Detailed Description

Contains functions and types to start a userver based service/tool.

Classes
class	AuthCheckerSettings
	Component that loads auth configuration settings from a components::Secdist component if the latter was registered in components::ComponentList. More...

class	CachingComponentBase
	Base class for caching components. More...

class	ClickHouse
	ClickHouse client component. More...

class	ComponentBase
	Base class for all application components, it depends on components::Logger and components::Tracer. More...

class	ComponentConfig

class	ComponentContext
	Class to retrieve other components. More...

class	ComponentList
	A list to keep a unique list of components to start with components::Run(), utils::DaemonMain() or components::RunOnce(). More...

class	ComponentsLoadCancelledException
	Exception that is thrown from components::ComponentContext::FindComponent() if a component load failed. More...

class	DefaultSecdistProvider
	Component that stores security related data (keys, passwords, ...). More...

class	DumpConfigurator
	Helper component that manages common configuration for userver dumps. More...

class	DynamicConfig
	Component that stores the dynamic config. More...

class	DynamicConfigClient
	Component that starts a clients::dynamic_config::Client client. More...

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

class	DynamicConfigUpdatesSinkBase
	Base class for components acting as dynamic config updates sinks. More...

class	FsCache
	Component for storing files in memory. More...

class	HttpClient
	Component that manages clients::http::Client. More...

struct	InMemoryConfig

class	Logging
	Logging component More...

class	LoggingConfigurator
	Helper component to configure logging. More...

class	ManagerControllerComponent
	Component that prepares the engine internals and starts all the other components. More...

class	Mongo
	MongoDB client component. More...

class	MongoCache
	Base class for all caches polling mongo collection More...

class	MultiMongo
	Dynamically configurable MongoDB client component. More...

class	PostgreCache
	Caching component for PostgreSQL. See Caching Component for PostgreSQL. More...

class	Postgres
	PosgreSQL client component. More...

class	ProcessStarter
	Component for getting the engine::subprocess::ProcessStarter. More...

class	RabbitMQ
	RabbitMQ (AMQP 0.9.1) client component. More...

class	RawComponentBase
	The base class for all components. Don't use it for application components, use ComponentBase instead. More...

class	Redis
	Valkey and Redis client component. More...

class	Secdist
	Component that stores security related data (keys, passwords, ...). More...

class	Server
	Component that listens for incoming requests, manages incoming connections and passes the requests to the appropriate handler. More...

class	SingleThreadedTaskProcessors
	Component that starts multiple single threaded task processors. More...

class	State

class	StatisticsStorage
	Component that keeps a utils::statistics::Storage storage for metrics. More...

class	SystemStatisticsCollector
	Component for system resource usage statistics collection. More...

class	TcpAcceptorBase
	Component for accepting incoming TCP connections. More...

class	TestsuiteSupport
	Testsuite support component. More...

class	Tracer
	Component that initializes the request tracing facilities. More...

Typedefs
using	LoggableComponentBase = ComponentBase

using	ComponentConfigMap = std::unordered_map<std::string, const ComponentConfig&>

Enumerations
enum class	ComponentHealth { kOk , kFallback , kFatal }
	State of the component. More...

enum class	ConfigFileMode { kRequired , kNotRequired }

enum class	ValidationMode { kOnlyTurnedOn , kAll }

enum class	ServiceLifetimeStage { kLoading , kOnAllComponentsLoadedIsRunning , kRunning , kGracefulShutdown , kOnAllComponentsAreStoppingIsRunning , kStopping }
	All components pass through these stages during the service lifetime. More...

Functions
std::string_view	GetCurrentComponentName (const ComponentContext &context)
	Equivalent to components::ComponentContext::GetComponentName, but works with forward declaration of the components::ComponentContext.

ValidationMode	Parse (const yaml_config::YamlConfig &value, formats::parse::To< ValidationMode >)

ComponentConfig	Parse (const yaml_config::YamlConfig &value, formats::parse::To< ComponentConfig >)

ComponentList	MinimalServerComponentList ()
	Returns a list of components to start a basic HTTP server.

void	Run (const std::string &config_path, const std::optional< std::string > &config_vars_path, const std::optional< std::string > &config_vars_override_path, const ComponentList &component_list)

void	Run (const InMemoryConfig &config, const ComponentList &component_list)

void	RunOnce (const std::string &config_path, const std::optional< std::string > &config_vars_path, const std::optional< std::string > &config_vars_override_path, const ComponentList &component_list)

void	RunOnce (const InMemoryConfig &config, const ComponentList &component_list)

void	RequestStop ()

ComponentList	CommonComponentList ()
	Returns the most common list of components with runtime config updates and HTTP client.

