#include <userver/cache/base_postgres_cache.hpp>

Detailed Description

template<typename PostgreCachePolicy>
class components::PostgreCache< PostgreCachePolicy >

Caching component for PostgreSQL. See Caching Component for PostgreSQL.

See also: Caching Component for PostgreSQL, Basics of Caches

Examples: samples/postgres_auth/user_info_cache.hpp.

Definition at line 348 of file base_postgres_cache.hpp.

Inheritance diagram for components::PostgreCache< PostgreCachePolicy >:

Public Types
using	PolicyType = PostgreCachePolicy
using	ValueType = pg_cache::detail::ValueType<PolicyType>
using	RawValueType = pg_cache::detail::RawValueType<PolicyType>
using	DataType = pg_cache::detail::DataCacheContainerType<PolicyType>
using	PolicyCheckerType = pg_cache::detail::PolicyChecker<PostgreCachePolicy>
using	UpdatedFieldType = pg_cache::detail::UpdatedFieldType<PostgreCachePolicy>
using	BaseType = typename PolicyCheckerType::BaseType

Public Member Functions
	PostgreCache (const ComponentConfig &, const ComponentContext &)
utils::SharedReadablePtr< DataCacheContainerType< PostgreCachePolicy > >	Get () const final
utils::SharedReadablePtr< DataCacheContainerType< PostgreCachePolicy > >	GetUnsafe () const
concurrent::AsyncEventSubscriberScope	UpdateAndListen (Class obj, std::string name, void(Class::func)(const std::shared_ptr< const DataCacheContainerType< PostgreCachePolicy > > &))
concurrent::AsyncEventChannel< const std::shared_ptr< const DataCacheContainerType< PostgreCachePolicy > > & > &	GetEventChannel ()
const std::string &	Name () const noexcept
void	InvalidateAsync (UpdateType update_type)
	Non-blocking forced cache update of specified type.
void	InvalidateAsync (UpdateType update_type)
	Non-blocking forced cache update of specified type.
ComponentHealth	GetComponentHealth () const override
void	OnLoadingCancelled () override
void	OnAllComponentsLoaded () override
void	OnGracefulShutdown (engine::Deadline serving_shutdown_deadline) override
void	OnAllComponentsAreStopping () override
void	UpdateSyncDebug (UpdateType update_type)
	Forces a synchronous cache update of specified type.

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

Static Public Attributes
static constexpr bool	kIncrementalUpdates = pg_cache::detail::WantIncrementalUpdates<PolicyType>
static constexpr auto	kClusterHostTypeFlags = pg_cache::detail::ClusterHostType<PolicyType>()
static constexpr auto	kName = PolicyType::kName

Protected Types
using	LoggableComponentBase
enum	Flag
	Periodic update flags. More...

Protected Member Functions
void	Set (std::unique_ptr< const DataCacheContainerType< PostgreCachePolicy > > value_ptr)
	Sets the new value of cache. As a result, Get member function starts returning the new value.
void	Set (DataCacheContainerType< PostgreCachePolicy > &&value)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
void	Attach (const std::shared_ptr< const DataCacheContainerType< PostgreCachePolicy > > &value_ptr)
void	Emplace (Args &&... args)
void	Clear ()
	Clears the content of the cache by string a default constructed T.
virtual void	PreAssignCheck (const DataCacheContainerType< PostgreCachePolicy > old_value_ptr, const DataCacheContainerType< PostgreCachePolicy > 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	UpdateSyncDebug (UpdateType update_type)
	Forces a synchronous cache update of specified type.
AllowedUpdateTypes	GetAllowedUpdateTypes () const
	Update types configured for the cache.
void	OnCacheModified () noexcept
virtual utils::Flags< Flag >	GetStartFlags () const
	Returns flags for cache start.
void	EarlyStartPeriodicUpdates (utils::Flags< Flag > flags)
	Call this to start periodic updates just now, not after the constructor.
void	EarlyStartPeriodicUpdates (utils::Flags< Flag > flags)
	Call this to start periodic updates just now, not after the constructor.

virtual void	WriteContents (dump::Writer &writer, const DataCacheContainerType< PostgreCachePolicy > &contents) const
virtual std::unique_ptr< const DataCacheContainerType< PostgreCachePolicy > >	ReadContents (dump::Reader &reader) const

Member Typedef Documentation

◆ BaseType

template<typename PostgreCachePolicy>

using components::PostgreCache< PostgreCachePolicy >::BaseType = typename PolicyCheckerType::BaseType

Definition at line 357 of file base_postgres_cache.hpp.

