Inheritance diagram for rclcpp::Client< ServiceT >:

Collaboration diagram for rclcpp::Client< ServiceT >:

Classes
struct	FutureAndRequestId
	A convenient Client::Future and request id pair. More...

struct	SharedFutureAndRequestId
	A convenient Client::SharedFuture and request id pair. More...

struct	SharedFutureWithRequestAndRequestId
	A convenient Client::SharedFutureWithRequest and request id pair. More...

Public Types
using	Request = typename ServiceT::Request

using	Response = typename ServiceT::Response

using	SharedRequest = typename ServiceT::Request::SharedPtr

using	SharedResponse = typename ServiceT::Response::SharedPtr

using	Promise = std::promise< SharedResponse >

using	PromiseWithRequest = std::promise< std::pair< SharedRequest, SharedResponse > >

using	SharedPromise = std::shared_ptr< Promise >

using	SharedPromiseWithRequest = std::shared_ptr< PromiseWithRequest >

using	Future = std::future< SharedResponse >

using	SharedFuture = std::shared_future< SharedResponse >

using	SharedFutureWithRequest = std::shared_future< std::pair< SharedRequest, SharedResponse > >

using	CallbackType = std::function< void(SharedFuture)>

using	CallbackWithRequestType = std::function< void(SharedFutureWithRequest)>

Public Member Functions
	Client (rclcpp::node_interfaces::NodeBaseInterface *node_base, rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph, const std::string &service_name, rcl_client_options_t &client_options)
	Default constructor. More...

bool	take_response (typename ServiceT::Response &response_out, rmw_request_id_t &request_header_out)
	Take the next response for this client. More...

std::shared_ptr< void >	create_response () override
	Create a shared pointer with the response type. More...

std::shared_ptr< rmw_request_id_t >	create_request_header () override
	Create a shared pointer with a rmw_request_id_t. More...

void	handle_response (std::shared_ptr< rmw_request_id_t > request_header, std::shared_ptr< void > response) override
	Handle a server response. More...

FutureAndRequestId	async_send_request (SharedRequest request)
	Send a request to the service server. More...

template<typename CallbackT , typename std::enable_if< rclcpp::function_traits::same_arguments< CallbackT, CallbackType >::value >::type * = nullptr>
SharedFutureAndRequestId	async_send_request (SharedRequest request, CallbackT &&cb)
	Send a request to the service server and schedule a callback in the executor. More...

template<typename CallbackT , typename std::enable_if< rclcpp::function_traits::same_arguments< CallbackT, CallbackWithRequestType >::value >::type * = nullptr>
SharedFutureWithRequestAndRequestId	async_send_request (SharedRequest request, CallbackT &&cb)
	Send a request to the service server and schedule a callback in the executor. More...

bool	remove_pending_request (int64_t request_id)
	Cleanup a pending request. More...

bool	remove_pending_request (const FutureAndRequestId &future)
	Cleanup a pending request. More...

bool	remove_pending_request (const SharedFutureAndRequestId &future)
	Cleanup a pending request. More...

bool	remove_pending_request (const SharedFutureWithRequestAndRequestId &future)
	Cleanup a pending request. More...

size_t	prune_pending_requests ()
	Clean all pending requests. More...

template<typename AllocatorT = std::allocator<int64_t>>
size_t	prune_requests_older_than (std::chrono::time_point< std::chrono::system_clock > time_point, std::vector< int64_t, AllocatorT > *pruned_requests=nullptr)
	Clean all pending requests older than a time_point. More...

Public Member Functions inherited from rclcpp::ClientBase
RCLCPP_PUBLIC	ClientBase (rclcpp::node_interfaces::NodeBaseInterface *node_base, rclcpp::node_interfaces::NodeGraphInterface::SharedPtr node_graph)

RCLCPP_PUBLIC bool	take_type_erased_response (void *response_out, rmw_request_id_t &request_header_out)
	Take the next response for this client as a type erased pointer. More...

RCLCPP_PUBLIC const char *	get_service_name () const
	Return the name of the service. More...

RCLCPP_PUBLIC std::shared_ptr< rcl_client_t >	get_client_handle ()
	Return the rcl_client_t client handle in a std::shared_ptr. More...

