Component that does a periodic update of runtime configs. More...

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

Inheritance diagram for components::DynamicConfigClientUpdater:

Collaboration diagram for components::DynamicConfigClientUpdater:

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

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

void	Update (cache::UpdateType update_type, const std::chrono::system_clock::time_point &last_update, const std::chrono::system_clock::time_point &now, cache::UpdateStatisticsScope &) override
	Should be overridden in a derived class to align the stored data with some data source.

Public Member Functions inherited from components::CachingComponentBase< dynamic_config::DocsMap >
	CachingComponentBase (const ComponentConfig &config, const ComponentContext &)

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 ()

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::CachingComponentBase< dynamic_config::DocsMap >
static yaml_config::Schema	GetStaticConfigSchema ()

Static Public Member Functions inherited from components::LoggableComponentBase
static yaml_config::Schema	GetStaticConfigSchema ()

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

Additional Inherited Members
Public Types inherited from components::CachingComponentBase< dynamic_config::DocsMap >
using	DataType = dynamic_config::DocsMap

Protected Types inherited from cache::CacheUpdateTrait
enum class	Flag { kNone = 0 , kNoFirstUpdate = 1 << 0 }
	Periodic update flags. More...

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

void	Set (dynamic_config::DocsMap &&value)

void	Emplace (Args &&... args)

void	Clear ()

virtual bool	MayReturnNull () const

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

Protected Member Functions inherited from cache::CacheUpdateTrait
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	OnCacheModified ()

	CacheUpdateTrait (CacheUpdateTrait &&)=delete

CacheUpdateTrait &	operator= (CacheUpdateTrait &&)=delete

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

Detailed Description

Component that does a periodic update of runtime configs.

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	-
load-only-my-values	request from the client only the values used by this service	-
fallback-path	a path to the fallback config to load the required config names from it	-
fs-task-processor	name of the task processor to run the blocking file write operations	-
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
      fallback-path: $runtime_config_path
      fallback-path#fallback: /some/path/to/runtime_config.json
      fs-task-processor: fs-task-processor
 
      # options from components::CachingComponentBase
      update-types: full-and-incremental
      update-interval: 5s
      update-jitter: 2s
      full-update-interval: 5m
      first-update-fail-ok: false
      config-settings: true
      additional-cleanup-interval: 5m
      testsuite-force-periodic-update: true

Definition at line 73 of file component.hpp.

Member Function Documentation

◆ Update()

void components::DynamicConfigClientUpdater::Update	(	cache::UpdateType	type,
		const std::chrono::system_clock::time_point &	last_update,
		const std::chrono::system_clock::time_point &	now,
		cache::UpdateStatisticsScope &	stats_scope
	)

overridevirtual

Should be overridden in a derived class to align the stored data with some data source.

Update implementation should do one of the following:

A. If the update succeeded and has changes...

call CachingComponentBase::Set to update the stored value and send a notification to subscribers
call UpdateStatisticsScope::Finish
return normally (an exception is allowed in edge cases) B. If the update succeeded and verified that there are no changes...

DON'T call CachingComponentBase::Set
call UpdateStatisticsScope::FinishNoChanges
return normally (an exception is allowed in edge cases) C. If the update failed...

DON'T call CachingComponentBase::Set
call UpdateStatisticsScope::FinishWithError, or...
throw an exception, which will be logged nicely

Parameters

type	type of the update
last_update	time of the last update (value of `now` from previous invocation of Update or default constructed value if this is the first Update).
now	current time point

Exceptions

std::exception on update failure

See also: Basics of Caches

Implements cache::CacheUpdateTrait.

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

userver/dynamic_config/updater/component.hpp

Public Member Functions

Static Public Member Functions