◆ DataType

template<typename PostgreCachePolicy>

using components::PostgreCache< PostgreCachePolicy >::DataType = pg_cache::detail::DataCacheContainerType<PolicyType>

Definition at line 354 of file base_postgres_cache.hpp.

◆ LoggableComponentBase

using components::ComponentBase::LoggableComponentBase

protectedinherited

Deprecated: use components::ComponentBase instead.

Definition at line 79 of file component_base.hpp.

◆ PolicyCheckerType

template<typename PostgreCachePolicy>

using components::PostgreCache< PostgreCachePolicy >::PolicyCheckerType = pg_cache::detail::PolicyChecker<PostgreCachePolicy>

Definition at line 355 of file base_postgres_cache.hpp.

◆ PolicyType

template<typename PostgreCachePolicy>

using components::PostgreCache< PostgreCachePolicy >::PolicyType = PostgreCachePolicy

Definition at line 351 of file base_postgres_cache.hpp.

◆ RawValueType

template<typename PostgreCachePolicy>

using components::PostgreCache< PostgreCachePolicy >::RawValueType = pg_cache::detail::RawValueType<PolicyType>

Definition at line 353 of file base_postgres_cache.hpp.

◆ UpdatedFieldType

template<typename PostgreCachePolicy>

using components::PostgreCache< PostgreCachePolicy >::UpdatedFieldType = pg_cache::detail::UpdatedFieldType<PostgreCachePolicy>

Definition at line 356 of file base_postgres_cache.hpp.

◆ ValueType

template<typename PostgreCachePolicy>

using components::PostgreCache< PostgreCachePolicy >::ValueType = pg_cache::detail::ValueType<PolicyType>

Definition at line 352 of file base_postgres_cache.hpp.

Member Enumeration Documentation

◆ Flag

enum cache::CacheUpdateTrait::Flag

strongprotectedinherited

Periodic update flags.

Definition at line 89 of file cache_update_trait.hpp.

Constructor & Destructor Documentation

◆ PostgreCache()

template<typename PostgreCachePolicy>

components::PostgreCache< PostgreCachePolicy >::PostgreCache	(	const ComponentConfig &	config,
		const ComponentContext &	context )

Definition at line 413 of file base_postgres_cache.hpp.

Member Function Documentation

◆ Attach()

void components::CachingComponentBase< DataCacheContainerType< PostgreCachePolicy > >::Attach ( const std::shared_ptr< const DataCacheContainerType< PostgreCachePolicy > > & value_ptr )

protectedinherited

Attach the value of cache. As a result the Get() member function starts returning the value passed into this function after the Update() finishes. Does not take over into sole ownership. Do not use unless absolutely necessary. The object must be strictly thread-safe.

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

◆ Get()

utils::SharedReadablePtr< DataCacheContainerType< PostgreCachePolicy > > components::CachingComponentBase< DataCacheContainerType< PostgreCachePolicy > >::Get ( ) const

finalvirtualinherited

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).

Implements cache::DataProvider< T >.

◆ GetComponentHealth()

ComponentHealth components::ComponentBase::GetComponentHealth ( ) const

inlineoverrideinherited

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

Warning: The function is called concurrently from multiple threads.

Definition at line 35 of file component_base.hpp.

◆ GetStaticConfigSchema()

template<typename PostgreCachePolicy>

yaml_config::Schema components::PostgreCache< PostgreCachePolicy >::GetStaticConfigSchema ( )

static

Definition at line 695 of file base_postgres_cache.hpp.

