path: root/db/repl/rs.cpp

/**
*    Copyright (C) 2008 10gen Inc.
*
*    This program is free software: you can redistribute it and/or  modify
*    it under the terms of the GNU Affero General Public License, version 3,
*    as published by the Free Software Foundation.
*
*    This program is distributed in the hope that it will be useful,
*    but WITHOUT ANY WARRANTY; without even the implied warranty of
*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*    GNU Affero General Public License for more details.
*
*    You should have received a copy of the GNU Affero General Public License
*    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "pch.h"
#include "../cmdline.h"
#include "../../util/sock.h"
#include "../client.h"
#include "../../client/dbclient.h"
#include "../dbhelpers.h"
#include "rs.h"
#include "connections.h"

namespace mongo { 

    using namespace bson;

    bool replSet = false;
    ReplSet *theReplSet = 0;
    extern string *discoveredSeed;

    void ReplSetImpl::sethbmsg(string s, int logLevel) { 
        static time_t lastLogged;
        _hbmsgTime = time(0);

        if( s == _hbmsg ) { 
            // unchanged
            if( _hbmsgTime - lastLogged < 60 )
                return;
        }

        unsigned sz = s.size();
        if( sz >= 256 ) 
            memcpy(_hbmsg, s.c_str(), 255);
        else {
            _hbmsg[sz] = 0;
            memcpy(_hbmsg, s.c_str(), sz);
        }
        if( !s.empty() ) {
            lastLogged = _hbmsgTime;
            log(logLevel) << "replSet " << s << rsLog;
        }
    }

    void ReplSetImpl::assumePrimary() { 
        assert( iAmPotentiallyHot() );
        writelock lk("admin."); // so we are synchronized with _logOp()
        box.setSelfPrimary(_self);
        //log() << "replSet PRIMARY" << rsLog; // self (" << _self->id() << ") is now primary" << rsLog;
    }

    void ReplSetImpl::changeState(MemberState s) { box.change(s, _self); }

    const bool closeOnRelinquish = true;

    void ReplSetImpl::relinquish() { 
        if( box.getState().primary() ) {
            log() << "replSet relinquishing primary state" << rsLog;
            changeState(MemberState::RS_SECONDARY);
            
            if( closeOnRelinquish ) {
                /* close sockets that were talking to us so they don't blithly send many writes that will fail
                   with "not master" (of course client could check result code, but in case they are not)
                */
                log() << "replSet closing client sockets after reqlinquishing primary" << rsLog;
                MessagingPort::closeAllSockets(1);
            }
        }
        else if( box.getState().startup2() ) {
            // ? add comment
            changeState(MemberState::RS_RECOVERING);
        }
    }

    /* look freshly for who is primary - includes relinquishing ourself. */
    void ReplSetImpl::forgetPrimary() { 
        if( box.getState().primary() ) 
            relinquish();
        else {
            box.setOtherPrimary(0);
        }
    }

    // for the replSetStepDown command
    bool ReplSetImpl::_stepDown(int secs) { 
        lock lk(this);
        if( box.getState().primary() ) { 
            elect.steppedDown = time(0) + secs;
            log() << "replSet info stepping down as primary secs=" << secs << rsLog;
            relinquish();
            return true;
        }
        return false;
    }

    bool ReplSetImpl::_freeze(int secs) { 
        lock lk(this);
        /* note if we are primary we remain primary but won't try to elect ourself again until 
           this time period expires. 
           */
        if( secs == 0 ) { 
            elect.steppedDown = 0;
            log() << "replSet info 'unfreezing'" << rsLog;
        }
        else {
            if( !box.getState().primary() ) { 
                elect.steppedDown = time(0) + secs;
                log() << "replSet info 'freezing' for " << secs << " seconds" << rsLog;
            }
            else {
                log() << "replSet info received freeze command but we are primary" << rsLog;
            }
        }
        return true;
    }

    void ReplSetImpl::msgUpdateHBInfo(HeartbeatInfo h) { 
        for( Member *m = _members.head(); m; m=m->next() ) {
            if( m->id() == h.id() ) {
                m->_hbinfo = h;
                return;
            }
        }
    }

    list<HostAndPort> ReplSetImpl::memberHostnames() const { 
        list<HostAndPort> L;
        L.push_back(_self->h());
        for( Member *m = _members.head(); m; m = m->next() )
            L.push_back(m->h());
        return L;
    }

    void ReplSetImpl::_fillIsMasterHost(const Member *m, vector<string>& hosts, vector<string>& passives, vector<string>& arbiters) {
        assert( m );
        if( m->config().hidden )
            return;

