that actors will react on incoming messages (e.g. by changing internal /private state) or send (other) messages to other actors, or do some side-effects (I/O, etc.).

Message passing interface is asynchronous, they are send to supervisor_t.

Every actor belong to some supervisor_t, which "injects" the thread-safe execution context, in a sense, that the actor can call it's own methods as well as supervisors without any need of synchronization.

All actor methods are thread-unsafe, i.e. should not be called with except of it's own supervisor. Communication with actor should be performed via messages.

Actor is addressed by it's "main" address; however it is possible for an actor to have multiple identities aka "virtual" addresses.

Member Typedef Documentation

is_handler

template<typename Handler>

using rotor::actor_base_t::is_handler

Initial value:

 
        std::enable_if_t<std::is_member_function_pointer_v<Handler> || std::is_base_of_v<handler_base_t, Handler>>

SFINAE handler detector.

Either handler can be constructed from member-to-function-pointer or it is already constructed and have a base handler_base_t

plugins_list_t

using rotor::actor_base_t::plugins_list_t

Initial value:

 std::tuple<
        plugin::address_maker_plugin_t,
        plugin::lifetime_plugin_t,
        plugin::init_shutdown_plugin_t,
        plugin::link_server_plugin_t,
        plugin::link_client_plugin_t,
        plugin::registry_plugin_t,
        plugin::resources_plugin_t,
        plugin::starter_plugin_t>

the default list of plugins for an actor

The order of plugins is very important, as they are initialized in the direct order and deinitialized in the reverse order.

Constructor & Destructor Documentation

actor_base_t()

rotor::actor_base_t::actor_base_t

(

config_t &

cfg

)

constructs actor and links it's supervisor

An actor cannot outlive it's supervisor.

Sets internal actor state to NEW

Member Function Documentation

cancel_timer()

void rotor::actor_base_t::cancel_timer ( request_id_t request_id )

noexcept

cancels previously started timer

If timer hasn't been triggered, then it is cancelled and the callback will be invoked with true to mark that it was cancelled.

Upon cancellation the timer callback will be invoked immediately, in the context of caller.

configure()

virtual void rotor::actor_base_t::configure ( plugin::plugin_base_t & plugin )

virtualnoexcept

main callback for plugin configuration when it's ready

Reimplemented in rotor::registry_t.

do_initialize()

virtual void rotor::actor_base_t::do_initialize ( system_context_t * ctx )

virtualnoexcept

early actor initialization (pre-initialization)

Actor's plugins are activated, "main" address is created (via plugin::address_maker_plugin_t), state is set to INITIALIZING (via plugin::init_shutdown_plugin_t).

Reimplemented in rotor::ev::supervisor_ev_t, and rotor::supervisor_t.

do_shutdown()

virtual void rotor::actor_base_t::do_shutdown ( const extended_error_ptr_t & reason = {} )

virtualnoexcept

convenient method to send actor's supervisor shutdown trigger message

If actor is already shutting down, the method will do nothing, otherwise it will send shutdown trigger to its supervisor.

The shutdown reason is forwarded "as is". If it is missing, than it will be constructed with the error code "normal shutdown".

Reimplemented in rotor::supervisor_t.

get_identity()

const std::string & rotor::actor_base_t::get_identity ( ) const

inlinenoexcept

retuns human-readable actor identity

The identity can be assigned either directly in ctor, or via address_maker plugin

get_plugin()

plugin::plugin_base_t * rotor::actor_base_t::get_plugin ( const std::type_index & ) const

protectednoexcept

finds plugin by plugin class identity

nullptr is returned when plugin cannot be found

get_shutdown_reason()

const extended_error_ptr_t & rotor::actor_base_t::get_shutdown_reason ( ) const

inlinenoexcept

returns actor shutdown reason

The shutdown reason should be available if actors' state is already SHUTTING_DOWN

init_continue()

void rotor::actor_base_t::init_continue ( )

noexcept

polls plugins whether they completed initialization.

