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Copy pathConnectionPool.cpp
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312 lines (280 loc) · 9.92 KB
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/* This file is part of VoltDB.
* Copyright (C) 2008-2016 VoltDB Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include "ConnectionPool.h"
#include <cassert>
#include <exception>
#include <iostream>
#include <boost/scoped_ptr.hpp>
#include <cstdio>
#include "InvocationResponse.hpp"
#include "ClientConfig.h"
namespace voltdb {
/*
* Global connection pool instance that is intialized when the library is loaded and deleted on unload
*/
static ConnectionPool *gPool;
/*
* A delegating listener that forwards to another listener that can be NULL. It is also possible to change
* the listener being delegated to on the fly.
*/
class DelegatingStatusListener : public StatusListener {
public:
StatusListener *m_listener;
bool m_connectionLost;
DelegatingStatusListener() : m_listener(NULL), m_connectionLost(false) {}
bool uncaughtException(
std::exception exception,
boost::shared_ptr<voltdb::ProcedureCallback> callback,
InvocationResponse response) {
if (m_listener != NULL) {
return m_listener->uncaughtException(exception, callback, response);
}
return false;
}
bool connectionLost(std::string hostname, int32_t connectionsLeft) {
m_connectionLost = true;
if (m_listener != NULL) {
bool retval = m_listener->connectionLost(hostname, connectionsLeft);
return retval;
}
return false;
}
bool connectionActive(std::string hostname, int32_t connectionsActive) {
if (m_listener != NULL) {
bool retval = m_listener->connectionActive(hostname, connectionsActive);
return retval;
} else {
return false;
}
}
bool backpressure(bool hasBackpressure) {
if (m_listener != NULL) {
return m_listener->backpressure(hasBackpressure);
}
return false;
}
};
/*
* A record for information associated with a client such as the delegating listener
* and identifier. This can be used to return the client to the ClientMap after a script exits.
*/
class ClientStuff {
public:
ClientStuff(
voltdb::Client client,
std::string identifier,
DelegatingStatusListener *listener) :
m_identifier(identifier), m_listener(listener), m_client(client)
{}
std::string m_identifier;
DelegatingStatusListener *m_listener;
voltdb::Client m_client;
};
/*
* Short hand for an exception safe lock acquisition
*/
class LockGuard {
public:
LockGuard(pthread_mutex_t &mutex) {
m_mutex = &mutex;
pthread_mutex_lock(m_mutex);
}
~LockGuard() {
pthread_mutex_unlock(m_mutex);
}
private:
pthread_mutex_t *m_mutex;
};
/*
* Cleanup function used by thread local ptr to a list of clients
* that were borrowed from the pool. It unsets the listener and returns the client
* to the pool.
*/
void cleanupOnScriptEnd(void *ptr) {
if (gPool != NULL) {
LockGuard guard(gPool->m_lock);
ClientSet *clients = reinterpret_cast<ClientSet*>(ptr);
if (clients != NULL) {
boost::scoped_ptr<ClientSet> guard(clients);
for(ClientSet::iterator i = clients->begin(); i != clients->end(); i++) {
(*i)->m_listener->m_listener = NULL;
gPool->m_clients[(*i)->m_identifier].push_back(*i);
}
pthread_setspecific(gPool->m_borrowedClients, NULL);
}
}
}
ConnectionPool::ConnectionPool() {
pthread_mutex_init(&m_lock, NULL);
pthread_key_create(&m_borrowedClients, &cleanupOnScriptEnd);
}
/*
* Destructor specifically deletes the thread local pointer because the cleanup method
* needs acess to the members of ConnectionPool.
*/
ConnectionPool::~ConnectionPool() {
pthread_mutex_destroy(&m_lock);
pthread_key_delete(m_borrowedClients);
}
/*
* Retrieve a client that is connected and authenticated
* to the specified hostname and port. Will reuse an existing connection if one is available.
