DaemonMessaging.h File Reference

Include dependency graph for DaemonMessaging.h:

Functions
template<class Message, class Handler>
bool	mqss::qrmci::receiveNext (CommunicationHandler &comms, const std::string &queueName, std::chrono::milliseconds timeout, const std::atomic< bool > &terminationFlag, Handler &&handle)
	Receive one message from a queue and hand it to handle.
template<class Message, class Handler>
bool	mqss::qrmci::drainQueue (CommunicationHandler &comms, const std::string &queueName, const std::atomic< bool > &terminationFlag, Handler &&handle)
	Receive from a queue until it is empty or the broker fails, handing every message to handle.
template<class Message>
void	mqss::qrmci::send (CommunicationHandler &comms, const Message &message, const std::string &queueName)
	Send a message, logging rather than propagating a failure.
void	mqss::qrmci::sendFailure (CommunicationHandler &comms, const mqss::QuantumTask &task, const Error &failure, std::string_view stage)
	Tell a task's submitter that the task failed, and log why.
void	mqss::qrmci::sendResult (CommunicationHandler &comms, const mqss::QuantumTask &task, const mqss::QuantumResult &result)
	Send a task's result to its own result destination, and log it.

Detailed Description

The queue I/O every QRM&CI daemon work loop shares: receiving and draining a queue, and the best-effort sends a work loop makes, including telling a task's submitter how it ended.

Definition in file DaemonMessaging.h.

Function Documentation

drainQueue()

template<class Message, class Handler>

bool mqss::qrmci::drainQueue	(	CommunicationHandler &	comms,
		const std::string &	queueName,
		const std::atomic< bool > &	terminationFlag,
		Handler &&	handle )

Receive from a queue until it is empty or the broker fails, handing every message to handle.

Template Parameters

Message	The message type to receive.
Handler	Callable as handle(Message &&), invoked once per message.

Parameters

comms	The handler to receive through.
queueName	The queue to drain.
terminationFlag	Consulted before each poll; see receiveNext()'s own documentation.
handle	Invoked with each received message.

Returns

True if at least one message was handled.

Definition at line 73 of file DaemonMessaging.h.

receiveNext()

template<class Message, class Handler>

bool mqss::qrmci::receiveNext	(	CommunicationHandler &	comms,
		const std::string &	queueName,
		std::chrono::milliseconds	timeout,
		const std::atomic< bool > &	terminationFlag,
		Handler &&	handle )

Receive one message from a queue and hand it to handle.

Neither an empty queue nor a broker failure is fatal to a work loop: both simply mean there is nothing to do this turn, the second after a warning.

Template Parameters

Message	The message type to receive.
Handler	Callable as handle(Message &&).

Parameters

comms	The handler to receive through.
queueName	The queue to consume from.
timeout	How long to wait; 0ms polls once and returns immediately.
terminationFlag	Consulted before the receive attempt (and between polls of an indefinite wait), so a shutdown interrupts the wait rather than outliving it. The caller supplies this explicitly – a daemon passes its own process-wide flag; a test or short-lived tool that never shuts down can pass one that is never set.
handle	Invoked with the received message, if one arrived.

Returns

True if a message was received and handed to handle.

Definition at line 46 of file DaemonMessaging.h.

send()

template<class Message>

void mqss::qrmci::send	(	CommunicationHandler &	comms,
		const Message &	message,
		const std::string &	queueName )

Send a message, logging rather than propagating a failure.

Every send a running daemon makes is best-effort: a broker that rejects a message must not cost the daemon its in-flight work, so a failure is logged and the loop carries on.

Template Parameters

Message

The message type to send.

Parameters

comms	The handler to send through.
message	The message to send.
queueName	The queue to send it to.

Definition at line 96 of file DaemonMessaging.h.

sendFailure()

void mqss::qrmci::sendFailure ( CommunicationHandler & comms, const mqss::QuantumTask & task, const Error & failure, std::string_view stage )

inline

Tell a task's submitter that the task failed, and log why.

Parameters

comms	The handler to send through.
task	The task that failed.
failure	The failure to report, carried into the cancellation message the submitter receives.
stage	What the daemon was doing, e.g. could not be scheduled.

Definition at line 109 of file DaemonMessaging.h.

sendResult()

void mqss::qrmci::sendResult ( CommunicationHandler & comms, const mqss::QuantumTask & task, const mqss::QuantumResult & result )

inline

Send a task's result to its own result destination, and log it.

Parameters

comms	The handler to send through.
task	The task the result belongs to.
result	The result to send.

Definition at line 122 of file DaemonMessaging.h.