etl::LoadBalancer Class Reference

This class is used to manage connections to transaction processing processes. More...

#include <LoadBalancer.hpp>

Inheritance diagram for etl::LoadBalancer:

Collaboration diagram for etl::LoadBalancer:

Public Types
using	RawLedgerObjectType = org::xrpl::rpc::v1::RawLedgerObject
using	GetLedgerResponseType = org::xrpl::rpc::v1::GetLedgerResponse
using	OptionalGetLedgerResponseType = std::optional<GetLedgerResponseType>

Public Member Functions
	LoadBalancer (util::config::ClioConfigDefinition const &config, boost::asio::io_context &ioc, std::shared_ptr< BackendInterface > backend, std::shared_ptr< feed::SubscriptionManagerInterface > subscriptions, std::shared_ptr< NetworkValidatedLedgersInterface > validatedLedgers, SourceFactory sourceFactory=makeSource)
	Create an instance of the load balancer.
std::vector< std::string >	loadInitialLedger (uint32_t sequence, bool cacheOnly=false, std::chrono::steady_clock::duration retryAfter=std::chrono::seconds{2})
	Load the initial ledger, writing data to the queue.
OptionalGetLedgerResponseType	fetchLedger (uint32_t ledgerSequence, bool getObjects, bool getObjectNeighbors, std::chrono::steady_clock::duration retryAfter=std::chrono::seconds{2})
	Fetch data for a specific ledger.
boost::json::value	toJson () const
	Represent the state of this load balancer as a JSON object.
std::expected< boost::json::object, rpc::ClioError >	forwardToRippled (boost::json::object const &request, std::optional< std::string > const &clientIp, bool isAdmin, boost::asio::yield_context yield)
	Forward a JSON RPC request to a randomly selected rippled node.
std::optional< ETLState >	getETLState () noexcept
	Return state of ETL nodes.
void	stop (boost::asio::yield_context yield)
	Stop the load balancer. This will stop all subscription sources.
Public Member Functions inherited from etl::LoadBalancerTag

Static Public Member Functions
static std::shared_ptr< LoadBalancer >	makeLoadBalancer (util::config::ClioConfigDefinition const &config, boost::asio::io_context &ioc, std::shared_ptr< BackendInterface > backend, std::shared_ptr< feed::SubscriptionManagerInterface > subscriptions, std::shared_ptr< NetworkValidatedLedgersInterface > validatedLedgers, SourceFactory sourceFactory=makeSource)
	A factory function for the load balancer.

Static Public Attributes
static constexpr std::string_view	kADMIN_FORWARDING_X_USER_VALUE = "clio_admin"
	Value for the X-User header when forwarding admin requests.
static constexpr std::string_view	kUSER_FORWARDING_X_USER_VALUE = "clio_user"
	Value for the X-User header when forwarding user requests.

Detailed Description

This class is used to manage connections to transaction processing processes.

This class spawns a listener for each etl source, which listens to messages on the ledgers stream (to keep track of which ledgers have been validated by the network, and the range of ledgers each etl source has). This class also allows requests for ledger data to be load balanced across all possible ETL sources.

Constructor & Destructor Documentation

LoadBalancer()

etl::LoadBalancer::LoadBalancer	(	util::config::ClioConfigDefinition const &	config,
		boost::asio::io_context &	ioc,
		std::shared_ptr< BackendInterface >	backend,
		std::shared_ptr< feed::SubscriptionManagerInterface >	subscriptions,
		std::shared_ptr< NetworkValidatedLedgersInterface >	validatedLedgers,
		SourceFactory	sourceFactory = makeSource )

Create an instance of the load balancer.

Parameters

config	The configuration to use
ioc	The io_context to run on
backend	BackendInterface implementation
subscriptions	Subscription manager
validatedLedgers	The network validated ledgers datastructure
sourceFactory	A factory function to create a source

Member Function Documentation

fetchLedger()

LoadBalancer::OptionalGetLedgerResponseType etl::LoadBalancer::fetchLedger	(	uint32_t	ledgerSequence,
		bool	getObjects,
		bool	getObjectNeighbors,
		std::chrono::steady_clock::duration	retryAfter = std::chrono::seconds{2} )

Fetch data for a specific ledger.

This function will continuously try to fetch data for the specified ledger until the fetch succeeds, the ledger is found in the database, or the server is shutting down.

Parameters

ledgerSequence	Sequence of the ledger to fetch
getObjects	Whether to get the account state diff between this ledger and the prior one
getObjectNeighbors	Whether to request object neighbors
retryAfter	Time to wait between retries (2 seconds by default)

Returns

The extracted data, if extraction was successful. If the ledger was found in the database or the server is shutting down, the optional will be empty

forwardToRippled()

std::expected< boost::json::object, rpc::ClioError > etl::LoadBalancer::forwardToRippled	(	boost::json::object const &	request,
		std::optional< std::string > const &	clientIp,
		bool	isAdmin,
		boost::asio::yield_context	yield )

Forward a JSON RPC request to a randomly selected rippled node.

Parameters

request	JSON-RPC request to forward
clientIp	The IP address of the peer, if known
isAdmin	Whether the request is from an admin
yield	The coroutine context

Returns

Response received from rippled node as JSON object on success or error on failure

getETLState()

std::optional< ETLState > etl::LoadBalancer::getETLState ( )

noexcept

Return state of ETL nodes.

Returns

ETL state, nullopt if etl nodes not available

loadInitialLedger()

std::vector< std::string > etl::LoadBalancer::loadInitialLedger	(	uint32_t	sequence,
		bool	cacheOnly = false,
		std::chrono::steady_clock::duration	retryAfter = std::chrono::seconds{2} )

Load the initial ledger, writing data to the queue.

Note

This function will retry indefinitely until the ledger is downloaded.

Parameters

sequence	Sequence of ledger to download
cacheOnly	Whether to only write to cache and not to the DB; defaults to false
retryAfter	Time to wait between retries (2 seconds by default)

Returns

A std::vector<std::string> The ledger data

makeLoadBalancer()

std::shared_ptr< LoadBalancer > etl::LoadBalancer::makeLoadBalancer ( util::config::ClioConfigDefinition const & config, boost::asio::io_context & ioc, std::shared_ptr< BackendInterface > backend, std::shared_ptr< feed::SubscriptionManagerInterface > subscriptions, std::shared_ptr< NetworkValidatedLedgersInterface > validatedLedgers, SourceFactory sourceFactory = makeSource )

static

A factory function for the load balancer.

Parameters

config	The configuration to use
ioc	The io_context to run on
backend	BackendInterface implementation
subscriptions	Subscription manager
validatedLedgers	The network validated ledgers datastructure
sourceFactory	A factory function to create a source

Returns

A shared pointer to a new instance of LoadBalancer

stop()

void etl::LoadBalancer::stop

(

boost::asio::yield_context

yield

)

Stop the load balancer. This will stop all subscription sources.

Note

This function will asynchronously wait for all sources to stop.

Parameters

yield

The coroutine context

toJson()

boost::json::value etl::LoadBalancer::toJson

(

)

const

Represent the state of this load balancer as a JSON object.

Returns

JSON representation of the state of this load balancer.

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

• /__w/clio/clio/src/etl/LoadBalancer.hpp
• /__w/clio/clio/src/etl/LoadBalancer.cpp