ComponentList	CommonServerComponentList ()
	Returns the most common list of components to start a fully functional server.

ComponentList	MinimalComponentList ()
	Returns a list of components to do basic logging, component initialization and configuration.

std::string_view	ToString (ServiceLifetimeStage)
	Converts a components::ServiceLifetimeStage to debug string for logging.

Variables
template<typename Component>
constexpr bool	kHasValidate = false

template<typename Component>
constexpr bool	kForceNoValidation = false

template<typename Component>
constexpr auto	kConfigFileMode = ConfigFileMode::kRequired

template<>
constexpr bool	kHasValidate< HttpClient > = true

template<>
constexpr bool	kHasValidate< Postgres > = true

template<>
constexpr bool	kHasValidate< TestsuiteSupport > = true

template<>
constexpr bool	kHasValidate< Secdist > = true

template<>
constexpr auto	kConfigFileMode< Secdist > = ConfigFileMode::kNotRequired

template<>
constexpr bool	kHasValidate< DefaultSecdistProvider > = true

template<>
constexpr bool	kHasValidate< DumpConfigurator > = true

template<>
constexpr bool	kHasValidate< FsCache > = true

template<>
constexpr bool	kHasValidate< LoggingConfigurator > = true
	}@

template<>
constexpr auto	kConfigFileMode< ManagerControllerComponent > = ConfigFileMode::kNotRequired

template<>
constexpr bool	kHasValidate< ProcessStarter > = true

template<>
constexpr bool	kHasValidate< SingleThreadedTaskProcessors > = true

template<>
constexpr bool	kHasValidate< StatisticsStorage > = true

template<>
constexpr auto	kConfigFileMode< StatisticsStorage > = ConfigFileMode::kNotRequired

template<>
constexpr bool	kHasValidate< DynamicConfigClient > = true

template<>
constexpr bool	kHasValidate< DynamicConfig > = true

template<>
constexpr auto	kConfigFileMode< DynamicConfig > = ConfigFileMode::kNotRequired

template<>
constexpr bool	kHasValidate< DynamicConfigClientUpdater > = true

template<>
constexpr bool	kHasValidate< Logging > = true

template<>
constexpr bool	kHasValidate< Server > = true

template<>
constexpr bool	kHasValidate< AuthCheckerSettings > = true

template<>
constexpr auto	kConfigFileMode< AuthCheckerSettings > = ConfigFileMode::kNotRequired

template<>
constexpr bool	kHasValidate< Tracer > = true

template<>
constexpr auto	kConfigFileMode< Tracer > = ConfigFileMode::kNotRequired

template<>
constexpr bool	kHasValidate< SystemStatisticsCollector > = true

const std::string	kFetchAndParseStage = "fetch_and_parse"

constexpr std::chrono::milliseconds	kCpuRelaxThreshold {10}

constexpr std::chrono::milliseconds	kCpuRelaxInterval {2}

template<class MongoCacheTraits>
constexpr bool	kHasValidate< MongoCache< MongoCacheTraits > > = true

template<>
constexpr bool	kHasValidate< Mongo > = true

template<>
constexpr bool	kHasValidate< MultiMongo > = true

template<typename PostgreCachePolicy>
constexpr bool	kHasValidate< PostgreCache< PostgreCachePolicy > > = true

template<>
constexpr bool	kHasValidate< Redis > = true

template<>
constexpr bool	kHasValidate< ClickHouse > = true

template<typename Client>
constexpr bool	kHasValidate< ugrpc::client::SimpleClientComponent< Client > > = true

template<>
constexpr bool	kHasValidate< RabbitMQ > = true

template<>
constexpr bool	kHasValidate< urabbitmq::ConsumerComponentBase > = true

Typedef Documentation

◆ ComponentConfigMap

using components::ComponentConfigMap = std::unordered_map<std::string, const ComponentConfig&>

Definition at line 29 of file component_config.hpp.

◆ LoggableComponentBase

using components::LoggableComponentBase = ComponentBase

Deprecated: use components::ComponentBase instead.

