#include <userver/dynamic_config/updater/component.hpp>

Detailed Description

Component that does a periodic update of runtime configs.

Note that the service with dynamic config update component and without configs cache requires successful update to start. See dynamic_config_fallback for details and explanation.

Optional update event deduplication

Config update types to deduplicate. If enabled, JSON of the whole config is compared to the previous one; if same, no config update event is sent to the subscribers of dynamic_config::Source (OnConfigUpdate functions).

deduplicate-update-types static config option specifies the update types of the config cache, for which event deduplication should be performed. Possible values:

none (the default)
only-full
only-incremental
full-and-incremental

Full updates will always send an event unless deduplicated. Incremental updates may send an extra event for some config service implementations.

Note: This is not a silver bullet against extra events, because the events will be sent to every dynamic config subscriber if any part of the config has updated, not if the interesting part has updated.

Static options:

Name	Description	Default value
updates-sink	name of the component derived from components::DynamicConfigUpdatesSinkBase to be used for storing received updates	dynamic-config
store-enabled	store the retrieved values into the updates sink determined by the `updates-sink` option	true
load-only-my-values	request from the client only the values used by this service	true
deduplicate-update-types	update types for best-effort update event deduplication, see above	`full-and-incremental`

See also the options for components::CachingComponentBase.

Static configuration example:

# yaml
    dynamic-config-client-updater:
      store-enabled: true
      load-only-my-values: true
 
      # options from components::CachingComponentBase
      update-types: full-and-incremental
      update-interval: 5s
      update-jitter: 2s
      full-update-interval: 5m
      first-update-fail-ok: true
      config-settings: false
      additional-cleanup-interval: 5m

Definition at line 74 of file component.hpp.

Inheritance diagram for components::DynamicConfigClientUpdater:

Public Types
using	DataType

Public Member Functions
	DynamicConfigClientUpdater (const ComponentConfig &, const ComponentContext &)

dynamic_config::AdditionalKeysToken	SetAdditionalKeys (std::vector< std::string > keys)

utils::SharedReadablePtr< dynamic_config::DocsMap >	Get () const

utils::SharedReadablePtr< dynamic_config::DocsMap >	GetUnsafe () const

concurrent::AsyncEventSubscriberScope	UpdateAndListen (Class obj, std::string name, void(Class::func)(const std::shared_ptr< const dynamic_config::DocsMap > &))

concurrent::AsyncEventChannel< const std::shared_ptr< const dynamic_config::DocsMap > & > &	GetEventChannel ()

ComponentHealth	GetComponentHealth () const override

void	OnLoadingCancelled () override

void	OnAllComponentsAreStopping () override

Static Public Member Functions
static yaml_config::Schema	GetStaticConfigSchema ()

Static Public Attributes
static constexpr std::string_view	kName = "dynamic-config-client-updater"
	The default name of components::DynamicConfigClientUpdater.

Protected Types
using	LoggableComponentBase = ComponentBase
	Legacy alias, use ComponentBase instead.

enum class	Flag { kNone = 0 , kNoFirstUpdate = 1 << 0 }
	Periodic update flags. More...

Protected Member Functions
void	Set (std::unique_ptr< const dynamic_config::DocsMap > value_ptr)

void	Set (dynamic_config::DocsMap &&value)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

void	Emplace (Args &&... args)

void	Clear ()
	Clears the content of the cache by string a default constructed T.

virtual bool	MayReturnNull () const
	Whether Get is expected to return `nullptr`.

virtual void	PreAssignCheck (const dynamic_config::DocsMap old_value_ptr, const dynamic_config::DocsMap new_value_ptr) const
	If the option has-pre-assign-check is set true in static config, this function is called before assigning the new value to the cache.

void	InvalidateAsync (UpdateType update_type)
	Non-blocking forced cache update of specified type.

void	UpdateSyncDebug (UpdateType update_type)
	Forces a cache update of specified type.