        if( m->potentiallyHot() ) {
            hosts.push_back(m->h().toString());
        }
        else if( !m->config().arbiterOnly ) {
            if( m->config().slaveDelay ) {
                /* hmmm - we don't list these as they are stale. */   
            } else {
                passives.push_back(m->h().toString());
            }
        }
        else {
            arbiters.push_back(m->h().toString());
        }
    }

    void ReplSetImpl::_fillIsMaster(BSONObjBuilder& b) {
        const StateBox::SP sp = box.get();
        bool isp = sp.state.primary();
        b.append("setName", name());
        b.append("ismaster", isp);
        b.append("secondary", sp.state.secondary());
        {
            vector<string> hosts, passives, arbiters;
            _fillIsMasterHost(_self, hosts, passives, arbiters);

            for( Member *m = _members.head(); m; m = m->next() ) {
                assert( m );
                _fillIsMasterHost(m, hosts, passives, arbiters);
            }

            if( hosts.size() > 0 ) {
                b.append("hosts", hosts);
            }
            if( passives.size() > 0 ) {
                b.append("passives", passives);
            }
            if( arbiters.size() > 0 ) {
                b.append("arbiters", arbiters);
            }
        }

        if( !isp ) { 
            const Member *m = sp.primary;
            if( m )
                b.append("primary", m->h().toString());
        }
        if( myConfig().arbiterOnly )
            b.append("arbiterOnly", true);
        if( myConfig().priority == 0 )
            b.append("passive", true);
        if( myConfig().slaveDelay )
            b.append("slaveDelay", myConfig().slaveDelay);
        if( myConfig().hidden )
            b.append("hidden", true);
        if( !myConfig().buildIndexes )
            b.append("buildIndexes", false);
    }

    /** @param cfgString <setname>/<seedhost1>,<seedhost2> */

    void parseReplsetCmdLine(string cfgString, string& setname, vector<HostAndPort>& seeds, set<HostAndPort>& seedSet ) { 
        const char *p = cfgString.c_str(); 
        const char *slash = strchr(p, '/');
        if( slash )
            setname = string(p, slash-p);
        else
            setname = p;
        uassert(13093, "bad --replSet config string format is: <setname>[/<seedhost1>,<seedhost2>,...]", !setname.empty());

        if( slash == 0 )
            return;

        p = slash + 1;
        while( 1 ) {
            const char *comma = strchr(p, ',');
            if( comma == 0 ) comma = strchr(p,0);
            if( p == comma )
                break;
            {
                HostAndPort m;
                try {
                    m = HostAndPort( string(p, comma-p) );
                }
                catch(...) {
                    uassert(13114, "bad --replSet seed hostname", false);
                }
                uassert(13096, "bad --replSet command line config string - dups?", seedSet.count(m) == 0 );
                seedSet.insert(m);
                //uassert(13101, "can't use localhost in replset host list", !m.isLocalHost());
                if( m.isSelf() ) {
                    log(1) << "replSet ignoring seed " << m.toString() << " (=self)" << rsLog;
                } else
                    seeds.push_back(m);
                if( *comma == 0 )
                    break;
                p = comma + 1;
            }
        }
    }

    ReplSetImpl::ReplSetImpl(ReplSetCmdline& replSetCmdline) : elect(this), 
        _self(0), 
        mgr( new Manager(this) )
    {
        _cfg = 0;
        memset(_hbmsg, 0, sizeof(_hbmsg));
        *_hbmsg = '.'; // temp...just to see
        lastH = 0;
        changeState(MemberState::RS_STARTUP);

        _seeds = &replSetCmdline.seeds;
        //for( vector<HostAndPort>::iterator i = seeds->begin(); i != seeds->end(); i++ )
        //    addMemberIfMissing(*i);

        log(1) << "replSet beginning startup..." << rsLog;

        loadConfig();

        unsigned sss = replSetCmdline.seedSet.size();
        for( Member *m = head(); m; m = m->next() ) {
            replSetCmdline.seedSet.erase(m->h());
        }
        for( set<HostAndPort>::iterator i = replSetCmdline.seedSet.begin(); i != replSetCmdline.seedSet.end(); i++ ) {
            if( i->isSelf() ) {
                if( sss == 1 ) 
                    log(1) << "replSet warning self is listed in the seed list and there are no other seeds listed did you intend that?" << rsLog;
            } else
                log() << "replSet warning command line seed " << i->toString() << " is not present in the current repl set config" << rsLog;
        }
    }

    void newReplUp();

    void ReplSetImpl::loadLastOpTimeWritten() { 
        //assert( lastOpTimeWritten.isNull() );
        readlock lk(rsoplog);
        BSONObj o;
        if( Helpers::getLast(rsoplog, o) ) { 
            lastH = o["h"].numberLong();
            lastOpTimeWritten = o["ts"]._opTime();
            uassert(13290, "bad replSet oplog entry?", !lastOpTimeWritten.isNull());
        }
    }

