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arangodb/lib/SimpleHttpClient/ConnectionManager.cpp

376 lines
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C++

////////////////////////////////////////////////////////////////////////////////
/// @brief manages open HTTP connections on the client side
///
/// @file ConnectionManager.cpp
///
/// DISCLAIMER
///
/// Copyright 2014 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Max Neunhoeffer
/// @author Copyright 2014, triagens GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#include "ConnectionManager.h"
#include "Basics/ReadLocker.h"
#include "Basics/WriteLocker.h"
using namespace std;
using namespace triagens::httpclient;
using namespace triagens::rest;
////////////////////////////////////////////////////////////////////////////////
/// @brief global options for connections
////////////////////////////////////////////////////////////////////////////////
ConnectionOptions ConnectionManager::_globalConnectionOptions = {
15.0, // connectTimeout
3.0, // requestTimeout
3, // numRetries
5.0, // singleRequestTimeout
0 // sslProtocol
};
////////////////////////////////////////////////////////////////////////////////
/// @brief singleton instance of the connection manager
////////////////////////////////////////////////////////////////////////////////
static ConnectionManager* Instance = nullptr;
////////////////////////////////////////////////////////////////////////////////
/// @brief destructor
////////////////////////////////////////////////////////////////////////////////
ConnectionManager::~ConnectionManager ( ) {
for (size_t i = 0; i < CONNECTION_MANAGER_BUCKETS; ++i) {
WRITE_LOCKER(_connectionsBuckets[i]._lock);
for (auto& it : _connectionsBuckets[i]._connections) {
delete it.second;
}
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief initialize the connection manager
////////////////////////////////////////////////////////////////////////////////
void ConnectionManager::initialize () {
Instance = new ConnectionManager();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief get the unique instance
////////////////////////////////////////////////////////////////////////////////
ConnectionManager* ConnectionManager::instance () {
return Instance;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief destructor for SingleServerConnection class
////////////////////////////////////////////////////////////////////////////////
ConnectionManager::SingleServerConnection::~SingleServerConnection () {
delete _connection;
delete _endpoint;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief destructor of ServerConnections class
////////////////////////////////////////////////////////////////////////////////
ConnectionManager::ServerConnections::~ServerConnections () {
WRITE_LOCKER(_lock);
for (auto& it : _connections) {
delete it;
}
_connections.clear();
_unused.clear();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief adds a single connection
////////////////////////////////////////////////////////////////////////////////
void ConnectionManager::ServerConnections::addConnection (ConnectionManager::SingleServerConnection* connection) {
WRITE_LOCKER(_lock);
_connections.emplace_back(connection);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief pop a free connection - returns nullptr if no connection is
/// available
////////////////////////////////////////////////////////////////////////////////
ConnectionManager::SingleServerConnection* ConnectionManager::ServerConnections::popConnection () {
// get an unused connection
{
WRITE_LOCKER(_lock);
if (! _unused.empty()) {
auto connection = _unused.back();
_unused.pop_back();
return connection;
}
}
return nullptr;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief push a unused connection back on the stack, allowing its re-use
////////////////////////////////////////////////////////////////////////////////
void ConnectionManager::ServerConnections::pushConnection (ConnectionManager::SingleServerConnection* connection) {
connection->_lastUsed = time(0);
WRITE_LOCKER(_lock);
_unused.emplace_back(connection);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief remove a (broken) connection from the list of connections
////////////////////////////////////////////////////////////////////////////////
void ConnectionManager::ServerConnections::removeConnection (ConnectionManager::SingleServerConnection* connection) {
WRITE_LOCKER(_lock);
for (auto it = _connections.begin(); it != _connections.end(); ++it) {
if ((*it) == connection) {
// got it, now remove it
_connections.erase(it);
return;
}
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief closes unused connections
////////////////////////////////////////////////////////////////////////////////
void ConnectionManager::ServerConnections::closeUnusedConnections (double limit) {
time_t const t = time(0);
std::list<ConnectionManager::SingleServerConnection*>::iterator current;
WRITE_LOCKER(_lock);
for (current = _unused.begin(); current != _unused.end(); /* no hoisting */) {
SingleServerConnection* connection = (*current);
if (t - connection->_lastUsed <= limit) {
// connection is still valid
++current;
}
else {
// connection is timed out
// remove from list of connections
for (auto it = _connections.begin(); it != _connections.end(); ++it) {
if ((*it) == connection) {
_connections.erase(it);
break;
}
}
delete connection;
current = _unused.erase(current);
}
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief open or get a previously cached connection to a server
////////////////////////////////////////////////////////////////////////////////
ConnectionManager::SingleServerConnection* ConnectionManager::leaseConnection (std::string const& endpoint) {
// first find a connections list
// this is optimized for the fact that we mostly have a connections
// list for an endpoint already
auto const slot = bucket(endpoint);
ServerConnections* s = nullptr;
{
READ_LOCKER(_connectionsBuckets[slot]._lock);
auto it = _connectionsBuckets[slot]._connections.find(endpoint);
if (it != _connectionsBuckets[slot]._connections.end()) {
s = (*it).second;
}
}
if (s == nullptr) {
// do not yet have a connections list for this endpoint, so let's create one!
