ErrorHandlers Namespace Reference

Functions
FunctionState *	logAndContinue (QGCStateMachine *machine, const QString &stateName, QAbstractState *nextState, const QString &message)
FunctionState *	logAndStop (QGCStateMachine *machine, const QString &stateName, const QString &message)
std::function< int(int)>	exponentialBackoff (int initialDelayMsecs, double multiplier, int maxDelayMsecs)
std::function< int(int)>	linearBackoff (int initialDelayMsecs, int incrementMsecs, int maxDelayMsecs)
std::function< int(int)>	constantDelay (int delayMsecs)
std::function< int(int)>	jitteredExponentialBackoff (int initialDelayMsecs, double multiplier, int maxDelayMsecs, double jitterFraction)

Detailed Description

Pre-built error handling utilities.

Provides common error handling patterns as ready-to-use functions and states.

Example usage:

// Log and continue to next state
machine.setGlobalErrorState(
    ErrorHandlers::logAndContinue(&machine, "ErrorLogged", nextState));
 
// Exponential backoff for retries
auto backoff = ErrorHandlers::exponentialBackoff(1000, 2.0, 30000);
int delay = backoff(attemptNumber);  // 1000, 2000, 4000, 8000, ...

Function Documentation

constantDelay()

std::function< int(int)> ErrorHandlers::constantDelay

(

int

delayMsecs

)

Create a constant delay calculator (same delay for all attempts)

Parameters

delayMsecs

Constant delay in milliseconds

Returns

Function that takes attempt number and returns constant delay

Definition at line 67 of file ErrorHandlers.cc.

exponentialBackoff()

std::function< int(int)> ErrorHandlers::exponentialBackoff	(	int	initialDelayMsecs,
		double	multiplier = 2.0,
		int	maxDelayMsecs = 60000
	)

Create an exponential backoff delay calculator

Parameters

initialDelayMsecs	Initial delay in milliseconds
multiplier	Multiplier for each subsequent attempt (default 2.0)
maxDelayMsecs	Maximum delay cap

Returns

Function that takes attempt number (1-based) and returns delay

Definition at line 44 of file ErrorHandlers.cc.

jitteredExponentialBackoff()

std::function< int(int)> ErrorHandlers::jitteredExponentialBackoff	(	int	initialDelayMsecs,
		double	multiplier = 2.0,
		int	maxDelayMsecs = 60000,
		double	jitterFraction = 0.25
	)

Create a jittered exponential backoff (adds randomness to prevent thundering herd)

Parameters

initialDelayMsecs	Initial delay in milliseconds
multiplier	Multiplier for each subsequent attempt
maxDelayMsecs	Maximum delay cap
jitterFraction	Fraction of delay to add as random jitter (0.0-1.0)

Returns

Function that takes attempt number and returns jittered delay

Definition at line 74 of file ErrorHandlers.cc.

linearBackoff()

std::function< int(int)> ErrorHandlers::linearBackoff	(	int	initialDelayMsecs,
		int	incrementMsecs,
		int	maxDelayMsecs = 60000
	)

Create a linear backoff delay calculator

Parameters

initialDelayMsecs	Initial delay in milliseconds
incrementMsecs	Amount to add for each subsequent attempt
maxDelayMsecs	Maximum delay cap

Returns

Function that takes attempt number (1-based) and returns delay

Definition at line 57 of file ErrorHandlers.cc.

logAndContinue()

FunctionState * ErrorHandlers::logAndContinue	(	QGCStateMachine *	machine,
		const QString &	stateName,
		QAbstractState *	nextState,
		const QString &	message = QString()
	)

Create a state that logs the error and transitions to the next state

Parameters

machine	Parent state machine
stateName	Name for the error logging state
nextState	State to transition to after logging
message	Optional custom message to log

Definition at line 10 of file ErrorHandlers.cc.

References QGCAbstractState::advance().

logAndStop()

FunctionState * ErrorHandlers::logAndStop	(	QGCStateMachine *	machine,
		const QString &	stateName,
		const QString &	message = QString()
	)

Create a state that logs the error and stops the machine

Parameters

machine	Parent state machine
stateName	Name for the error state
message	Optional custom message to log

Definition at line 28 of file ErrorHandlers.cc.