// get_last_error.cpp
/**
* Copyright (C) 2013 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 .
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/db/commands/get_last_error.h"
#include "mongo/db/client.h"
#include "mongo/db/curop.h"
#include "mongo/db/commands.h"
#include "mongo/db/field_parser.h"
#include "mongo/db/lasterror.h"
#include "mongo/db/repl/rs.h"
#include "mongo/db/write_concern.h"
namespace mongo {
/* reset any errors so that getlasterror comes back clean.
useful before performing a long series of operations where we want to
see if any of the operations triggered an error, but don't want to check
after each op as that woudl be a client/server turnaround.
*/
class CmdResetError : public Command {
public:
virtual bool isWriteCommandForConfigServer() const { return false; }
virtual bool slaveOk() const {
return true;
}
virtual void addRequiredPrivileges(const std::string& dbname,
const BSONObj& cmdObj,
std::vector* out) {} // No auth required
virtual void help( stringstream& help ) const {
help << "reset error state (used with getpreverror)";
}
CmdResetError() : Command("resetError", false, "reseterror") {}
bool run(OperationContext* txn, const string& db, BSONObj& cmdObj, int, string& errmsg, BSONObjBuilder& result, bool fromRepl) {
LastError *le = lastError.get();
verify( le );
le->reset();
return true;
}
} cmdResetError;
/* set by replica sets if specified in the configuration.
a pointer is used to avoid any possible locking issues with lockless reading.
(for now, it simply orphans any old copy as config changes should be extremely rare).
note: once non-null, never goes to null again.
*/
BSONObj *getLastErrorDefault = 0;
class CmdGetLastError : public Command {
public:
CmdGetLastError() : Command("getLastError", false, "getlasterror") { }
virtual bool isWriteCommandForConfigServer() const { return false; }
virtual bool slaveOk() const { return true; }
virtual void addRequiredPrivileges(const std::string& dbname,
const BSONObj& cmdObj,
std::vector* out) {} // No auth required
virtual void help( stringstream& help ) const {
lastError.disableForCommand(); // SERVER-11492
help << "return error status of the last operation on this connection\n"
<< "options:\n"
<< " { fsync:true } - fsync before returning, or wait for journal commit if running with --journal\n"
<< " { j:true } - wait for journal commit if running with --journal\n"
<< " { w:n } - await replication to n servers (including self) before returning\n"
<< " { w:'majority' } - await replication to majority of set\n"
<< " { wtimeout:m} - timeout for w in m milliseconds";
}
bool run(OperationContext* txn, const string& dbname,
BSONObj& cmdObj,
int,
string& errmsg,
BSONObjBuilder& result,
bool fromRepl ) {
//
// Correct behavior here is very finicky.
//
// 1. The first step is to append the error that occurred on the previous operation.
// This adds an "err" field to the command, which is *not* the command failing.
//
// 2. Next we parse and validate write concern options. If these options are invalid
// the command fails no matter what, even if we actually had an error earlier. The
// reason for checking here is to match legacy behavior on these kind of failures -
// we'll still get an "err" field for the write error.
//
// 3. If we had an error on the previous operation, we then return immediately.
//
// 4. Finally, we actually enforce the write concern. All errors *except* timeout are
// reported with ok : 0.0, to match legacy behavior.
//
// There is a special case when "wOpTime" and "wElectionId" are explicitly provided by
// the client (mongos) - in this case we *only* enforce the write concern if it is
// valid.
//
// We always need to either report "err" (if ok : 1) or "errmsg" (if ok : 0), even if
// err is null.