*/
voltdb::Client
ConnectionPool::acquireClient(
std::string hostname,
std::string username,
std::string password,
StatusListener *listener,
unsigned short port,
ClientAuthHashScheme sha)
throw (voltdb::Exception, voltdb::ConnectException, voltdb::LibEventException) {
LockGuard guard(m_lock);
ClientSet *clients = reinterpret_cast<ClientSet*>(pthread_getspecific(m_borrowedClients));
if (clients == NULL) {
clients = new ClientSet();
pthread_setspecific( m_borrowedClients, static_cast<const void *>(clients));
}
char portBytes[16];
unsigned int portInt = port;
snprintf(portBytes, 16, "%d", portInt);
std::string identifier = hostname + "," + std::string(portBytes) + "," + username + "," + password;
// if a thread calls acquireClient() multiple times with the same identifier, reuse the same client
for (ClientSet::iterator i = clients->begin(); i != clients->end(); i++) {
if ((*i)->m_identifier == identifier) {
return (*i)->m_client;
}
}
std::vector<boost::shared_ptr<ClientStuff> > *clientStuffs = &m_clients[identifier];
while (clientStuffs->size() > 0) {
boost::shared_ptr<ClientStuff> clientStuff = clientStuffs->back();
clientStuffs->pop_back();
// run the event loop once to verify the connection is still available
clientStuff->m_client.runOnce();
if (clientStuff->m_listener->m_connectionLost) {
// if this connection is lost, try the next
continue;
} else {
// otherwise return this connection
clientStuff->m_listener->m_listener = listener;
clients->push_back(clientStuff);
return clientStuff->m_client;
}
}
// no connection available, make a new one
DelegatingStatusListener *delegatingListener = new DelegatingStatusListener();
Client client = voltdb::Client::create(ClientConfig( username, password, delegatingListener, sha));
client.createConnection(hostname, port);
boost::shared_ptr<ClientStuff> stuff(new ClientStuff(client, identifier, delegatingListener));
stuff->m_listener->m_listener = listener;
clients->push_back(stuff);
return client;
}
voltdb::Client
ConnectionPool::acquireClient(
std::string hostname,
std::string username,
std::string password,
unsigned short port,
ClientAuthHashScheme sha)
throw (voltdb::Exception, voltdb::ConnectException, voltdb::LibEventException) {
return acquireClient(hostname, username, password, NULL, port, sha);
}
void ConnectionPool::returnClient(Client client) throw (voltdb::Exception) {
LockGuard guard(m_lock);
ClientSet *clients = reinterpret_cast<ClientSet*>(pthread_getspecific(m_borrowedClients));
if (clients == NULL) {
throw MisplacedClientException();
}
for (ClientSet::iterator i = clients->begin(); i != clients->end(); i++) {
if ((*i)->m_client == client) {
(*i)->m_listener->m_listener = NULL;
m_clients[(*i)->m_identifier].push_back(*i);
clients->erase(i);
return;
}
}
throw MisplacedClientException();
}
void ConnectionPool::closeClientConnection(Client client) throw (voltdb::Exception) {
LockGuard guard(m_lock);
ClientSet *clients = reinterpret_cast<ClientSet*>(pthread_getspecific(m_borrowedClients));
if (clients == NULL) {
//No clients closing a stale object or not owned by this thread.
return;
}
for (ClientSet::iterator i = clients->begin(); i != clients->end(); i++) {
if ((*i)->m_client == client) {
client.close();
(*i)->m_listener->m_listener = NULL;
clients->erase(i);
return;
}
}
}
/*
* Return the number of clients held by this thread
*/
int ConnectionPool::numClientsBorrowed() {
ClientSet *clients = reinterpret_cast<ClientSet*>(pthread_getspecific(m_borrowedClients));
if (clients != NULL) {
return clients->size();
}
return 0;
}
/*
* Release any unreleased clients associated with this thread/script
*/
void ConnectionPool::onScriptEnd() {
cleanupOnScriptEnd(pthread_getspecific(m_borrowedClients));
}
/*
* Invoked by the external language/script environment when the library is loaded.
* Creates the connection pool
*/
void onLoad() {
assert(gPool == NULL);
gPool = new ConnectionPool();
}
/*
* Invoked by the external language/script environment when the library is unloaded.
* Deletes the connection pool closing all connections. Does not drain connections.
*/
void onUnload() {
assert(gPool != NULL);
delete gPool;
gPool = NULL;
}
/*
* Invoked by the external language/script environment when a script ends. Causes
* all connections acquired by this thread to be returned.
*/
void onScriptEnd() {
assert(gPool != NULL);
gPool->onScriptEnd();
}
voltdb::ConnectionPool* ConnectionPool::pool() {
assert(gPool != NULL);
return gPool;
}
}
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