const std::string &	Name () const

AllowedUpdateTypes	GetAllowedUpdateTypes () const
	Update types configured for the cache.

void	StartPeriodicUpdates (utils::Flags< Flag > flags={})
	Starts periodic updates.

void	StopPeriodicUpdates ()
	Stops periodic updates.

void	AssertPeriodicUpdateStarted ()

void	AssertPeriodicUpdateStopped ()

void	OnCacheModified ()


virtual void	WriteContents (dump::Writer &writer, const dynamic_config::DocsMap &contents) const

virtual std::unique_ptr< const dynamic_config::DocsMap >	ReadContents (dump::Reader &reader) const

Member Typedef Documentation

◆ DataType

using components::CachingComponentBase< dynamic_config::DocsMap >::DataType

inherited

Definition at line 162 of file caching_component_base.hpp.

◆ LoggableComponentBase

using components::ComponentBase::LoggableComponentBase = ComponentBase

protectedinherited

Legacy alias, use ComponentBase instead.

Definition at line 67 of file component_base.hpp.

Member Enumeration Documentation

◆ Flag

enum class cache::CacheUpdateTrait::Flag

strongprotectedinherited

Periodic update flags.

Enumerator

kNoFirstUpdate

Disable initial update on start.

Deprecated: Use first-update-fail-ok: true instead

Definition at line 61 of file cache_update_trait.hpp.

Member Function Documentation

◆ Clear()

void components::CachingComponentBase< dynamic_config::DocsMap >::Clear ( )

protectedinherited

Clears the content of the cache by string a default constructed T.

Definition at line 199 of file caching_component_base.hpp.

◆ Emplace()

void components::CachingComponentBase< dynamic_config::DocsMap >::Emplace ( Args &&... args )

protectedinherited

Definition at line 196 of file caching_component_base.hpp.

◆ Get()

utils::SharedReadablePtr< dynamic_config::DocsMap > components::CachingComponentBase< dynamic_config::DocsMap >::Get ( ) const

inherited

Returns: cache contents. May be nullptr if and only if MayReturnNull returns true.

Exceptions

cache::EmptyCacheError if the contents are nullptr, and MayReturnNull returns false (which is the default behavior).

Definition at line 168 of file caching_component_base.hpp.

◆ GetComponentHealth()

ComponentHealth components::ComponentBase::GetComponentHealth ( ) const

inlineoverridevirtualinherited

Override this function to inform the world of the state of your component.

Warning: The function is called concurrently from multiple threads.

Reimplemented from components::RawComponentBase.

Reimplemented in server::handlers::Restart.

Definition at line 35 of file component_base.hpp.

◆ GetEventChannel()

concurrent::AsyncEventChannel< const std::shared_ptr< const dynamic_config::DocsMap > & > & components::CachingComponentBase< dynamic_config::DocsMap >::GetEventChannel ( )

inherited

Definition at line 179 of file caching_component_base.hpp.

◆ GetUnsafe()

utils::SharedReadablePtr< dynamic_config::DocsMap > components::CachingComponentBase< dynamic_config::DocsMap >::GetUnsafe ( ) const

inherited

Returns: cache contents. May be nullptr regardless of MayReturnNull().

Definition at line 171 of file caching_component_base.hpp.

◆ InvalidateAsync()

void cache::CacheUpdateTrait::InvalidateAsync ( UpdateType update_type )

inherited

Non-blocking forced cache update of specified type.

See also: PeriodicTask::ForceStepAsync for behavior details

◆ MayReturnNull()

bool components::CachingComponentBase< dynamic_config::DocsMap >::MayReturnNull ( ) const

protectedvirtualinherited

Whether Get is expected to return nullptr.

Definition at line 202 of file caching_component_base.hpp.

◆ Name()

const std::string & cache::CacheUpdateTrait::Name ( ) const

inherited

Returns: name of the component

◆ OnAllComponentsAreStopping()

void components::ComponentBase::OnAllComponentsAreStopping ( )

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 58 of file component_base.hpp.