    /* call after constructing to start - returns fairly quickly after launching its threads */
    void ReplSetImpl::_go() { 
        try { 
            loadLastOpTimeWritten();
        }
        catch(std::exception& e) { 
            log() << "replSet error fatal couldn't query the local " << rsoplog << " collection.  Terminating mongod after 30 seconds." << rsLog;
            log() << e.what() << rsLog;
            sleepsecs(30);
            dbexit( EXIT_REPLICATION_ERROR );
            return;
        }

        changeState(MemberState::RS_STARTUP2);
        startThreads();
        newReplUp(); // oplog.cpp
    }

    ReplSetImpl::StartupStatus ReplSetImpl::startupStatus = PRESTART;
    string ReplSetImpl::startupStatusMsg;

    extern BSONObj *getLastErrorDefault;

    void ReplSetImpl::setSelfTo(Member *m) {
        _self = m;
        if( m ) _buildIndexes = m->config().buildIndexes;
        else _buildIndexes = true;
    }

    /** @param reconf true if this is a reconfiguration and not an initial load of the configuration.
        @return true if ok; throws if config really bad; false if config doesn't include self
    */
    bool ReplSetImpl::initFromConfig(ReplSetConfig& c, bool reconf) {
        /* NOTE: haveNewConfig() writes the new config to disk before we get here.  So 
                 we cannot error out at this point, except fatally.  Check errors earlier.
                 */
        lock lk(this);

        if( getLastErrorDefault || !c.getLastErrorDefaults.isEmpty() ) {
            // see comment in dbcommands.cpp for getlasterrordefault
            getLastErrorDefault = new BSONObj( c.getLastErrorDefaults );
        }

        list<const ReplSetConfig::MemberCfg*> newOnes;
        bool additive = reconf;
        {
            unsigned nfound = 0;
            int me = 0;
            for( vector<ReplSetConfig::MemberCfg>::iterator i = c.members.begin(); i != c.members.end(); i++ ) { 
                const ReplSetConfig::MemberCfg& m = *i;
                if( m.h.isSelf() ) {
                    nfound++;
                    me++;
                    if( !reconf || (_self && _self->id() == (unsigned) m._id) )
                        ;
                    else { 
                        log() << "replSet " << _self->id() << ' ' << m._id << rsLog;
                        assert(false);
                    }
                }
                else if( reconf ) { 
                    const Member *old = findById(m._id);
                    if( old ) { 
                        nfound++;
                        assert( (int) old->id() == m._id );
                        if( old->config() == m ) { 
                            additive = false;
                        }
                    }
                    else {
                        newOnes.push_back(&m);
                    }
                }
                
                // change timeout settings, if necessary
                ScopedConn conn(m.h.toString());
                conn.setTimeout(c.ho.heartbeatTimeoutMillis/1000.0);
            }
            if( me == 0 ) {
                // log() << "replSet config : " << _cfg->toString() << rsLog;
                log() << "replSet error self not present in the repl set configuration:" << rsLog;
                log() << c.toString() << rsLog;
                uasserted(13497, "replSet error self not present in the configuration");
            }
            uassert( 13302, "replSet error self appears twice in the repl set configuration", me<=1 );

            if( reconf && config().members.size() != nfound ) 
                additive = false;
        }

        _cfg = new ReplSetConfig(c);
        assert( _cfg->ok() );
        assert( _name.empty() || _name == _cfg->_id );
        _name = _cfg->_id;
        assert( !_name.empty() );

        if( additive ) { 
            log() << "replSet info : additive change to configuration" << rsLog;
            for( list<const ReplSetConfig::MemberCfg*>::const_iterator i = newOnes.begin(); i != newOnes.end(); i++ ) {
                const ReplSetConfig::MemberCfg* m = *i;
                Member *mi = new Member(m->h, m->_id, m, false);

                /** we will indicate that new members are up() initially so that we don't relinquish our 
                    primary state because we can't (transiently) see a majority.  they should be up as we 
                    check that new members are up before getting here on reconfig anyway.
                    */
                mi->get_hbinfo().health = 0.1;

                _members.push(mi);
                startHealthTaskFor(mi);
            }
            return true;
        }

