userver: components::MongoCache< MongoCacheTraits > Class Template Reference
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components::MongoCache< MongoCacheTraits > Class Template Reference

#include <userver/cache/base_mongo_cache.hpp>

Detailed Description

template<class MongoCacheTraits>
class components::MongoCache< MongoCacheTraits >

Base class for all caches polling mongo collection

You have to provide a traits class in order to use this.

Avoiding memory leaks

See components::CachingComponentBase

Static options:

All options of CachingComponentBase and

Name Description Default value
update-correction adjusts incremental updates window to overlap with previous update 0

Traits example:

All fields below (except for function overrides) are mandatory.

struct MongoCacheTraitsExample {
// Component name for component
static constexpr std::string_view kName = "mongo-dynamic-config";
// Collection to read from
static constexpr auto kMongoCollectionsField =
&storages::mongo::Collections::config;
// Update field name to use for incremental update (optional).
// When missing, incremental update is disabled.
// Please use reference here to avoid global variables
// initialization order issues.
static constexpr const std::string& kMongoUpdateFieldName =
mongo::db::taxi::config::kUpdated;
// Cache element type
using ObjectType = CachedObject;
// Cache element field name that is used as an index in the cache map
static constexpr auto kKeyField = &CachedObject::name;
// Type of kKeyField
using KeyType = std::string;
// Type of cache map, e.g. unordered_map, map, bimap
using DataType = std::unordered_map<KeyType, ObjectType>;
// Whether the cache prefers to read from replica (if true, you might get stale data)
static constexpr bool kIsSecondaryPreferred = true;
// Optional function that overrides BSON to ObjectType conversion
static constexpr auto DeserializeObject = &CachedObject::FromBson;
// or
static ObjectType DeserializeObject(const formats::bson::Document& doc) {
return doc["value"].As<ObjectType>();
}
// (default implementation calls doc.As<ObjectType>())
// For using default implementation
static constexpr bool kUseDefaultDeserializeObject = true;
// Optional function that overrides data retrieval operation
static storages::mongo::operations::Find GetFindOperation(
const std::chrono::system_clock::time_point& last_update,
const std::chrono::system_clock::time_point& now,
const std::chrono::system_clock::duration& correction) {
mongo::operations::Find find_op({});
find_op.SetOption(mongo::options::Projection{"key", "value"});
return find_op;
}
// (default implementation queries kMongoUpdateFieldName: {$gt: last_update}
// for incremental updates, and {} for full updates)
// For using default implementation
static constexpr bool kUseDefaultFindOperation = true;
// Whether update part of the cache even if failed to parse some documents
static constexpr bool kAreInvalidDocumentsSkipped = false;
// Component to get the collections
using MongoCollectionsComponent = components::MongoCollections;
};

Definition at line 122 of file base_mongo_cache.hpp.

+ Inheritance diagram for components::MongoCache< MongoCacheTraits >:
+ Collaboration diagram for components::MongoCache< MongoCacheTraits >:

Public Member Functions

 MongoCache (const ComponentConfig &, const ComponentContext &)
 
- Public Member Functions inherited from components::CachingComponentBase< MongoCacheTraits::DataType >
 CachingComponentBase (const ComponentConfig &config, const ComponentContext &)
 
utils::SharedReadablePtr< MongoCacheTraits::DataType > Get () const
 
utils::SharedReadablePtr< MongoCacheTraits::DataType > GetUnsafe () const
 
concurrent::AsyncEventSubscriberScope UpdateAndListen (Class *obj, std::string name, void(Class::*func)(const std::shared_ptr< const MongoCacheTraits::DataType > &))
 
concurrent::AsyncEventChannel< const std::shared_ptr< const MongoCacheTraits::DataType > & > & 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< MongoCacheTraits::DataType >
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 = MongoCacheTraits::kName
 

Additional Inherited Members

- Public Types inherited from components::CachingComponentBase< MongoCacheTraits::DataType >
using DataType
 
- 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< MongoCacheTraits::DataType >
void Set (std::unique_ptr< const MongoCacheTraits::DataType > value_ptr)
 
void Set (MongoCacheTraits::DataType &&value)
 
void Emplace (Args &&... args)
 
void Clear ()
 
virtual bool MayReturnNull () const
 
virtual void WriteContents (dump::Writer &writer, const MongoCacheTraits::DataType &contents) const
 
virtual std::unique_ptr< const MongoCacheTraits::DataType > 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
 
CacheUpdateTraitoperator= (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
 

Constructor & Destructor Documentation

◆ MongoCache()

template<class MongoCacheTraits >
components::MongoCache< MongoCacheTraits >::MongoCache ( const ComponentConfig & config,
const ComponentContext & context )

Definition at line 164 of file base_mongo_cache.hpp.

◆ ~MongoCache()

template<class MongoCacheTraits >
components::MongoCache< MongoCacheTraits >::~MongoCache ( )

Definition at line 200 of file base_mongo_cache.hpp.

Member Function Documentation

◆ GetStaticConfigSchema()

template<class MongoCacheTraits >
yaml_config::Schema components::MongoCache< MongoCacheTraits >::GetStaticConfigSchema ( )
static

Definition at line 346 of file base_mongo_cache.hpp.

Member Data Documentation

◆ kName

template<class MongoCacheTraits >
constexpr std::string_view components::MongoCache< MongoCacheTraits >::kName = MongoCacheTraits::kName
staticconstexpr

Definition at line 128 of file base_mongo_cache.hpp.


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