◆ GetUnsafe()

utils::SharedReadablePtr< DataCacheContainerType< PostgreCachePolicy > > components::CachingComponentBase< DataCacheContainerType< PostgreCachePolicy > >::GetUnsafe ( ) const

inherited

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

◆ InvalidateAsync() [1/2]

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

inherited

Non-blocking forced cache update of specified type.

See also: PeriodicTask::ForceStepAsync for behavior details

◆ InvalidateAsync() [2/2]

( UpdateType update_type )

inherited

Non-blocking forced cache update of specified type.

See also: PeriodicTask::ForceStepAsync for behavior details

◆ Name()

( ) const

inherited

Returns: name of the component

◆ OnAllComponentsAreStopping()

void components::ComponentBase::OnAllComponentsAreStopping ( )

inlineoverrideinherited

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.

Definition at line 70 of file component_base.hpp.

◆ OnAllComponentsLoaded()

void components::ComponentBase::OnAllComponentsLoaded ( )

inlineoverrideinherited

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.

Definition at line 51 of file component_base.hpp.

◆ OnCacheModified()

void cache::CacheUpdateTrait::OnCacheModified ( )

protectednoexceptinherited

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

◆ OnGracefulShutdown()

void components::ComponentBase::OnGracefulShutdown ( engine::Deadline serving_shutdown_deadline )

overrideinherited

Serving components like HTTP and gRPC servers may use this function to stop accepting new requests and shutdown serving in the given time interval. Application components likely do not need to override it.

Parameters

[in] serving_shutdown_deadline The deadline until already running requests should be allowed to complete. The component is supposed to stop accepting new requests and continue processing of already active requests until this deadline (unless those requests finish earlier). And it might completely shutdown requests processing when the deadline is reached (or when no active requests left).

◆ OnLoadingCancelled()

void components::ComponentBase::OnLoadingCancelled ( )

inlineoverrideinherited

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.

Definition at line 42 of file component_base.hpp.

◆ PreAssignCheck()

virtual void components::CachingComponentBase< DataCacheContainerType< PostgreCachePolicy > >::PreAssignCheck	(	const DataCacheContainerType< PostgreCachePolicy > *	old_value_ptr,
		const DataCacheContainerType< PostgreCachePolicy > *	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.

◆ Set()

void components::CachingComponentBase< DataCacheContainerType< PostgreCachePolicy > >::Set ( std::unique_ptr< const DataCacheContainerType< PostgreCachePolicy > > value_ptr )

protectedinherited

Sets the new value of cache. As a result, Get member function starts returning the new value.

Notifies subscribers after setting the new value, see UpdateAndListen. Should only be called from Update normally.

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

◆ UpdateAndListen()

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

inherited

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

◆ UpdateSyncDebug() [1/2]

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

inherited

Forces a synchronous cache update of specified type.

Warning: This method is intended for tests and debugging only. In production code use InvalidateAsync instead. The reasons are:

InvalidateAsync shifts the time of the next update as if a periodic update has just happened. UpdateSyncDebug does not do that: it locks the mutex and performs an additional update on the side, which puts extra load on the CPU and on the data source.
The cache we subscribe to sends events as part of its own update. If the callback does something lengthy, e.g. updating another cache, this affects the cache we subscribe to: it may disrupt its updates and cause a traffic jam in the whole chain of caches. InvalidateAsync is not subject to this. On top of that, UpdateSyncDebug will block the cache we subscribe to for the time we wait for the previous update of the dependent cache to finish (if one was in progress).
InvalidateAsync robustly handles situations with repeated update requests, see the docs of PeriodicTask::ForceStepAsync, on top of which it is implemented. UpdateSyncDebug tries to lock the mutex over and over and performs as many updates as were requested, even if they were requested many times in a row.
If UpdateSyncDebug is called before the periodic updates of the current cache have started (they start after the constructor of the derived cache finishes), the behavior is undefined, because the state of the periodic updates is not set up yet, while an update was already requested. InvalidateAsync handles this case: in that situation nothing happens.