        // start with no members.  if this is a reconfig, drop the old ones.
        _members.orphanAll();

        endOldHealthTasks();

        int oldPrimaryId = -1;
        {
            const Member *p = box.getPrimary();
            if( p ) 
                oldPrimaryId = p->id();
        }
        forgetPrimary();
        
        bool iWasArbiterOnly = _self ? iAmArbiterOnly() : false;
        setSelfTo(0);
        for( vector<ReplSetConfig::MemberCfg>::iterator i = _cfg->members.begin(); i != _cfg->members.end(); i++ ) { 
            const ReplSetConfig::MemberCfg& m = *i;
            Member *mi;
            if( m.h.isSelf() ) {
                assert( _self == 0 );
                mi = new Member(m.h, m._id, &m, true);
                setSelfTo(mi);

                // if the arbiter status changed
                if (iWasArbiterOnly ^ iAmArbiterOnly()) {
                    _changeArbiterState();
                }
                
                if( (int)mi->id() == oldPrimaryId )
                    box.setSelfPrimary(mi);
            } else {
                mi = new Member(m.h, m._id, &m, false);
                _members.push(mi);
                startHealthTaskFor(mi);
                if( (int)mi->id() == oldPrimaryId )
                    box.setOtherPrimary(mi);
            }
        }
        return true;
    }

    void startSyncThread();

    void ReplSetImpl::_changeArbiterState() {
        if (iAmArbiterOnly()) {
            changeState(MemberState::RS_ARBITER);

            // if there is an oplog, free it
            // not sure if this is necessary, maybe just leave the oplog and let
            // the user delete it if they want the space?
            writelock lk(rsoplog);
            Client::Context c(rsoplog, dbpath, 0, false);
            NamespaceDetails *d = nsdetails(rsoplog);
            if (d) {
                string errmsg;
                bob res;
                dropCollection(rsoplog, errmsg, res);

                // clear last op time to force initial sync (if the arbiter
                // becomes a "normal" server again)
                lastOpTimeWritten = OpTime();
            }
        }
        else {
            changeState(MemberState::RS_RECOVERING);

            // oplog will be allocated when sync begins     
            /* TODO : could this cause two sync threads to exist (race condition)? */
            boost::thread t(startSyncThread);
        }
    }

    // Our own config must be the first one.
    bool ReplSetImpl::_loadConfigFinish(vector<ReplSetConfig>& cfgs) { 
        int v = -1;
        ReplSetConfig *highest = 0;
        int myVersion = -2000;
        int n = 0;
        for( vector<ReplSetConfig>::iterator i = cfgs.begin(); i != cfgs.end(); i++ ) { 
            ReplSetConfig& cfg = *i;
            if( ++n == 1 ) myVersion = cfg.version;
            if( cfg.ok() && cfg.version > v ) { 
                highest = &cfg;
                v = cfg.version;
            }
        }
        assert( highest );

        if( !initFromConfig(*highest) ) 
            return false;

        if( highest->version > myVersion && highest->version >= 0 ) { 
            log() << "replSet got config version " << highest->version << " from a remote, saving locally" << rsLog;
            writelock lk("admin.");
            highest->saveConfigLocally(BSONObj());
        }
        return true;
    }

    void ReplSetImpl::loadConfig() {
        while( 1 ) {
            startupStatus = LOADINGCONFIG;
            startupStatusMsg = "loading " + rsConfigNs + " config (LOADINGCONFIG)";
            try {
                vector<ReplSetConfig> configs;
                try { 
                    configs.push_back( ReplSetConfig(HostAndPort::me()) );
                }
                catch(DBException& e) {
                    log() << "replSet exception loading our local replset configuration object : " << e.toString() << rsLog;
                    throw;
                }
                for( vector<HostAndPort>::const_iterator i = _seeds->begin(); i != _seeds->end(); i++ ) {
                    try { 
                        configs.push_back( ReplSetConfig(*i) );
                    }
                    catch( DBException& e ) { 
                        log() << "replSet exception trying to load config from " << *i << " : " << e.toString() << rsLog;
                    }
                }

                if( discoveredSeed ) { 
                    try {
                        configs.push_back( ReplSetConfig(HostAndPort(*discoveredSeed)) );
                    }
                    catch( DBException& ) { 
                        log(1) << "replSet exception trying to load config from discovered seed " << *discoveredSeed << rsLog;
                    }
                }

                int nok = 0;
                int nempty = 0;
                for( vector<ReplSetConfig>::iterator i = configs.begin(); i != configs.end(); i++ ) { 
                    if( i->ok() )
                        nok++;
                    if( i->empty() )
                        nempty++;
                }
                if( nok == 0 ) {