The poll is performed in the direct order. If all plugins, with active init reaction confirm they are ready, then the init_finish method is invoked.

init_finish()

virtual void rotor::actor_base_t::init_finish ( )

virtualnoexcept

finalizes initialization

The init response is sent and actor state is set to INITIALIZED.

init_start()

virtual void rotor::actor_base_t::init_start ( )

virtualnoexcept

starts initialization procedure

The actor state is set to INITIALIZING.

make_response() [1/2]

template<typename Request, typename... Args>

auto rotor::actor_base_t::make_response	(	Request &	message,
		Args &&...	args )

makes response to the request, but does not send it.

The return type is intrusive pointer to the message, not the message itself.

It can be useful for delayed responses. The response can be dispatched later via supervisor->put(std::move(response_ptr));

make_response() [2/2]

template<typename Request>

auto rotor::actor_base_t::make_response	(	Request &	message,
		const extended_error_ptr_t &	ec )

makes error response to the request, but does not send it.

The return type is intrusive pointer to the message, not the message itself.

It can be useful for delayed responses. The response can be dispatched later via supervisor->put(std::move(response_ptr));

on_start()

virtual void rotor::actor_base_t::on_start ( )

virtualnoexcept

actor is fully initialized and it's supervisor has sent signal to start

The actor state is set to OPERATIONAL.

Reimplemented in rotor::supervisor_t.

on_unlink()

virtual bool rotor::actor_base_t::on_unlink ( const address_ptr_t & server_addr )

protectedvirtualnoexcept

notification, when actor has been unlinked from server actor

Returns boolean, meaning whether actor should initiate shutdown. Default value is true.

reply_to()

template<typename Request, typename... Args>

void rotor::actor_base_t::reply_to	(	Request &	message,
		Args &&...	args )

convenient method for constructing and sending response to a request

args are forwarded to response payload construction

request() [1/2]

template<typename R, typename... Args>

request_builder_t< typename request_wrapper_t< R >::request_t > rotor::actor_base_t::request	(	const address_ptr_t &	dest_addr,
		Args &&...	args )

returns request builder for destination address using the "main" actor address

The args are forwarded for construction of the request. The request is not actually sent, until send method of request_builder_t will be invoked.

Supervisor will spawn timeout timer upon timeout method.

request() [2/2]

template<typename Request, typename... Args>

request_builder_t< typename request_wrapper_t< Request >::request_t > rotor::actor_base_t::request	(	const address_ptr_t &	dest_addr,
		Args &&...	args )

makes an request to the destination address with the message constructed from args

The reply_to address is defaulted to actor's main address.1

request_via() [1/2]

template<typename R, typename... Args>

request_builder_t< typename request_wrapper_t< R >::request_t > rotor::actor_base_t::request_via	(	const address_ptr_t &	dest_addr,
		const address_ptr_t &	reply_addr,
		Args &&...	args )

returns request builder for destination address using the specified address for reply

It is assumed, that the specified address belongs to the actor.

The method is useful, when a different behavior is needed for the same message response types. It serves at some extend as virtual dispatching within the actor.

See the description of request method.

request_via() [2/2]

template<typename Request, typename... Args>

request_builder_t< typename request_wrapper_t< Request >::request_t > rotor::actor_base_t::request_via	(	const address_ptr_t &	dest_addr,
		const address_ptr_t &	reply_addr,
		Args &&...	args )

makes an request to the destination address with the message constructed from args

The reply_addr is used to specify the exact destination address, where reply should be delivered.

route()

template<typename M, typename... Args>

void rotor::actor_base_t::route	(	const address_ptr_t &	addr,
		const address_ptr_t &	next_addr,
		Args &&...	args )

routes message to the destination address, then to the next address

The provided arguments are used for the construction of payload, which is, in turn, is wrapped into message.

