Components

Detailed Description

Components that could be used with utils::DaemonMain like functions; see Component system for an intro.

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⇦ Http server middlewares | Synchronization Primitives ⇨

Nested Groups
	HTTP Handlers
	Handlers are components that could be used by components::Server to process the incoming requests.
	Component Default Names
	Default names of components that are used in static config files.
	Http server middlewares
	Base classes for implementing and configuring http server middlewares.
	gRPC server middlewares
	Base classes for implementing and configuring grpc server middlewares.
	gRPC client middlewares
	Base classes for implementing and configuring grpc client middlewares.

Classes
class	easy::DependenciesComponent< Dependencies >
	Factory component for the dependencies from easy library. More...
class	components::HttpClient
	Component that manages clients::http::Client. More...
class	clients::dns::Component
	Caching DNS resolver component. More...
class	server::handlers::HttpHandlerBase
	Base class for all the Userver HTTP Handlers. More...
class	server::handlers::PingBase
	Base class for handlers that returns HTTP 200 if the service is OK and able to process requests. More...
class	server::handlers::Ping
	Ping handler implementation with warmup. More...
class	server::handlers::TestsControl
	Handler that allows to control the behavior of server from tests, and functional tests with testsuite in particular. More...
class	components::Postgres
	PosgreSQL client component. More...
class	components::TestsuiteSupport
	Testsuite support component. More...
class	grpc_protovalidate::client::ValidatorComponent
	Component for gRPC client response validation. More...
class	ugrpc::client::middlewares::log::Component
	Component for gRPC client logging. More...
class	grpc_protovalidate::server::ValidatorComponent
	Component for gRPC server request validation. More...
class	congestion_control::Component
	Component to limit too active requests, also known as CC. More...
class	server::handlers::HttpHandlerJsonBase
	Convenient base for handlers that accept requests with body in JSON format and respond with body in JSON format. More...
class	components::Secdist
	Component that stores security related data (keys, passwords, ...). More...
class	components::DefaultSecdistProvider
	Component that stores security related data (keys, passwords, ...). More...
class	ugrpc::server::ServiceComponentBase
	Base class for all the gRPC service components. More...
class	ugrpc::server::ServerComponent
	Component that configures and manages the gRPC server. More...
class	baggage::BaggageManagerComponent
	Component for relationship with header baggage. More...
class	components::CachingComponentBase< T >
	Base class for caching components. More...
class	cache::LruCacheComponent< Key, Value, Hash, Equal >
	Base class for LRU-cache components. More...
class	components::DumpConfigurator
	Helper component that manages common configuration for userver dumps. More...
class	components::FsCache
	Component for storing files in memory. More...
class	components::LoggingConfigurator
	Helper component to configure logging. More...
class	components::ManagerControllerComponent
	Component that prepares the engine internals and starts all the other components. More...
class	components::ProcessStarter
	Component for getting the engine::subprocess::ProcessStarter. More...
class	components::SingleThreadedTaskProcessors
	Component that starts multiple single threaded task processors. More...
class	components::StatisticsStorage
	Component that keeps a utils::statistics::Storage storage for metrics. More...
class	components::TcpAcceptorBase
	Component for accepting incoming TCP connections. More...
class	components::DynamicConfigClient
	Component that starts a clients::dynamic_config::Client client. More...
class	components::DynamicConfig
	Component that stores the dynamic config. More...
class	components::DynamicConfigClientUpdater
	Component that does a periodic update of runtime configs. More...
class	engine::TaskProcessorsLoadMonitor
	Component to monitor CPU usage for every TaskProcessor present in the service, and dump per-thread stats into metrics. More...
class	components::Logging
	Logging component More...
class	os_signals::ProcessorComponent
	A component for os_signals::Processor. More...
class	components::Server
	Component that listens for incoming requests, manages incoming connections and passes the requests to the appropriate handler. More...
class	components::AuthCheckerSettings
	Component that loads auth configuration settings from a components::Secdist component if the latter was registered in components::ComponentList. More...
