A microservice for a Xentara system. More...

#include <process/Microservice.hpp>

Inheritance diagram for xentara::process::Microservice:

Classes
class	FallbackConfigHandler
	A helper object used to handle config parameters unknown to the sub class. More...

Public Member Functions
virtual internal	~Microservice ()=0
	Virtual destructor.

auto	name () const -> std::string
	Gets the name of the microservice.

auto	primaryKey () const -> std::string
	Gets the primary key of the microservice.

auto	uuid () const -> utils::core::Uuid
	Gets the UUID of the microservice.

virtual auto	createSubservice (const MicroserviceClass &microserviceClass, plugin::SharedFactory< Microservice > &factory) -> std::shared_ptr< Microservice >
	Called by the framework to create a new subservice of this microservice.

virtual auto	resolveAttribute (std::string_view name) -> const model::Attribute *
	Called by the framework to resolve an attribute with a specific name.

virtual auto	resolveTask (std::string_view name) -> std::shared_ptr< process::Task >
	Called by the framework to resolve a task with a specific name.

virtual auto	resolveEvent (std::string_view name) -> std::shared_ptr< process::Event >
	Called by the framework to resolve an event with a specific name.

virtual auto	readHandle (const model::Attribute &attribute) const noexcept -> data::ReadHandle
	Called by the framework to get a read handle for a specific attribute.

virtual auto	writeHandle (const model::Attribute &attribute) noexcept -> data::WriteHandle
	Called by the framework to get a write handle for a specific attribute.

Public Member Functions inherited from xentara::utils::tools::DisableCopy
constexpr	DisableCopy () noexcept=default

	DisableCopy (const DisableCopy &)=delete

DisableCopy &	operator= (const DisableCopy &)=delete

Protected Types
using	ConfigIntializer = memory::Initializer< memory::Array >
	Type alias for an initializer for the configuration.

Protected Member Functions
virtual auto	loadConfig (const ConfigIntializer &initializer, utils::json::decoder::Object &jsonObject, config::Resolver &resolver, const FallbackConfigHandler &fallbackHandler) -> void=0
	Called by the framework to load the microservice's configuration from a JSON object.

virtual auto	realize () -> void
	Called by the framework once all references have been resolved.

virtual auto	postRealize () -> void
	Called by the framework after all subservices have been realized.

virtual auto	prepare () -> void
	Called by the framework to prepare the microservice for operation.

virtual auto	postPrepare () -> void
	Called by the framework after all subservices have been prepared.

virtual auto	preCleanup () -> void
	Called by the framework before the subservices are cleaned up.

virtual auto	cleanup () -> void
	Called by the framework to clean up the microservice after operation.

auto	configBlock () const noexcept -> const memory::ArrayBlock &
	Gets the memory block that the configuration is stored in.

Detailed Description

A microservice for a Xentara system.

A microservice is an object that provides some sort of functionality can can be hooked into process pipelines.

See also: Microservices; Microservices in the Xentara user manual

Member Typedef Documentation

◆ ConfigIntializer

using xentara::process::Microservice::ConfigIntializer = memory::Initializer<memory::Array>

protected

Type alias for an initializer for the configuration.

Constructor & Destructor Documentation

◆ ~Microservice()

xentara::process::Microservice::~Microservice ( )

pure virtualdefault

Virtual destructor.

Member Function Documentation

◆ cleanup()

virtual auto xentara::process::Microservice::cleanup ( ) -> void

protectedvirtual

Called by the framework to clean up the microservice after operation.

This method is called by the framework after Xentara has completely shut down.

This method is called after the cleanup() method of any subservices. You can override preCleanup() if you need to perform actions before the subservices are cleaned up.

Default Implementation: The default implementation does nothing.

◆ configBlock()

auto xentara::process::Microservice::configBlock ( ) const -> const memory::ArrayBlock &

protectednoexcept

Gets the memory block that the configuration is stored in.

◆ createSubservice()

virtual auto xentara::process::Microservice::createSubservice	(	const MicroserviceClass &	microserviceClass,
		plugin::SharedFactory< Microservice > &	factory
	)		-> std::shared_ptr< Microservice >

virtual

Called by the framework to create a new subservice of this microservice.

The implementation for this method must use the given factory to create a new microservice of the given microservice class:

return factory.makeShared<MySubservice>();

If your driver requires access to the subservice later, you must store an std::weak_ptr to it somewhere.

The framework will call loadConfig() on the newly created microservice.

Default Implementation: The default implementation returns nullptr, denoting that the microservice does not support subservices.