See also: InvalidateAsync

Exceptions

If	Update throws

◆ UpdateSyncDebug() [2/2]

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

inherited

Forces a synchronous cache update of specified type.

Warning: This method is intended for tests and debugging only. In production code use InvalidateAsync instead. The reasons are:

InvalidateAsync shifts the time of the next update as if a periodic update has just happened. UpdateSyncDebug does not do that: it locks the mutex and performs an additional update on the side, which puts extra load on the CPU and on the data source.
The cache we subscribe to sends events as part of its own update. If the callback does something lengthy, e.g. updating another cache, this affects the cache we subscribe to: it may disrupt its updates and cause a traffic jam in the whole chain of caches. InvalidateAsync is not subject to this. On top of that, UpdateSyncDebug will block the cache we subscribe to for the time we wait for the previous update of the dependent cache to finish (if one was in progress).
InvalidateAsync robustly handles situations with repeated update requests, see the docs of PeriodicTask::ForceStepAsync, on top of which it is implemented. UpdateSyncDebug tries to lock the mutex over and over and performs as many updates as were requested, even if they were requested many times in a row.
If UpdateSyncDebug is called before the periodic updates of the current cache have started (they start after the constructor of the derived cache finishes), the behavior is undefined, because the state of the periodic updates is not set up yet, while an update was already requested. InvalidateAsync handles this case: in that situation nothing happens.

See also: InvalidateAsync

Exceptions

If	Update throws

◆ WriteContents()

virtual void components::CachingComponentBase< DataCacheContainerType< PostgreCachePolicy > >::WriteContents	(	dump::Writer &	writer,
		const DataCacheContainerType< PostgreCachePolicy > &	contents ) const

protectedvirtualinherited

Override to use custom serialization for cache dumps

Member Data Documentation

◆ kClusterHostTypeFlags

template<typename PostgreCachePolicy>

auto components::PostgreCache< PostgreCachePolicy >::kClusterHostTypeFlags = pg_cache::detail::ClusterHostType<PolicyType>()

staticconstexpr

Definition at line 361 of file base_postgres_cache.hpp.

◆ kIncrementalUpdates

template<typename PostgreCachePolicy>

bool components::PostgreCache< PostgreCachePolicy >::kIncrementalUpdates = pg_cache::detail::WantIncrementalUpdates<PolicyType>

staticconstexpr

Definition at line 360 of file base_postgres_cache.hpp.

◆ kName

template<typename PostgreCachePolicy>

auto components::PostgreCache< PostgreCachePolicy >::kName = PolicyType::kName

staticconstexpr

Definition at line 362 of file base_postgres_cache.hpp.

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

userver/cache/base_postgres_cache.hpp

Detailed Description

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Types

Protected Member Functions

Member Typedef Documentation

◆ BaseType

◆ DataType

◆ LoggableComponentBase

◆ PolicyCheckerType

◆ PolicyType

◆ RawValueType

◆ UpdatedFieldType

◆ ValueType

Member Enumeration Documentation

◆ Flag

Constructor & Destructor Documentation

◆ PostgreCache()

Member Function Documentation

◆ Attach()

◆ Get()

◆ GetComponentHealth()

◆ GetStaticConfigSchema()

◆ GetUnsafe()

◆ InvalidateAsync() [1/2]

◆ InvalidateAsync() [2/2]

◆ Name()

◆ OnAllComponentsAreStopping()

◆ OnAllComponentsLoaded()

◆ OnCacheModified()

◆ OnGracefulShutdown()

◆ OnLoadingCancelled()

◆ PreAssignCheck()

◆ Set()

◆ UpdateAndListen()

◆ UpdateSyncDebug() [1/2]

◆ UpdateSyncDebug() [2/2]

◆ WriteContents()

Member Data Documentation

◆ kClusterHostTypeFlags

◆ kIncrementalUpdates

◆ kName