class	server::handlers::DnsClientControl
	Handlers that controls the DNS client. More...
class	server::handlers::DynamicDebugLog
	Handler for forcing specific lines logging. Feature also known as dynamic debug logging. More...
class	server::handlers::HttpHandlerFlatbufBase< InputType, ReturnType >
	Convenient base for handlers that accept requests with body in Flatbuffer format and respond with body in Flatbuffer format. More...
class	server::handlers::HttpHandlerStatic
	Handler that returns HTTP 200 if file exist and returns file data with mapped content/type. More...
class	server::handlers::ImplicitOptions
	A "magical" handler that will respond to OPTIONS HTTP method for any other handler that cannot handle OPTIONS itself. More...
class	server::handlers::InspectRequests
	Handler that returns information about all in-flight requests. More...
class	server::handlers::Jemalloc
	Handler that controls the jemalloc allocator. More...
class	server::handlers::LogLevel
	Handler that controls logging levels of all the loggers. More...
class	server::handlers::OnLogRotate
	Handler that controls logging levels of all the loggers. More...
class	server::handlers::Restart
	Handler that stops the service. It is expected that an external system (e.g. systemd or supervisord) restarts the service afterwards. More...
class	server::handlers::ServerMonitor
	Handler that returns statistics data. More...
class	server::websocket::WebsocketHandlerBase
	Base class for WebSocket handler. More...
class	components::Tracer
	Component that initializes the request tracing facilities. More...
class	tracing::DefaultTracingManagerLocator
	Component that provides access to the actual TracingManager that is used in handlers and clients. More...
class	components::SystemStatisticsCollector
	Component for system resource usage statistics collection. More...
class	components::MongoCache< MongoCacheTraits >
	Base class for all caches polling mongo collection More...
class	components::Mongo
	MongoDB client component. More...
class	components::MultiMongo
	Dynamically configurable MongoDB client component. More...
class	storages::mongo::DistLockComponentBase
	Base class for mongo-based distlock worker components. More...
class	components::PostgreCache< PostgreCachePolicy >
	Caching component for PostgreSQL. See Caching Component for PostgreSQL. More...
class	storages::postgres::DistLockComponentBase
	Base class for postgres-based distlock worker components. More...
class	components::Redis
	Valkey and Redis client component. More...
class	components::ClickHouse
	ClickHouse client component. More...
class	ugrpc::client::ClientFactoryComponent
	Provides a ClientFactory in the component system. More...
class	ugrpc::client::CommonComponent
	Contains common machinery that's required for all ugrpc clients. More...
class	ugrpc::client::middlewares::headers_propagator::Component
	gRPC client middleware for sending headers stored by the respective HTTP and gRPC server middlewares. More...
class	ugrpc::client::MiddlewarePipelineComponent
	Component to create middlewares pipeline. More...
class	ugrpc::client::middlewares::testsuite::Component
	Component for gRPC client testsuite support. More...
class	ugrpc::client::SimpleClientComponent< Client >
	Template class for a simple gRPC client. More...
class	ugrpc::server::middlewares::access_log::Component
	gRPC server access log middleware component. Writes one TSKV log line per handled RPC in a static format. This log is intended to be collected, parsed and stored for audit or extended statistics purposes. More...
class	ugrpc::server::middlewares::congestion_control::Component
	Component for gRPC server logging. More...
class	ugrpc::server::middlewares::headers_propagator::Component
	Component for gRPC server headers_propagator. More...
class	ugrpc::server::middlewares::log::Component
	Component for gRPC server logging. More...
class	ugrpc::server::MiddlewarePipelineComponent
	Component to create middlewares pipeline. More...
class	kafka::ConsumerComponent
	Apache Kafka Consumer client component. More...
class	kafka::ProducerComponent
	Apache Kafka Producer client component. More...
class	components::RabbitMQ
	RabbitMQ (AMQP 0.9.1) client component. More...
class	storages::mysql::Component
	MySQL/MariaDB client component. More...
class	components::SQLite
	SQLite client component. More...
class	ydb::YdbComponent
	YDB client component. More...
class	ydb::CredentialsProviderComponent
	Credentials provider component for creating custom credentials provider factory. More...
class	ydb::DistLockComponentBase
	Base class for YDB-based distlock worker components. More...
class	otlp::LoggerComponent
	Component to configure logging via OTLP collector. More...

