storages::mongo::DistLockStrategy Class Reference

#include <userver/storages/mongo/dist_lock_strategy.hpp>

Detailed Description

Strategy for MongoDB-based distributed locking.

Definition at line 17 of file dist_lock_strategy.hpp.

Inheritance diagram for storages::mongo::DistLockStrategy:

Public Member Functions
	DistLockStrategy (Collection collection, std::string lock_name)
	Targets a distributed lock in a specified collection as a host.
	DistLockStrategy (Collection collection, std::string lock_name, std::string owner)
void	Acquire (std::chrono::milliseconds lock_ttl, const std::string &locker_id) override
void	Prolong (std::chrono::milliseconds lock_ttl, const std::string &locker_id) override
void	Release (const std::string &locker_id) override

Member Function Documentation

Acquire()

void storages::mongo::DistLockStrategy::Acquire ( std::chrono::milliseconds lock_ttl, const std::string & locker_id )

overridevirtual

Acquires the distributed lock.

Parameters

lock_ttl	The duration for which the lock must be held.
locker_id	Globally unique ID of the locking entity.

Exceptions

LockIsAcquiredByAnotherHostError	when the lock is busy
anything	else when the locking fails, strategy is responsible for cleanup, Release won't be invoked.

Implements dist_lock::DistLockStrategyBase.

Prolong()

void storages::mongo::DistLockStrategy::Prolong ( std::chrono::milliseconds lock_ttl, const std::string & locker_id )

overridevirtual

Prolongs (refreshes the TTL of) a lock already held by locker_id.

Called instead of Acquire() on every refresh while the lock is held, so backends may implement a cheaper query than the full Acquire().

Parameters

lock_ttl	The new duration for which the lock must be held.
locker_id	Globally unique ID of the locking entity, must be the same as in Acquire().

Exceptions

LockIsAcquiredByAnotherHostException	when the lock is no longer held by locker_id (ownership was lost)
anything	else when the prolongation fails, strategy is responsible for cleanup, Release won't be invoked.

Note

The default implementation simply calls Acquire(), preserving the legacy behaviour for strategies that do not override it.

Reimplemented from dist_lock::DistLockStrategyBase.

Release()

void storages::mongo::DistLockStrategy::Release ( const std::string & locker_id )

overridevirtual

Releases the lock.

Parameters

locker_id

Globally unique ID of the locking entity, must be the same as in Acquire().

Note

Exceptions are ignored.

Implements dist_lock::DistLockStrategyBase.

---

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

• userver/storages/mongo/dist_lock_strategy.hpp