92 lines
2.6 KiB
C++
92 lines
2.6 KiB
C++
// @file
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/*
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* Copyright (C) 2010 10gen Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License, version 3,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <map>
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#include "../../client/dbclient.h"
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namespace mongo {
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/** here we keep a single connection (with reconnect) for a set of hosts,
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one each, and allow one user at a time per host. if in use already for that
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host, we block. so this is an easy way to keep a 1-deep pool of connections
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that many threads can share.
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thread-safe.
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Example:
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{
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ScopedConn c("foo.acme.com:9999");
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c->runCommand(...);
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}
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throws exception on connect error (but fine to try again later with a new
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scopedconn object for same host).
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*/
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class ScopedConn {
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public:
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/** throws assertions if connect failure etc. */
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ScopedConn(string hostport);
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~ScopedConn();
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DBClientConnection* operator->();
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private:
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auto_ptr<scoped_lock> connLock;
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static mutex mapMutex;
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struct X {
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mutex z;
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DBClientConnection cc;
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X() : cc(/*reconnect*/true, 0, /*timeout*/10) {
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cc._logLevel = 2;
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}
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} *x;
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typedef map<string,ScopedConn::X*> M;
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static M& _map;
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};
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inline ScopedConn::ScopedConn(string hostport) {
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bool first = false;
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{
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scoped_lock lk(mapMutex);
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x = _map[hostport];
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if( x == 0 ) {
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x = _map[hostport] = new X();
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first = true;
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connLock.reset( new scoped_lock(x->z) );
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}
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}
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if( !first ) {
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connLock.reset( new scoped_lock(x->z) );
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return;
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}
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// we already locked above...
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string err;
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x->cc.connect(hostport, err);
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}
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inline ScopedConn::~ScopedConn() {
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// conLock releases...
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}
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inline DBClientConnection* ScopedConn::operator->() {
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return &x->cc;
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}
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}
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