Typedefs
template<typename Middleware>
using	ugrpc::client::SimpleMiddlewareFactoryComponent
	The alias for a short-cut client factory.
template<typename Middleware>
using	ugrpc::server::SimpleMiddlewareFactoryComponent
	The alias for a short-cut server middleware factory.
using	ugrpc::client::middlewares::baggage::Component = SimpleMiddlewareFactoryComponent<Middleware>
	Component for gRPC client baggage.
using	ugrpc::client::middlewares::deadline_propagation::Component = SimpleMiddlewareFactoryComponent<Middleware>
	Component for gRPC client deadline_propagation. Update deadline from TaskInheritedData if it exists and more strict than context deadline.

Functions
ComponentList	components::MinimalServerComponentList ()
	Returns a list of components to start a basic HTTP server.
components::ComponentList	ugrpc::server::MinimalComponentList ()
	Returns a list of components to do a minimal grpc server configuration.
components::ComponentList	ugrpc::server::DefaultComponentList ()
	Returns a list of components to do a default grpc server configuration.
ComponentList	components::CommonComponentList ()
	Returns the most common list of components with runtime config updates and HTTP client.
ComponentList	components::CommonServerComponentList ()
	Returns the most common list of components to start a fully functional server.
ComponentList	components::MinimalComponentList ()
	Returns a list of components to do basic logging, component initialization and configuration.
components::ComponentList	ugrpc::client::MinimalComponentList ()
	Returns a list of components to do a minimal grpc client configuration.
components::ComponentList	ugrpc::client::DefaultComponentList ()
	Returns a list of components to do a default grpc client configuration.

Typedef Documentation

Component [1/2]

using ugrpc::client::middlewares::baggage::Component = SimpleMiddlewareFactoryComponent<Middleware>

Component for gRPC client baggage.

The component does not have any options for service config.

Static configuration example:

        grpc-client-baggage:
            # Nothing

See also

gRPC client middlewares

Definition at line 27 of file component.hpp.

Component [2/2]

using ugrpc::client::middlewares::deadline_propagation::Component = SimpleMiddlewareFactoryComponent<Middleware>

Component for gRPC client deadline_propagation. Update deadline from TaskInheritedData if it exists and more strict than context deadline.

See also

Deadline propagation

The component does not have any options for service config.

Static configuration example:

        grpc-client-deadline-propagation:
            # Nothing

See also

gRPC client middlewares

Definition at line 34 of file component.hpp.

SimpleMiddlewareFactoryComponent [1/2]

template<typename Middleware>

using ugrpc::client::SimpleMiddlewareFactoryComponent

Initial value:

 
    ::middlewares::impl::SimpleMiddlewareFactoryComponent<MiddlewareBase, Middleware, ClientInfo>

The alias for a short-cut client factory.

Static options:

Name	Description	Default value
enabled	the flag to enable/disable middleware in the pipeline	true

Example usage:

class AuthMiddleware final : public ugrpc::client::MiddlewareBase {
public:
    // Name of a middleware-factory that creates this middleware.
    static constexpr std::string_view kName = "grpc-auth-client";
 
    // 'Auth' is a group for authentication. See middlewares groups for more information.
    static inline const auto kDependency =
        middlewares::MiddlewareDependencyBuilder().InGroup<middlewares::groups::Auth>();
 
    AuthMiddleware();
 
    ~AuthMiddleware() override;
 
    void PreStartCall(ugrpc::client::MiddlewareCallContext& context) const override;
};
 
// This component creates Middleware. Name of the component is 'Middleware::kName'.
// In this case we use a short-cut for defining a middleware-factory, but you can create your own factory by
// inheritance from 'ugrpc::client::MiddlewareFactoryComponentBase'
using AuthComponent = ugrpc::client::SimpleMiddlewareFactoryComponent<AuthMiddleware>;
 

Static config example

        grpc-auth-client:
 
        grpc-client-middlewares-pipeline:
            middlewares:
                grpc-auth-client:
                    enabled: true  # register the middleware in the pipeline

Definition at line 157 of file base.hpp.

SimpleMiddlewareFactoryComponent [2/2]

template<typename Middleware>

using ugrpc::server::SimpleMiddlewareFactoryComponent

Initial value:

 
    ::middlewares::impl::SimpleMiddlewareFactoryComponent<MiddlewareBase, Middleware, ServiceInfo>

The alias for a short-cut server middleware factory.

Static options:

Name	Description	Default value
enabled	the flag to enable/disable middleware in the pipeline	true

Example usage:

class Middleware final : public ugrpc::server::MiddlewareBase {
public:
    // Name of a middleware-factory that creates this middleware.
    static constexpr std::string_view kName = "grpc-server-auth";
 
    // 'Auth' is a group for auth authentication. See middlewares groups for more information.
    static inline const auto kDependency =
        middlewares::MiddlewareDependencyBuilder().InGroup<middlewares::groups::Auth>();
 
    Middleware();
 
    void OnCallStart(ugrpc::server::MiddlewareCallContext& context) const override;
};
 
// This component creates Middleware. Name of the component is 'Middleware::kName'.
// In this case we use a short-cut for defining a middleware-factory, but you can create your own factory by
// inheritance from 'ugrpc::server::MiddlewareFactoryComponentBase'
using AuthComponent = ugrpc::server::SimpleMiddlewareFactoryComponent<Middleware>;

Static config example

        grpc-server-auth:
 
        grpc-server-middlewares-pipeline:
            middlewares:
                grpc-server-auth:  # register the middleware in the pipeline
                    enabled: true

Definition at line 174 of file base.hpp.

