#include <userver/ydb/dist_lock/component_base.hpp>
Base class for YDB-based distlock worker components.
A component that implements a distlock with lock in YDB. Inherit from DistLockComponentBase and implement DoWork(). Lock options are configured in static config.
The class must be used for infinite loop jobs.
name | Description | Default value |
---|---|---|
semaphore-name | name of the semaphore within the coordination node | – |
database-settings.dbname | the key of the database within ydb component (NOT the actual database path) | – |
database-settings.coordination-node | name of the coordination node within the database | – |
initial-setup | if true, then create the coordination node and the semaphore unless they already exist | true |
task-processor | the name of the TaskProcessor for running DoWork | main-task-processor |
node-settings.session-grace-period | the time after which the lock will be given to another host after a network failure | 10s |
session-timeout | for how long we will try to restore session after a network failure before dropping it | 5s |
restart-session-delay | backoff before attempting to reconnect session after it returns "permanent failure" | 1s |
acquire-interval | backoff before repeating a failed Acquire call | 100ms |
restart-delay | backoff before calling DoWork again after it returns or throws | 100ms |
cancel-task-time-limit | time, within which a cancelled DoWork is expected to finish | 5s |
Definition at line 55 of file component_base.hpp.
Public Member Functions | |
DistLockComponentBase (const components::ComponentConfig &, const components::ComponentContext &) | |
bool | OwnsLock () const noexcept |
Checks if the the current service instance owns the lock. | |
ComponentHealth | GetComponentHealth () const override |
void | OnLoadingCancelled () override |
void | OnAllComponentsLoaded () override |
void | OnAllComponentsAreStopping () override |
Static Public Member Functions | |
static yaml_config::Schema | GetStaticConfigSchema () |
Protected Types | |
using | LoggableComponentBase = ComponentBase |
Legacy alias, use ComponentBase instead. | |
Protected Member Functions | |
virtual void | DoWork ()=0 |
virtual void | DoWorkTestsuite () |
void | Start () |
Must be called at the end of the constructor of the derived component. | |
void | Stop () noexcept |
Must be called in the destructor of the derived component. | |
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protectedinherited |
Legacy alias, use ComponentBase instead.
Definition at line 69 of file component_base.hpp.
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protectedpure virtual |
Override this function with anything that must be done under the 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).restart-delay
the lock is attempted to be re-acquired (but by that time another host likely acquires the lock).
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inlineprotectedvirtual |
Override this function to provide a custom testsuite handler, e.g. one that does not contain a "while not cancelled" loop. Calls DoWork
by default.
In testsuite runs, the normal DoWork execution disabled by default. There is an API to call DoWorkTestsuite from testsuite, imitating waiting until DoWork runs:
Definition at line 100 of file component_base.hpp.
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inlineoverridevirtualinherited |
Override this function to inform the world of the state of your component.
Reimplemented from components::RawComponentBase.
Definition at line 35 of file component_base.hpp.
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inlineoverridevirtualinherited |
Component may use this function to stop doing work before the stop of the components that depend on it.
Base components may override it and make final
to do some work before the derived object constructor is called. Don't use it otherwise.
Reimplemented from components::RawComponentBase.
Reimplemented in urabbitmq::ConsumerComponentBase, and components::Server.
Definition at line 60 of file component_base.hpp.
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inlineoverridevirtualinherited |
Component may use this function to finalize registration of other components that depend on it (for example, handler components register in server component, and the latter uses OnAllComponentsLoaded() to start processing requests).
Base components may override it and make final
to do some work after the derived object constructor is called. Don't use it otherwise.
Reimplemented from components::RawComponentBase.
Reimplemented in urabbitmq::ConsumerComponentBase, components::Server, and server::handlers::Ping.
Definition at line 53 of file component_base.hpp.
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inlineoverridevirtualinherited |
Called once if the creation of any other component failed. If the current component expects some other component to take any action with the current component, this call is a signal that such action may never happen due to components loading was cancelled. Application components might not want to override it.
Reimplemented from components::RawComponentBase.
Definition at line 44 of file component_base.hpp.
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noexcept |
Checks if the the current service instance owns the lock.
Useful for: