#include <userver/storages/postgres/dist_lock_component_base.hpp>
Base class for postgres-based distlock worker components.
A component that implements a distlock with lock in Postgres. Inherit from DistLockComponentBase and implement DoWork(). Lock options are configured in static config.
The class must be used for infinite loop jobs. If you want a distributed periodic, you should look at locked_periodiccomponents::PgLockedPeriodic.
name | Description | Default value |
---|---|---|
cluster | postgres cluster name | – |
table | table name to store distlocks | – |
lockname | name of the lock | – |
lock-ttl | TTL of the lock; must be at least as long as the duration between subsequent cancellation checks, otherwise brain split is possible | – |
pg-timeout | timeout, must be less than lock-ttl/2 | – |
restart-delay | how much time to wait after failed task restart | 100ms |
autostart | if true, start automatically after component load | false |
task-processor | the name of the TaskProcessor for running DoWork | main-task-processor |
testsuite-support | Enable testsuite support | false |
You have to create a SQL table for distlocks. An example of the migration script is as following:
Definition at line 74 of file dist_lock_component_base.hpp.
Public Member Functions | |
DistLockComponentBase (const components::ComponentConfig &, const components::ComponentContext &) | |
dist_lock::DistLockedWorker & | GetWorker () |
Public Member Functions inherited from components::LoggableComponentBase | |
LoggableComponentBase (const ComponentConfig &, const ComponentContext &) | |
LoggableComponentBase (LoggableComponentBase &&)=delete | |
LoggableComponentBase (const LoggableComponentBase &)=delete | |
~LoggableComponentBase () override=default | |
ComponentHealth | GetComponentHealth () const override |
void | OnLoadingCancelled () override |
void | OnAllComponentsLoaded () override |
void | OnAllComponentsAreStopping () override |
Static Public Member Functions | |
static yaml_config::Schema | GetStaticConfigSchema () |
Static Public Member Functions inherited from components::LoggableComponentBase | |
static yaml_config::Schema | GetStaticConfigSchema () |
Protected Member Functions | |
virtual void | DoWork ()=0 |
virtual void | DoWorkTestsuite () |
Override this function to provide custom testsuite handler. | |
void | AutostartDistLock () |
Must be called in ctr. | |
void | StopDistLock () |
Must be called in dtr. | |
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protectedpure virtual |
Override this function with anything that must be done under the pg lock.
DoWork
must honour task cancellation and stop ASAP when it is cancelled, otherwise brain split is possible (IOW, two different users do work assuming both of them hold the lock, which is not true).
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inlineprotectedvirtual |
Override this function to provide custom testsuite handler.
Definition at line 118 of file dist_lock_component_base.hpp.