mongo::FailPoint Class Reference

A simple thread-safe fail point implementation that can be activated and deactivated, as well as embed temporary data into it. More...

#include <fail_point.h>

Public Member Functions
bool	shouldFail ()
	Note: This is not side-effect free - it can change the state to OFF after calling. More...
RetCode	shouldFailOpenBlock ()
	Checks whether fail point is active and increments the reference counter without decrementing it. More...
void	shouldFailCloseBlock ()
	Decrements the reference counter. More...
void	setMode (Mode mode, ValType val=0, const BSONObj &extra=BSONObj())
	Changes the settings of this fail point. More...
BSONObj	toBSON () const

Detailed Description

A simple thread-safe fail point implementation that can be activated and deactivated, as well as embed temporary data into it.

The fail point has a static instance, which is represented by a FailPoint object, and dynamic instance, which are all the threads in between shouldFailOpenBlock and shouldFailCloseBlock.

Sample use: // Declared somewhere: FailPoint makeBadThingsHappen;

// Somewhere in the code return false || MONGO_FAIL_POINT(makeBadThingsHappen);

or

// Somewhere in the code MONGO_FAIL_POINT_BLOCK(makeBadThingsHappen, blockMakeBadThingsHappen) { const BSONObj& data = blockMakeBadThingsHappen.getData(); // Do something }

Invariants:

1. Always refer to _fpInfo first to check if failPoint is active or not before entering fail point or modifying fail point.
2. Client visible fail point states are read-only when active.

Member Function Documentation

void mongo::FailPoint::setMode	(	Mode	mode,
		ValType	val = 0,
		const BSONObj &	extra = BSONObj()
	)

Changes the settings of this fail point.

This will turn off the fail point and waits for all dynamic instances referencing this fail point to go away before actually modifying the settings.

Parameters

mode	the new mode for this fail point.
val	the value that can have different usage depending on the mode: - off, alwaysOn: ignored - random: - nTimes: the number of times this fail point will be active when #shouldFail or #shouldFailOpenBlock is called.
extra	arbitrary BSON object that can be stored to this fail point that can be referenced afterwards with #getData. Defaults to an empty document.

bool mongo::FailPoint::shouldFail ( )

inline

Note: This is not side-effect free - it can change the state to OFF after calling.

Returns

true if fail point is active.

void mongo::FailPoint::shouldFailCloseBlock

(

)

Decrements the reference counter.

See also

shouldFailOpenBlock

RetCode mongo::FailPoint::shouldFailOpenBlock ( )

inline

Checks whether fail point is active and increments the reference counter without decrementing it.

Must call shouldFailCloseBlock afterwards when the return value is not fastOff. Otherwise, this will remain read-only forever.

Returns

slowOn if fail point is active.

BSONObj mongo::FailPoint::toBSON

(

)

const

Returns

a BSON object showing the current mode and data stored.

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

• src/mongo/util/fail_point.h