RCLCPP_PUBLIC std::shared_ptr< const rcl_client_t >	get_client_handle () const
	Return the rcl_client_t client handle in a std::shared_ptr. More...

RCLCPP_PUBLIC bool	service_is_ready () const
	Return if the service is ready. More...

template<typename RepT = int64_t, typename RatioT = std::milli>
bool	wait_for_service (std::chrono::duration< RepT, RatioT > timeout=std::chrono::duration< RepT, RatioT >(-1))
	Wait for a service to be ready. More...

RCLCPP_PUBLIC bool	exchange_in_use_by_wait_set_state (bool in_use_state)
	Exchange the "in use by wait set" state for this client. More...

RCLCPP_PUBLIC rclcpp::QoS	get_request_publisher_actual_qos () const
	Get the actual request publsher QoS settings, after the defaults have been determined. More...

RCLCPP_PUBLIC rclcpp::QoS	get_response_subscription_actual_qos () const
	Get the actual response subscription QoS settings, after the defaults have been determined. More...

void	set_on_new_response_callback (std::function< void(size_t)> callback)
	Set a callback to be called when each new response is received. More...

void	clear_on_new_response_callback ()
	Unset the callback registered for new responses, if any.

Protected Types
using	CallbackTypeValueVariant = std::tuple< CallbackType, SharedFuture, Promise >

using	CallbackWithRequestTypeValueVariant = std::tuple< CallbackWithRequestType, SharedRequest, SharedFutureWithRequest, PromiseWithRequest >

using	CallbackInfoVariant = std::variant< std::promise< SharedResponse >, CallbackTypeValueVariant, CallbackWithRequestTypeValueVariant >

Protected Member Functions
int64_t	async_send_request_impl (const Request &request, CallbackInfoVariant value)

std::optional< CallbackInfoVariant >	get_and_erase_pending_request (int64_t request_number)

Protected Member Functions inherited from rclcpp::ClientBase
RCLCPP_PUBLIC bool	wait_for_service_nanoseconds (std::chrono::nanoseconds timeout)

RCLCPP_PUBLIC rcl_node_t *	get_rcl_node_handle ()

RCLCPP_PUBLIC const rcl_node_t *	get_rcl_node_handle () const

RCLCPP_PUBLIC void	set_on_new_response_callback (rcl_event_callback_t callback, const void *user_data)

Protected Attributes
std::unordered_map< int64_t, std::pair< std::chrono::time_point< std::chrono::system_clock >, CallbackInfoVariant > >	pending_requests_

std::mutex	pending_requests_mutex_

Protected Attributes inherited from rclcpp::ClientBase
rclcpp::node_interfaces::NodeGraphInterface::WeakPtr	node_graph_

std::shared_ptr< rcl_node_t >	node_handle_

std::shared_ptr< rclcpp::Context >	context_

rclcpp::Logger	node_logger_

std::shared_ptr< rcl_client_t >	client_handle_

std::atomic< bool >	in_use_by_wait_set_ {false}

std::recursive_mutex	callback_mutex_

std::function< void(size_t)>	on_new_response_callback_ {nullptr}

Detailed Description

template<typename ServiceT>
class rclcpp::Client< ServiceT >

Definition at line 371 of file client.hpp.

Constructor & Destructor Documentation

◆ Client()

template<typename ServiceT >

rclcpp::Client< ServiceT >::Client	(	rclcpp::node_interfaces::NodeBaseInterface *	node_base,
		rclcpp::node_interfaces::NodeGraphInterface::SharedPtr	node_graph,
		const std::string &	service_name,
		rcl_client_options_t &	client_options
	)

inline

Default constructor.

The constructor for a Client is almost never called directly. Instead, clients should be instantiated through the function rclcpp::create_client().

Parameters

[in]	node_base	NodeBaseInterface pointer that is used in part of the setup.
[in]	node_graph	The node graph interface of the corresponding node.
[in]	service_name	Name of the topic to publish to.
[in]	client_options	options for the subscription.

Definition at line 464 of file client.hpp.