◆ OnCacheModified()

void cache::CacheUpdateTrait::OnCacheModified ( )

protectedinherited

Called in CachingComponentBase::Set during update to indicate that the cached data has been modified

◆ OnLoadingCancelled()

void components::ComponentBase::OnLoadingCancelled ( )

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 42 of file component_base.hpp.

◆ PreAssignCheck()

void components::CachingComponentBase< dynamic_config::DocsMap >::PreAssignCheck	(	const dynamic_config::DocsMap *	old_value_ptr,
		const dynamic_config::DocsMap *	new_value_ptr ) const

protectedvirtualinherited

If the option has-pre-assign-check is set true in static config, this function is called before assigning the new value to the cache.

Note: old_value_ptr and new_value_ptr can be nullptr.

Definition at line 214 of file caching_component_base.hpp.

◆ ReadContents()

std::unique_ptr< const dynamic_config::DocsMap > components::CachingComponentBase< dynamic_config::DocsMap >::ReadContents ( dump::Reader & reader ) const

protectedvirtualinherited

Definition at line 208 of file caching_component_base.hpp.

◆ Set() [1/2]

void components::CachingComponentBase< dynamic_config::DocsMap >::Set ( dynamic_config::DocsMap && value )

protectedinherited

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Definition at line 192 of file caching_component_base.hpp.

◆ Set() [2/2]

void components::CachingComponentBase< dynamic_config::DocsMap >::Set ( std::unique_ptr< const dynamic_config::DocsMap > value_ptr )

protectedinherited

Sets the new value of cache. As a result the Get() member function starts returning the value passed into this function after the Update() finishes.

Warning: Do not forget to update cache::UpdateStatisticsScope, otherwise the behavior is undefined.

Definition at line 189 of file caching_component_base.hpp.

◆ StopPeriodicUpdates()

void cache::CacheUpdateTrait::StopPeriodicUpdates ( )

protectedinherited

Stops periodic updates.

Warning: Should be called in destructor of derived class.

◆ UpdateAndListen()

concurrent::AsyncEventSubscriberScope components::CachingComponentBase< dynamic_config::DocsMap >::UpdateAndListen	(	Class *	obj,
		std::string	name,
		void(Class::*)(const std::shared_ptr< const dynamic_config::DocsMap > &)	func )

inherited

Subscribes to cache updates using a member function. Also immediately invokes the function with the current cache contents.

Definition at line 177 of file caching_component_base.hpp.

◆ UpdateSyncDebug()

void cache::CacheUpdateTrait::UpdateSyncDebug ( UpdateType update_type )

inherited

Forces a cache update of specified type.

Exceptions

If	`Update` throws

◆ WriteContents()

void components::CachingComponentBase< dynamic_config::DocsMap >::WriteContents	(	dump::Writer &	writer,
		const dynamic_config::DocsMap &	contents ) const

protectedvirtualinherited

Override to use custom serialization for cache dumps

Definition at line 206 of file caching_component_base.hpp.

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

userver/dynamic_config/updater/component.hpp

Detailed Description

Optional update event deduplication

Static options:

Static configuration example:

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Types

Protected Member Functions

Member Typedef Documentation

◆ DataType

◆ LoggableComponentBase

Member Enumeration Documentation

◆ Flag

Member Function Documentation

◆ Clear()

◆ Emplace()

◆ Get()

◆ GetComponentHealth()

◆ GetEventChannel()

◆ GetUnsafe()

◆ InvalidateAsync()

◆ MayReturnNull()

◆ Name()

◆ OnAllComponentsAreStopping()

◆ OnCacheModified()

◆ OnLoadingCancelled()

◆ PreAssignCheck()

◆ ReadContents()

◆ Set() [1/2]

◆ Set() [2/2]

◆ StopPeriodicUpdates()

◆ UpdateAndListen()

◆ UpdateSyncDebug()

◆ WriteContents()