                    if( nempty == (int) configs.size() ) {
                        startupStatus = EMPTYCONFIG;
                        startupStatusMsg = "can't get " + rsConfigNs + " config from self or any seed (EMPTYCONFIG)";
                        log() << "replSet can't get " << rsConfigNs << " config from self or any seed (EMPTYCONFIG)" << rsLog;
                        static unsigned once;
                        if( ++once == 1 ) 
                            log() << "replSet info you may need to run replSetInitiate -- rs.initiate() in the shell -- if that is not already done" << rsLog;
                        if( _seeds->size() == 0 )
                            log(1) << "replSet info no seed hosts were specified on the --replSet command line" << rsLog;
                    }
                    else {
                        startupStatus = EMPTYUNREACHABLE;
                        startupStatusMsg = "can't currently get " + rsConfigNs + " config from self or any seed (EMPTYUNREACHABLE)";
                        log() << "replSet can't get " << rsConfigNs << " config from self or any seed (yet)" << rsLog;
                    }

                    sleepsecs(10);
                    continue;
                }

                if( !_loadConfigFinish(configs) ) { 
                    log() << "replSet info Couldn't load config yet. Sleeping 20sec and will try again." << rsLog;
                    sleepsecs(20);
                    continue;
                }
            }
            catch(DBException& e) { 
                startupStatus = BADCONFIG;
                startupStatusMsg = "replSet error loading set config (BADCONFIG)";
                log() << "replSet error loading configurations " << e.toString() << rsLog;
                log() << "replSet error replication will not start" << rsLog;
                sethbmsg("error loading set config");
                _fatal();
                throw;
            }
            break;
        }
        startupStatusMsg = "? started";
        startupStatus = STARTED;
    }

    void ReplSetImpl::_fatal() 
    { 
        //lock l(this);
        box.set(MemberState::RS_FATAL, 0);
        //sethbmsg("fatal error");
        log() << "replSet error fatal, stopping replication" << rsLog; 
    }

    void ReplSet::haveNewConfig(ReplSetConfig& newConfig, bool addComment) { 
        lock l(this); // convention is to lock replset before taking the db rwlock
        writelock lk("");
        bo comment;
        if( addComment )
            comment = BSON( "msg" << "Reconfig set" << "version" << newConfig.version );
        newConfig.saveConfigLocally(comment);
        try { 
            initFromConfig(newConfig, true);
            log() << "replSet replSetReconfig new config saved locally" << rsLog;
        }
        catch(DBException& e) {
            if( e.getCode() == 13497 /* removed from set */ ) {
                cc().shutdown();
                dbexit( EXIT_CLEAN , "removed from replica set" ); // never returns
                assert(0);
            }
            log() << "replSet error unexpected exception in haveNewConfig() : " << e.toString() << rsLog;
            _fatal();
        }
        catch(...) { 
            log() << "replSet error unexpected exception in haveNewConfig()" << rsLog;
            _fatal();
        }
    }

    void Manager::msgReceivedNewConfig(BSONObj o) {
        log() << "replset msgReceivedNewConfig version: " << o["version"].toString() << rsLog;
        ReplSetConfig c(o);
        if( c.version > rs->config().version )
            theReplSet->haveNewConfig(c, false);
        else { 
            log() << "replSet info msgReceivedNewConfig but version isn't higher " << 
                c.version << ' ' << rs->config().version << rsLog;
        }
    }

    /* forked as a thread during startup 
       it can run quite a while looking for config.  but once found, 
       a separate thread takes over as ReplSetImpl::Manager, and this thread
       terminates.
    */
    void startReplSets(ReplSetCmdline *replSetCmdline) {
        Client::initThread("startReplSets");
        try { 
            assert( theReplSet == 0 );
            if( replSetCmdline == 0 ) {
                assert(!replSet);
                return;
            }
            if( !noauth ) {
                cc().getAuthenticationInfo()->authorize("local");
            }
            (theReplSet = new ReplSet(*replSetCmdline))->go();
        }
        catch(std::exception& e) { 
            log() << "replSet caught exception in startReplSets thread: " << e.what() << rsLog;
            if( theReplSet ) 
                theReplSet->fatal();
        }
        cc().shutdown();
    }

}

namespace boost { 

    void assertion_failed(char const * expr, char const * function, char const * file, long line)
    {
        mongo::log() << "boost assertion failure " << expr << ' ' << function << ' ' << file << ' ' << line << endl;
    }

}