Function Documentation

CommonComponentList()

ComponentList components::CommonComponentList

(

)

Returns the most common list of components with runtime config updates and HTTP client.

The list contains:

• everything from components::MinimalComponentList
• components::LoggingConfigurator
• components::DumpConfigurator
• components::TestsuiteSupport
• components::SystemStatisticsCollector
• components::HttpClient (default and "http-client-statistics")
• clients::dns::Component
• components::DynamicConfigClient
• components::DynamicConfigClientUpdater
• engine::TaskProcessorsLoadMonitor

CommonServerComponentList()

ComponentList components::CommonServerComponentList

(

)

Returns the most common list of components to start a fully functional server.

The list contains:

• components::Server
• server::handlers::DnsClientControl
• server::handlers::DynamicDebugLog
• server::handlers::ImplicitOptions
• server::handlers::InspectRequests
• server::handlers::Jemalloc
• server::handlers::LogLevel
• server::handlers::OnLogRotate
• server::handlers::ServerMonitor
• server::handlers::TestsControl
• components::AuthCheckerSettings
• congestion_control::Component

DefaultComponentList() [1/2]

components::ComponentList ugrpc::client::DefaultComponentList

(

)

Returns a list of components to do a default grpc client configuration.

The list contains:

• ugrpc::client::CommonComponent
• ugrpc::client::MiddlewarePipelineComponent
• ugrpc::client::middlewares::baggage::Component
• ugrpc::client::middlewares::deadline_propagation::Component
• ugrpc::client::middlewares::log::Component
• ugrpc::client::middlewares::headers_propagator::Component

DefaultComponentList() [2/2]

components::ComponentList ugrpc::server::DefaultComponentList

(

)

Returns a list of components to do a default grpc server configuration.

The list contains:

• ugrpc::server::ServerComponent
• ugrpc::server::MiddlewarePipelineComponent
• ugrpc::server::middlewares::baggage::Component
• ugrpc::server::middlewares::congestion_control::Component
• ugrpc::server::middlewares::deadline_propagation::Component
• ugrpc::server::middlewares::headers_propagator::Component
• ugrpc::server::middlewares::log::Component

MinimalComponentList() [1/3]

ComponentList components::MinimalComponentList

(

)

Returns a list of components to do basic logging, component initialization and configuration.

The list contains:

• os_signals::ProcessorComponent
• components::Logging
• components::Tracer
• components::ManagerControllerComponent
• components::StatisticsStorage
• components::DynamicConfig
• tracing::DefaultTracingManagerLocator

Examples

samples/tcp_service/main.cpp.

MinimalComponentList() [2/3]

components::ComponentList ugrpc::client::MinimalComponentList

(

)

Returns a list of components to do a minimal grpc client configuration.

The list contains:

• ugrpc::client::CommonComponent
• ugrpc::client::MiddlewarePipelineComponent
• ugrpc::client::middlewares::deadline_propagation::Component
• ugrpc::client::middlewares::log::Component

MinimalComponentList() [3/3]

components::ComponentList ugrpc::server::MinimalComponentList

(

)

Returns a list of components to do a minimal grpc server configuration.

The list contains:

• ugrpc::server::ServerComponent
• ugrpc::server::MiddlewarePipelineComponent
• ugrpc::server::middlewares::congestion_control::Component
• ugrpc::server::middlewares::deadline_propagation::Component
• ugrpc::server::middlewares::log::Component

MinimalServerComponentList()

ComponentList components::MinimalServerComponentList

(

)

Returns a list of components to start a basic HTTP server.

The list contains:

• all of components::MinimalComponentList
• components::Server
• components::AuthCheckerSettings

Examples

grpc-generic-proxy/main.cpp, postgresql/functional_tests/basic_chaos/postgres_service.cpp, samples/config_service/main.cpp, samples/flatbuf_service/main.cpp, samples/grpc_middleware_service/main.cpp, samples/grpc_service/main.cpp, samples/hello_service/main.cpp, samples/http_caching/main.cpp, samples/kafka_service/main.cpp, samples/mongo_service/main.cpp, samples/multipart_service/main.cpp, samples/postgres_auth/postgres_service.cpp, samples/postgres_service/main.cpp, samples/redis_service/main.cpp, samples/s3api/main.cpp, samples/static_service/main.cpp, samples/tcp_full_duplex_service/main.cpp, and samples/websocket_service/main.cpp.