Internally the new message is placed into supervisor's outbound queue.

The message routing is performed upon last address delivery, then, when ref_counter is 1, message address is chenaged to the next_addr and the next_addr is nullified.

The whole mechanics is based on ref-counting mechanism. That means, if the message is captured into intrusive_ptr somewhere it will NOT be routed. It have to be manually redirected then.

send()

template<typename M, typename... Args>

void rotor::actor_base_t::send	(	const address_ptr_t &	addr,
		Args &&...	args )

sends message to the destination address

The provided arguments are used for the construction of payload, which is, in turn, is wrapped into message.

Internally the new message is placed into supervisor's outbound queue.

should_restart()

virtual bool rotor::actor_base_t::should_restart ( ) const

virtualnoexcept

whether spawner should create a new instance of the actor

When then actor is spawned via a spawner, and it becomes down, the spawner will ask the current instance whether it should spawn another one.

This method is consulted, only when spawner's restart_policy_t is ask_actor.

shutdown_continue()

void rotor::actor_base_t::shutdown_continue ( )

noexcept

polls plugins for shutdown

The poll is performed in the reverse order. If all plugins, with active shutdown reaction confirm they are ready to shutdown, then the shutdown_finish method is invoked.

shutdown_finish()

virtual void rotor::actor_base_t::shutdown_finish ( )

virtualnoexcept

finalizes shutdown

The shutdown response is sent and actor state is set to SHUT_DOWN.

This is the last action in the shutdown sequence. No further methods will be invoked on the actor.

All unfinished requests and untriggered timers will be cancelled by force in the method.

Reimplemented in rotor::asio::supervisor_asio_t, rotor::ev::supervisor_ev_t, and rotor::supervisor_t.

shutdown_start()

virtual void rotor::actor_base_t::shutdown_start ( )

virtualnoexcept

starts shutdown procedure, e.g. upon receiving shutdown request

The actor state is set to SHUTTING_DOWN.

start_timer()

template<typename Delegate, typename Method, typename>

request_id_t rotor::actor_base_t::start_timer ( const pt::time_duration & interval, Delegate & delegate, Method method )

noexcept

spawns a new one-shot timer

Parameters

interval	specifies amount of time, after which the timer will trigger.
delegate	is an object of arbitrary class.
method	is the pointer-to-member-function of the object or callback, which will be invoked upon timer triggering or cancellation.

The method parameter should have the following signatures:

void Delegate::on_timer(request_id_t, bool cancelled) noexcept;

or

void(Delegate*,request_id_t, bool cancelled) noexcept

start_timer returns timer identity. It will be supplied to the specified callback, or the timer can be cancelled via it.

Member Data Documentation

AUTOSHUTDOWN_SUPERVISOR

const constexpr std::uint32_t rotor::actor_base_t::AUTOSHUTDOWN_SUPERVISOR = 1 << 3

staticconstexpr

flag to mark, that actor trigger supervisor shutdown

When actor is shutdown (for whatever reason), if this flag is ON, then it will trigger it's supervisor shutdown.

This policy is ignored when actor is spawned.

continuation_mask

std::uint32_t rotor::actor_base_t::continuation_mask = 0

protected

set of currently processing states, i.e. init or shutdown

This is not the same as state_t flag, which just marks the state.

The continuation_mask is mostly used by plugins to avoid recursion

ESCALATE_FALIURE

const constexpr std::uint32_t rotor::actor_base_t::ESCALATE_FALIURE = 1 << 2

staticconstexpr

flag to mark, that actor is already executing shutdown

When actor is shutdown due to failure, if this flag is ON, then it will trigger it's supervisor shutdown.

This policy is ignored when actor is spawned.

---

The documentation for this struct was generated from the following files:

• /home/b/development/cpp/cpp-rotor/include/rotor/actor_base.h
• /home/b/development/cpp/cpp-rotor/include/rotor/supervisor.h