Definition at line 71 of file component_base.hpp.

Enumeration Type Documentation

◆ ComponentHealth

enum class components::ComponentHealth

strong

State of the component.

Enumerator
kOk	component is alive and fine
kFallback	component in fallback state, but the service keeps working
kFatal	component is sick, service can not work without it

Definition at line 17 of file raw_component_base.hpp.

◆ ConfigFileMode

enum class components::ConfigFileMode

strong

Whether the static config for the component must always be present, or can be missing

Enumerator
kRequired	component must be setup in config
kNotRequired	component must be not setup in config

Definition at line 28 of file raw_component_base.hpp.

◆ ServiceLifetimeStage

enum class components::ServiceLifetimeStage

strong

All components pass through these stages during the service lifetime.

See also: Component system

Enumerator
kLoading	Constructors are running for all registered components. Components can depend on each other at this stage by calling components::ComponentContext::FindComponent and friends. If any component throws an exception, then the service transitions into ServiceLifetimeStage::kOnAllComponentsAreStoppingIsRunning stage.
kOnAllComponentsLoadedIsRunning	components::ComponentBase::OnAllComponentsLoaded (noop by default) is running for all components. This stage starts after constructors for all components have completed without an exception. The order of `OnAllComponentsLoaded` hooks invocations respects the order of components defined at ServiceLifetimeStage::kComponentsLoading stage.
kRunning	This stage marks that all `OnAllComponentsLoaded` hooks (as described in ServiceLifetimeStage::kOnAllComponentsLoadedIsRunning) have completed successfully (without an exception). At this point the service is fully running. This stage ends once the service receives a shutdown signal (`SIGINT` or `SIGTERM`).
kGracefulShutdown	The service waits for `graceful_shutdown_interval` (0 by default) before continuing with the actual service shutdown in ServiceLifetimeStage::kOnAllComponentsAreStoppingIsRunning. See also components::ManagerControllerComponent Example: components_manager: graceful_shutdown_interval: 10s
kOnAllComponentsAreStoppingIsRunning	components::ComponentBase::OnAllComponentsAreStopping (noop by default) is running for all components. This stage starts once the service has received a shutdown signal (see ServiceLifetimeStage::kRunning) and ServiceLifetimeStage::kGracefulShutdown stage (if any) has completed. If an error occurs during service startup, then `OnAllComponentsAreStopping` runs after components::ComponentBase::OnLoadingCancelled for all constructed components. The order of `OnAllComponentsAreStopping` hooks invocations respects the order of components defined at ServiceLifetimeStage::kComponentsLoading stage (they run in the reverse-dependency order).
kStopping	Destructors are running for all components. This stage starts once ServiceLifetimeStage::kOnAllComponentsAreStoppingIsRunning stage. If an error occurs during service startup, then destructors run after ServiceLifetimeStage::kOnAllComponentsAreStoppingIsRunning for all constructed components. The order of destructor invocations respects the order of components defined at ServiceLifetimeStage::kComponentsLoading stage (they run in the reverse-dependency order).

Definition at line 44 of file state.hpp.

◆ ValidationMode

enum class components::ValidationMode

strong

Definition at line 12 of file static_config_validator.hpp.

Function Documentation

◆ RequestStop()

void components::RequestStop ( )

Requests stop of the component system. The service will be eventually stopped.

◆ Run() [1/2]

void components::Run	(	const InMemoryConfig &	config,
		const ComponentList &	component_list )

Starts a server with the provided component list and config. Reopens the logging files on SIGUSR1.

See also: utils::DaemonMain

◆ Run() [2/2]

void components::Run	(	const std::string &	config_path,
		const std::optional< std::string > &	config_vars_path,
		const std::optional< std::string > &	config_vars_override_path,
		const ComponentList &	component_list )

Starts a server with the provided component list and config loaded from file. Reopens the logging files on SIGUSR1.

See also: utils::DaemonMain

◆ RunOnce() [1/2]

void components::RunOnce	(	const InMemoryConfig &	config,
		const ComponentList &	component_list )

Runs the component list once with the config.

See also: utils::DaemonMain

◆ RunOnce() [2/2]

void components::RunOnce	(	const std::string &	config_path,
		const std::optional< std::string > &	config_vars_path,
		const std::optional< std::string > &	config_vars_override_path,
		const ComponentList &	component_list )