std::unique_ptr<ServerConnections> sc(new ServerConnections());
sc->_connections.reserve(16);
// note that it is possible for a concurrent thread to have created
// a list for the same endpoint. this case is handled below
WRITE_LOCKER(_connectionsBuckets[slot]._lock);
auto it = _connectionsBuckets[slot]._connections.emplace(endpoint, sc.get());
if (! it.second) {
// insert didn't work -> another thread has concurrently created a
// list for the same endpoint
// this means the unique_ptr can free the just created object and
// we only need to lookup the connections list from the map
auto it2 = _connectionsBuckets[slot]._connections.find(endpoint);
// we must have a result!
TRI_ASSERT(it2 != _connectionsBuckets[slot]._connections.end());
s = (*it2).second;
}
else {
// insert has worked. the map is now responsible for managing the
// connections list memory
s = sc.release();
}
}
// when we get here, we must have found a collections list
TRI_ASSERT(s != nullptr);
// now get an unused one
{
auto connection = s->popConnection();
if (connection != nullptr) {
return connection;
}
}
// create a new connection object
// create an endpoint object
std::unique_ptr<Endpoint> ep(Endpoint::clientFactory(endpoint));
if (ep == nullptr) {
// out memory
return nullptr;
}
// create a connection object
std::unique_ptr<GeneralClientConnection> cn(GeneralClientConnection::factory(
ep.get(),
_globalConnectionOptions._requestTimeout,
_globalConnectionOptions._connectTimeout,
_globalConnectionOptions._connectRetries,
_globalConnectionOptions._sslProtocol
));
if (cn == nullptr) {
// out of memory
return nullptr;
}
if (! cn->connect()) {
// could not connect
return nullptr;
}
// finally create the SingleServerConnection
std::unique_ptr<SingleServerConnection> c(new SingleServerConnection(s, cn.get(), ep.get(), endpoint));
if (c == nullptr) {
return nullptr;
}
// Now put it into our administration:
s->addConnection(c.get());
// now the ServerConnections list is responsible for the memory management!
cn.release();
ep.release();
return c.release();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief return leased connection to a server
////////////////////////////////////////////////////////////////////////////////
void ConnectionManager::returnConnection (SingleServerConnection* connection) {
if (! connection->_connection->isConnected()) {
brokenConnection(connection);
return;
}
auto manager = connection->_connections;
TRI_ASSERT(manager != nullptr);
manager->pushConnection(connection);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief report a leased connection as being broken
////////////////////////////////////////////////////////////////////////////////
void ConnectionManager::brokenConnection (SingleServerConnection* connection) {
auto manager = connection->_connections;
TRI_ASSERT(manager != nullptr);
manager->removeConnection(connection);
delete connection;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief closes all connections that have been unused for more than
/// limit seconds
////////////////////////////////////////////////////////////////////////////////
void ConnectionManager::closeUnusedConnections (double limit) {
// copy the list of ServerConnections first
std::vector<ConnectionManager::ServerConnections*> copy;
{
for (size_t i = 0; i < CONNECTION_MANAGER_BUCKETS; ++i) {
READ_LOCKER(_connectionsBuckets[i]._lock);
for (auto& it : _connectionsBuckets[i]._connections) {
copy.emplace_back(it.second);
}
}
}
// now perform the cleanup for each ServerConnections object
for (auto& it : copy) {
it->closeUnusedConnections(limit);
}
}
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