Parameters

microserviceClass	The class for the new microservice
factory	The factory that must be used to create the microservice

Returns: The newly created microservice, or nullptr if the microservice does not support subservices of the given class

Exceptions

std::runtime_error The function must throw this exception (or a suitable subclass) if an error occurs

See also: Creating Plugin Element Objects

◆ loadConfig()

virtual auto xentara::process::Microservice::loadConfig	(	const ConfigIntializer &	initializer,
		utils::json::decoder::Object &	jsonObject,
		config::Resolver &	resolver,
		const FallbackConfigHandler &	fallbackHandler
	)		-> void

protectedpure virtual

Called by the framework to load the microservice's configuration from a JSON object.

Parameters

initializer	An initializer object for the memory block that contains the configuration. Use this object to access the storage for any configuration attributes you added to the config() array in the microservice class.
jsonObject	The JSON object
resolver	An object that allows you to resolve cross references
fallbackHandler	An object that handles config parameters unknown to the sub class. You should call the function call operator of this object for any config parameters you do not recognize.

Exceptions

std::runtime_error The function must throw this exception (or a suitable subclass) if an error occurs

See also: Loading Element Configs

Examples: LoadingElementConfig.cpp

◆ name()

auto xentara::process::Microservice::name ( ) const -> std::string

Gets the name of the microservice.

Note: The name is only known once the configuration of the microservice has been loaded.

Returns: The name of the microservice, in UTF-8 encoding.

◆ postPrepare()

virtual auto xentara::process::Microservice::postPrepare ( ) -> void

protectedvirtual

Called by the framework after all subservices have been prepared.

This method is similar to the prepare() method, but it is called after the prepare() method of subservices.

Exceptions

std::runtime_error The function must throw this exception (or a suitable subclass) if an error occurs

Default Implementation: The default implementation does nothing.

◆ postRealize()

virtual auto xentara::process::Microservice::postRealize ( ) -> void

protectedvirtual

Called by the framework after all subservices have been realized.

This method is similar to the realize() method, but it is called after the realize() method of subservices.

Exceptions

std::runtime_error The function must throw this exception (or a suitable subclass) if an error occurs

Default Implementation: The default implementation does nothing.

◆ preCleanup()

virtual auto xentara::process::Microservice::preCleanup ( ) -> void

protectedvirtual

Called by the framework before the subservices are cleaned up.

This method is similar to the cleanup() method, but it is called before the cleanup() method of subservices.

Default Implementation: The default implementation does nothing.

◆ prepare()

virtual auto xentara::process::Microservice::prepare ( ) -> void

protectedvirtual

Called by the framework to prepare the microservice for operation.

This method is called by the framework after all objects have been realized, but before any processing is done. It allows you to prepare the object for operation. This is the place where read and write handles for attributes should be fetched, for example.

This method is called before the prepare() method of any subservices. You can override postPrepare() if you need to perform actions after all subservices have been prepared.

Exceptions

std::runtime_error The function must throw this exception (or a suitable subclass) if an error occurs

Default Implementation: The default implementation does nothing.

See also: Loading Element Configs

◆ primaryKey()

auto xentara::process::Microservice::primaryKey ( ) const -> std::string

Gets the primary key of the microservice.

Note: The primary key is only fully known once the entire configuration has been loaded.

Returns: The primary key of the microservice, in UTF-8 encoding.

◆ readHandle()

virtual auto xentara::process::Microservice::readHandle ( const model::Attribute & attribute ) const -> data::ReadHandle

virtualnoexcept

Called by the framework to get a read handle for a specific attribute.

The implementation for this method must return a read handle for the given attribute's value.

Default Implementation: The default implementation returns an error handle with error data::ReadHandle::Error::Unknown.

Parameters

attribute The desired attribute. This will never be one of the standard configuration attributes, as these are handled automatically by the framework.

Returns: A read handle for the attribute, or an error handle with an appropriate error code on error

See also: Publishing Attributes

Examples: PublishingConfigAttributes.cpp

◆ realize()

virtual auto xentara::process::Microservice::realize ( ) -> void

protectedvirtual

Called by the framework once all references have been resolved.

This method is called by the framework after the configuration has been completely loaded and all references have been resolved, but before the objects are prepared for processing. Use this function to perform initialization that requires access to the objects you submitted to the resolver in loadConfig().

This method is called before the realize() method of any subservices. You can override postRealize() if you need to perform actions after all subservices have been realized.

Exceptions

std::runtime_error The function must throw this exception (or a suitable subclass) if an error occurs

Default Implementation: The default implementation does nothing.