References rclcpp::expand_topic_or_service_name(), rclcpp::ClientBase::get_client_handle(), rcl_client_init(), rcl_node_get_name(), rcl_node_get_namespace(), RCL_RET_OK, and RCL_RET_SERVICE_NAME_INVALID.

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Member Function Documentation

◆ async_send_request() [1/3]

template<typename ServiceT >

FutureAndRequestId rclcpp::Client< ServiceT >::async_send_request ( SharedRequest request )

inline

Send a request to the service server.

This method returns a FutureAndRequestId instance that can be passed to Executor::spin_until_future_complete() to wait until it has been completed.

If the future never completes, e.g. the call to Executor::spin_until_future_complete() times out, Client::remove_pending_request() must be called to clean the client internal state. Not doing so will make the Client instance to use more memory each time a response is not received from the service server.

auto future = client->async_send_request(my_request);
if (
  rclcpp::FutureReturnCode::TIMEOUT ==
  executor->spin_until_future_complete(future, timeout))
{
  client->remove_pending_request(future);
  // handle timeout
} else {
  handle_response(future.get());
}

Parameters

[in] request request to be send.

Returns: a FutureAndRequestId instance.

Definition at line 608 of file client.hpp.

◆ async_send_request() [2/3]

template<typename ServiceT >

template<typename CallbackT , typename std::enable_if< rclcpp::function_traits::same_arguments< CallbackT, CallbackType >::value >::type * = nullptr>

SharedFutureAndRequestId rclcpp::Client< ServiceT >::async_send_request	(	SharedRequest	request,
		CallbackT &&	cb
	)

inline

Send a request to the service server and schedule a callback in the executor.

Similar to the previous overload, but a callback will automatically be called when a response is received.

If the callback is never called, because we never got a reply for the service server, remove_pending_request() has to be called with the returned request id or prune_pending_requests(). Not doing so will make the Client instance use more memory each time a response is not received from the service server. In this case, it's convenient to setup a timer to cleanup the pending requests. See for example the examples_rclcpp_async_client package in https://github.com/ros2/examples.

Parameters

[in]	request	request to be send.
[in]	cb	callback that will be called when we get a response for this request.

Returns: the request id representing the request just sent.

Definition at line 643 of file client.hpp.

◆ async_send_request() [3/3]

template<typename ServiceT >

template<typename CallbackT , typename std::enable_if< rclcpp::function_traits::same_arguments< CallbackT, CallbackWithRequestType >::value >::type * = nullptr>

SharedFutureWithRequestAndRequestId rclcpp::Client< ServiceT >::async_send_request	(	SharedRequest	request,
		CallbackT &&	cb
	)

inline

Send a request to the service server and schedule a callback in the executor.

Similar to the previous method, but you can get both the request and response in the callback.

Parameters

[in]	request	request to be send.
[in]	cb	callback that will be called when we get a response for this request.

Returns: the request id representing the request just sent.

Definition at line 674 of file client.hpp.

◆ create_request_header()

template<typename ServiceT >

std::shared_ptr<rmw_request_id_t> rclcpp::Client< ServiceT >::create_request_header ( )

inlineoverridevirtual

Create a shared pointer with a rmw_request_id_t.

Returns: shared pointer with a rmw_request_id_t

Implements rclcpp::ClientBase.

Definition at line 533 of file client.hpp.

◆ create_response()

template<typename ServiceT >

std::shared_ptr<void> rclcpp::Client< ServiceT >::create_response ( )

inlineoverridevirtual

Create a shared pointer with the response type.

Returns: shared pointer with the response type

Implements rclcpp::ClientBase.

Definition at line 523 of file client.hpp.

◆ handle_response()

template<typename ServiceT >

void rclcpp::Client< ServiceT >::handle_response	(	std::shared_ptr< rmw_request_id_t >	request_header,
		std::shared_ptr< void >	response
	)

inlineoverridevirtual

Handle a server response.

Parameters

[in]	request_header	used to check if the secuence number is valid
[in]	response	message with the server response

Implements rclcpp::ClientBase.

Definition at line 546 of file client.hpp.

◆ prune_pending_requests()

template<typename ServiceT >

size_t rclcpp::Client< ServiceT >::prune_pending_requests ( )

inline

Clean all pending requests.

Returns: number of pending requests that were removed.

