This is the implementation of LeaderRPCBase that uses the RPC system. More...

#include <LeaderRPC.h>

Inheritance diagram for LogCabin::Client::LeaderRPC:

Classes
class	Call
	See LeaderRPCBase::Call. More...
Public Member Functions
	LeaderRPC (const RPC::Address &hosts, SessionManager::ClusterUUID &clusterUUID, Backoff &sessionCreationBackoff, SessionManager &sessionManager)
	Constructor.
	~LeaderRPC ()
	Destructor.
Status	call (OpCode opCode, const google::protobuf::Message &request, google::protobuf::Message &response, TimePoint timeout)
	See LeaderRPCBase::call.
std::unique_ptr < LeaderRPCBase::Call >	makeCall ()
	See LeaderRPCBase::makeCall().
Private Member Functions
std::shared_ptr < RPC::ClientSession >	getSession (TimePoint timeout)
	Return a session connected to the most likely cluster leader, creating it if necessary.
void	reportFailure (std::shared_ptr< RPC::ClientSession > cachedSession)
	Notify this class that an RPC on the given session failed.
void	reportNotLeader (std::shared_ptr< RPC::ClientSession > cachedSession)
	Notify this class that a non-leader server rejected an RPC.
void	reportRedirect (std::shared_ptr< RPC::ClientSession > cachedSession, const std::string &host)
	Notify this class that an RPC on the given session was redirected by a non-leader server.
void	reportSuccess (std::shared_ptr< RPC::ClientSession > cachedSession)
	Notify this class that an RPC on the given session reached a leader.
Private Attributes
SessionManager::ClusterUUID &	clusterUUID
	Keeps track of the unique ID for this cluster, if known.
Backoff &	sessionCreationBackoff
	Used to rate-limit the creation of ClientSession objects (TCP connections).
SessionManager &	sessionManager
	Used to create new sessions.
std::mutex	mutex
	Protects all of the following member variables in this class.
bool	isConnecting
	Set to true when some thread is already initiating a new session.
Core::ConditionVariable	connected
	Notified when isConnecting becomes false (when leaderSession is set).
RPC::Address	hosts
	An address referring to the hosts in the LogCabin cluster.
std::string	leaderHint
	If nonempty, the address of the server that is likely to be the current leader.
std::shared_ptr < RPC::ClientSession >	leaderSession
	The goal is to get this session connected to the cluster leader.
uint64_t	failuresSinceLastSuccess
	The number of attempted RPCs that have not successfully reached a leader since the last time an RPC did.

Detailed Description

This is the implementation of LeaderRPCBase that uses the RPC system.

(The other implementation, LeaderRPCMock, is only used for testing.)

Definition at line 224 of file LeaderRPC.h.

Constructor & Destructor Documentation

LogCabin::Client::LeaderRPC::LeaderRPC	(	const RPC::Address &	hosts,
		SessionManager::ClusterUUID &	clusterUUID,
		Backoff &	sessionCreationBackoff,
		SessionManager &	sessionManager
	)

Constructor.

Parameters:

hosts	Describe the servers to connect to. This class assumes that refreshing 'hosts' will result in a random host that might be the current cluster leader.
clusterUUID	Keeps track of the unique ID for this cluster, if known.
sessionCreationBackoff	Used to rate-limit new TCP connections.
sessionManager	Used to create new sessions.

Definition at line 159 of file LeaderRPC.cc.

LogCabin::Client::LeaderRPC::~LeaderRPC ( )

Destructor.

Definition at line 176 of file LeaderRPC.cc.

Member Function Documentation

LeaderRPC::Status LogCabin::Client::LeaderRPC::call	(	OpCode	opCode,
		const google::protobuf::Message &	request,
		google::protobuf::Message &	response,
		TimePoint	timeout
	)		`[virtual]`

See LeaderRPCBase::call.

Implements LogCabin::Client::LeaderRPCBase.

Definition at line 182 of file LeaderRPC.cc.

std::unique_ptr< LeaderRPCBase::Call > LogCabin::Client::LeaderRPC::makeCall ( ) [virtual]

See LeaderRPCBase::makeCall().

Implements LogCabin::Client::LeaderRPCBase.

Definition at line 205 of file LeaderRPC.cc.

std::shared_ptr< RPC::ClientSession > LogCabin::Client::LeaderRPC::getSession ( TimePoint timeout ) [private]

Return a session connected to the most likely cluster leader, creating it if necessary.

Parameters:

timeout After this time has elapsed, stop trying to initiate the connection and return an invalid session.

Returns:: Session on which to execute RPCs.

Definition at line 211 of file LeaderRPC.cc.

void LogCabin::Client::LeaderRPC::reportFailure ( std::shared_ptr< RPC::ClientSession > cachedSession ) [private]

Notify this class that an RPC on the given session failed.

This will usually cause this class to connect to a random server next time getSession() is called.

Parameters:

cachedSession Session previously returned by getSession(). This is used to detect races in which some other thread has already solved the problem.

Definition at line 284 of file LeaderRPC.cc.

void LogCabin::Client::LeaderRPC::reportNotLeader ( std::shared_ptr< RPC::ClientSession > cachedSession ) [private]

Notify this class that a non-leader server rejected an RPC.

This will usually cause this class to connect to a random server next time getSession() is called.

Parameters:

cachedSession Session previously returned by getSession(). This is used to detect races in which some other thread has already solved the problem.

Definition at line 305 of file LeaderRPC.cc.

void LogCabin::Client::LeaderRPC::reportRedirect	(	std::shared_ptr< RPC::ClientSession >	cachedSession,
		const std::string &	host
	)		`[private]`

Notify this class that an RPC on the given session was redirected by a non-leader server.

This will usually cause this class to connect to the given host the next time getSession() is called.

Parameters:

cachedSession	Session previously returned by getSession(). This is used to detect races in which some other thread has already solved the problem.
host	Address of the server that is likely the leader.

Definition at line 326 of file LeaderRPC.cc.

void LogCabin::Client::LeaderRPC::reportSuccess ( std::shared_ptr< RPC::ClientSession > cachedSession ) [private]

Notify this class that an RPC on the given session reached a leader.

This is just here for debug log messages.

Parameters:

cachedSession Session previously returned by getSession(). This is used to detect races in which some other thread has already solved any problems.

Definition at line 351 of file LeaderRPC.cc.