See also: Loading Element Configs

◆ resolveAttribute()

virtual auto xentara::process::Microservice::resolveAttribute ( std::string_view name ) -> const model::Attribute *

virtual

Called by the framework to resolve an attribute with a specific name.

The implementation for this method must return a reference to the attribute with the given name, if the microservice supports it.

Attributes are always resolved after Xentara model elements. This means that when this function is called, all references to Xentara model elements you submitted in loadConfig() have already been resolved.

Default Implementation: The default implementation returns nullptr, denoting that the microservice does not provide an attribute with the given name.

Parameters

name	The name of the desired attribute, in UTF-8 encoding. This will never be one of the standard configuration attributes, as these are resolved automatically by the framework.

Returns: A pointer to the attribute description, or nullptr if the microservice does not provide an attribute with the given name

Exceptions

std::runtime_error The function must throw this exception (or a suitable subclass) if an error occurs

See also: Publishing Attributes

Examples: PublishingConfigAttributes.cpp

◆ resolveEvent()

virtual auto xentara::process::Microservice::resolveEvent ( std::string_view name ) -> std::shared_ptr< process::Event >

virtual

Called by the framework to resolve an event with a specific name.

The implementation for this method must return a pointer to the event with the given name. You can either create the event on demand from within this function, or return a pointer to an existing event.

If the event you which to return is not a shared object itself, but a regular member of the microservice, you can derive your microservice class from xentara::plugin::EnableSharedFromThis and use the aliasing constructor (8) of std::shared_ptr together with sharedFromThis():

return std::shared_ptr(sharedFromThis(), &_myEvent);

std::shared_ptr

Events are always resolved after Xentara model elements. This means that when this function is called, all references to Xentara model elements you submitted in loadConfig() have already been resolved.

Default Implementation: The default implementation returns nullptr, denoting that the microservice does not provide an event with the given name.

Parameters

name	The name of the desired event, in UTF-8 encoding

Returns: A pointer to the event, or nullptr if the microservice does not provide an event with the given name

Exceptions

std::runtime_error The function must throw this exception (or a suitable subclass) if an error occurs

See also: Publishing Events

◆ resolveTask()

virtual auto xentara::process::Microservice::resolveTask ( std::string_view name ) -> std::shared_ptr< process::Task >

virtual

Called by the framework to resolve a task with a specific name.

The implementation for this method must return a pointer to the task with the given name. You can either create the task on demand from within this function, or return a pointer to an existing task.

If the task you which to return is not a shared object itself, but a regular member of the microservice, you can derive your microservice class from xentara::plugin::EnableSharedFromThis and use the aliasing constructor (8) of std::shared_ptr together with sharedFromThis():

return std::shared_ptr(sharedFromThis(), &_myTask);

Tasks are always resolved after Xentara model elements. This means that when this function is called, all references to Xentara model elements you submitted in loadConfig() have already been resolved.

Default Implementation: The default implementation returns nullptr, denoting that the microservice does not provide a task with the given name.

Parameters

name	The name of the desired task, in UTF-8 encoding

Returns: A pointer to the task, or nullptr if the microservice does not provide a task with the given name

Exceptions

std::runtime_error The function must throw this exception (or a suitable subclass) if an error occurs

See also: Publishing Tasks

◆ uuid()

auto xentara::process::Microservice::uuid ( ) const -> utils::core::Uuid

Gets the UUID of the microservice.

Note: The UUID is only known once the configuration of the microservice has been loaded.

◆ writeHandle()

virtual auto xentara::process::Microservice::writeHandle ( const model::Attribute & attribute ) -> data::WriteHandle

virtualnoexcept

Called by the framework to get a write handle for a specific attribute.

The implementation for this method must return a write handle for the given attribute's value.

Default Implementation: The default implementation returns an error handle with error data::WriteHandle::Error::Unknown.

Parameters

attribute The desired attribute. This will never be one of the standard configuration attributes, as these are handled automatically by the framework.

Returns: A write handle for the attribute, or an error handle with an appropriate error code on error

See also: Publishing Attributes

Classes

Public Member Functions

Protected Types

Protected Member Functions

Detailed Description

Member Typedef Documentation

◆ ConfigIntializer

Constructor & Destructor Documentation

◆ ~Microservice()

Member Function Documentation

◆ cleanup()

◆ configBlock()

◆ createSubservice()

◆ loadConfig()

◆ name()

◆ postPrepare()

◆ postRealize()

◆ preCleanup()

◆ prepare()

◆ primaryKey()

◆ readHandle()

◆ realize()

◆ resolveAttribute()

◆ resolveEvent()

◆ resolveTask()

◆ uuid()

◆ writeHandle()