Definition at line 747 of file client.hpp.

◆ prune_requests_older_than()

template<typename ServiceT >

template<typename AllocatorT = std::allocator<int64_t>>

size_t rclcpp::Client< ServiceT >::prune_requests_older_than	(	std::chrono::time_point< std::chrono::system_clock >	time_point,
		std::vector< int64_t, AllocatorT > *	pruned_requests = `nullptr`
	)

inline

Clean all pending requests older than a time_point.

Parameters

[in]	time_point	Requests that were sent before this point are going to be removed.
[in,out]	pruned_requests	Removed requests id will be pushed to the vector if a pointer is provided.

Returns: number of pending requests that were removed.

Definition at line 764 of file client.hpp.

◆ remove_pending_request() [1/4]

template<typename ServiceT >

bool rclcpp::Client< ServiceT >::remove_pending_request ( const FutureAndRequestId & future )

inline

Cleanup a pending request.

Convenient overload, same as:

Client::remove_pending_request(this, future.request_id).

Definition at line 713 of file client.hpp.

References rclcpp::Client< ServiceT >::remove_pending_request().

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◆ remove_pending_request() [2/4]

template<typename ServiceT >

bool rclcpp::Client< ServiceT >::remove_pending_request ( const SharedFutureAndRequestId & future )

inline

Cleanup a pending request.

Convenient overload, same as:

Client::remove_pending_request(this, future.request_id).

Definition at line 725 of file client.hpp.

References rclcpp::Client< ServiceT >::remove_pending_request().

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◆ remove_pending_request() [3/4]

template<typename ServiceT >

bool rclcpp::Client< ServiceT >::remove_pending_request ( const SharedFutureWithRequestAndRequestId & future )

inline

Cleanup a pending request.

Convenient overload, same as:

Client::remove_pending_request(this, future.request_id).

Definition at line 737 of file client.hpp.

References rclcpp::Client< ServiceT >::remove_pending_request().

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◆ remove_pending_request() [4/4]

template<typename ServiceT >

bool rclcpp::Client< ServiceT >::remove_pending_request ( int64_t request_id )

inline

Cleanup a pending request.

This notifies the client that we have waited long enough for a response from the server to come, we have given up and we are not waiting for a response anymore.

Not calling this will make the client start using more memory for each request that never got a reply from the server.

Parameters

[in] request_id request id returned by async_send_request().

Returns: true when a pending request was removed, false if not (e.g. a response was received).

Definition at line 700 of file client.hpp.

Referenced by rclcpp::Client< ServiceT >::remove_pending_request().

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◆ take_response()

template<typename ServiceT >

bool rclcpp::Client< ServiceT >::take_response	(	typename ServiceT::Response &	response_out,
		rmw_request_id_t &	request_header_out
	)

inline

Take the next response for this client.

See also: ClientBase::take_type_erased_response().

Parameters

[out]	response_out	The reference to a Service Response into which the middleware will copy the response being taken.
[out]	request_header_out	The request header to be filled by the middleware when taking, and which can be used to associte the response to a specific request.

Returns: true if the response was taken, otherwise false.

Exceptions

rclcpp::exceptions::RCLError based exceptions if the underlying rcl function fail.

Definition at line 513 of file client.hpp.

References rclcpp::ClientBase::take_type_erased_response().

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The documentation for this class was generated from the following file:

rclcpp/include/rclcpp/client.hpp

Classes

Public Types

Public Member Functions

Protected Types

Protected Member Functions

Protected Attributes

Detailed Description

template<typename ServiceT> class rclcpp::Client< ServiceT >

Constructor & Destructor Documentation

◆ Client()

Member Function Documentation

◆ async_send_request() [1/3]

◆ async_send_request() [2/3]

◆ async_send_request() [3/3]

◆ create_request_header()

◆ create_response()

◆ handle_response()

◆ prune_pending_requests()

◆ prune_requests_older_than()

◆ remove_pending_request() [1/4]

◆ remove_pending_request() [2/4]

◆ remove_pending_request() [3/4]

◆ remove_pending_request() [4/4]

◆ take_response()

template<typename ServiceT>
class rclcpp::Client< ServiceT >