//
LastError *le = lastError.disableForCommand();
// Always append lastOp and connectionId
Client& c = cc();
c.appendLastOp( result );
// for sharding; also useful in general for debugging
result.appendNumber( "connectionId" , c.getConnectionId() );
OpTime lastOpTime;
BSONField wOpTimeField("wOpTime");
FieldParser::FieldState extracted = FieldParser::extract(cmdObj, wOpTimeField,
&lastOpTime, &errmsg);
if (!extracted) {
result.append("badGLE", cmdObj);
appendCommandStatus(result, false, errmsg);
return false;
}
bool lastOpTimePresent = extracted != FieldParser::FIELD_NONE;
if (!lastOpTimePresent) {
// Use the client opTime if no wOpTime is specified
lastOpTime = cc().getLastOp();
}
OID electionId;
BSONField wElectionIdField("wElectionId");
extracted = FieldParser::extract(cmdObj, wElectionIdField,
&electionId, &errmsg);
if (!extracted) {
result.append("badGLE", cmdObj);
appendCommandStatus(result, false, errmsg);
return false;
}
bool electionIdPresent = extracted != FieldParser::FIELD_NONE;
bool errorOccurred = false;
// Errors aren't reported when wOpTime is used
if ( !lastOpTimePresent ) {
if ( le->nPrev != 1 ) {
errorOccurred = LastError::noError.appendSelf( result, false );
le->appendSelfStatus( result );
}
else {
errorOccurred = le->appendSelf( result, false );
}
}
BSONObj writeConcernDoc = cmdObj;
// Use the default options if we have no gle options aside from wOpTime/wElectionId
const int nFields = cmdObj.nFields();
bool useDefaultGLEOptions = (nFields == 1) ||
(nFields == 2 && lastOpTimePresent) ||
(nFields == 3 && lastOpTimePresent && electionIdPresent);
if ( useDefaultGLEOptions && getLastErrorDefault ) {
writeConcernDoc = *getLastErrorDefault;
}
//
// Validate write concern no matter what, this matches 2.4 behavior
//
WriteConcernOptions writeConcern;
Status status = writeConcern.parse( writeConcernDoc );
if ( status.isOK() ) {
// Ensure options are valid for this host
status = validateWriteConcern( writeConcern );
}
if ( !status.isOK() ) {
result.append( "badGLE", writeConcernDoc );
return appendCommandStatus( result, status );
}
// Don't wait for replication if there was an error reported - this matches 2.4 behavior
if ( errorOccurred ) {
dassert( !lastOpTimePresent );
return true;
}
// No error occurred, so we won't duplicate these fields with write concern errors
dassert( result.asTempObj()["err"].eoo() );
dassert( result.asTempObj()["code"].eoo() );
// If we got an electionId, make sure it matches
if (electionIdPresent) {
if (!repl::theReplSet) {
// Ignore electionIds of 0 from mongos.
if (electionId != OID()) {
errmsg = "wElectionId passed but no replication active";
result.append("code", ErrorCodes::BadValue);
return false;
}
}
else {
if (electionId != repl::theReplSet->getElectionId()) {
LOG(3) << "oid passed in is " << electionId
<< ", but our id is " << repl::theReplSet->getElectionId();
errmsg = "election occurred after write";
result.append("code", ErrorCodes::WriteConcernFailed);
return false;
}
}
}
cc().curop()->setMessage( "waiting for write concern" );
WriteConcernResult wcResult;
status = waitForWriteConcern( txn, writeConcern, lastOpTime, &wcResult );
wcResult.appendTo( writeConcern, &result );
// For backward compatibility with 2.4, wtimeout returns ok : 1.0
if ( wcResult.wTimedOut ) {
dassert( !wcResult.err.empty() ); // so we always report err
dassert( !status.isOK() );
result.append( "errmsg", "timed out waiting for slaves" );
result.append( "code", status.code() );
return true;
}
return appendCommandStatus( result, status );
}
} cmdGetLastError;
class CmdGetPrevError : public Command {
public:
virtual bool isWriteCommandForConfigServer() const { return false; }
virtual void help( stringstream& help ) const {
help << "check for errors since last reseterror commandcal";
}
virtual bool slaveOk() const {
return true;
}
virtual void addRequiredPrivileges(const std::string& dbname,
const BSONObj& cmdObj,
std::vector* out) {} // No auth required
CmdGetPrevError() : Command("getPrevError", false, "getpreverror") {}
bool run(OperationContext* txn, const string& dbname, BSONObj& cmdObj, int, string& errmsg, BSONObjBuilder& result, bool fromRepl) {
LastError *le = lastError.disableForCommand();
le->appendSelf( result );
if ( le->valid )
result.append( "nPrev", le->nPrev );
else
result.append( "nPrev", -1 );
return true;
}
} cmdGetPrevError;
}