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/**
* Copyright (C) 2015 MongoDB 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/>.
*
* 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kCommand
#include "mongo/platform/basic.h"
#include <set>
#include "mongo/client/connpool.h"
#include "mongo/db/auth/action_set.h"
#include "mongo/db/auth/action_type.h"
#include "mongo/db/auth/authorization_manager.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/catalog/document_validation.h"
#include "mongo/db/client.h"
#include "mongo/db/client.h"
#include "mongo/db/commands.h"
#include "mongo/db/operation_context.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/s/catalog/sharding_catalog_client.h"
#include "mongo/s/catalog/type_database.h"
#include "mongo/s/catalog_cache.h"
#include "mongo/s/client/shard_registry.h"
#include "mongo/s/commands/cluster_commands_common.h"
#include "mongo/s/commands/sharded_command_processing.h"
#include "mongo/s/config.h"
#include "mongo/s/grid.h"
#include "mongo/util/log.h"
namespace mongo {
using std::shared_ptr;
using std::set;
using std::string;
namespace {
class MoveDatabasePrimaryCommand : public Command {
public:
MoveDatabasePrimaryCommand() : Command("movePrimary", false, "moveprimary") {}
virtual bool slaveOk() const {
return true;
}
virtual bool adminOnly() const {
return true;
}
virtual bool supportsWriteConcern(const BSONObj& cmd) const override {
return true;
}
virtual void help(std::stringstream& help) const {
help << " example: { moveprimary : 'foo' , to : 'localhost:9999' }";
}
virtual Status checkAuthForCommand(Client* client,
const std::string& dbname,
const BSONObj& cmdObj) {
if (!AuthorizationSession::get(client)->isAuthorizedForActionsOnResource(
ResourcePattern::forDatabaseName(parseNs(dbname, cmdObj)), ActionType::moveChunk)) {
return Status(ErrorCodes::Unauthorized, "Unauthorized");
}
return Status::OK();
}
virtual std::string parseNs(const std::string& dbname, const BSONObj& cmdObj) const {
const auto nsElt = cmdObj.firstElement();
uassert(ErrorCodes::InvalidNamespace,
"'movePrimary' must be of type String",
nsElt.type() == BSONType::String);
return nsElt.str();
}
virtual bool run(OperationContext* txn,
const std::string& dbname_unused,
BSONObj& cmdObj,
int options,
std::string& errmsg,
BSONObjBuilder& result) {
const string dbname = parseNs("", cmdObj);
uassert(
ErrorCodes::InvalidNamespace,
str::stream() << "invalid db name specified: " << dbname,
NamespaceString::validDBName(dbname, NamespaceString::DollarInDbNameBehavior::Allow));
if (dbname == NamespaceString::kAdminDb || dbname == NamespaceString::kConfigDb ||
dbname == NamespaceString::kLocalDb) {
errmsg = "can't move primary for " + dbname + " database";
return false;
}
auto const catalogClient = Grid::get(txn)->catalogClient(txn);
auto const catalogCache = Grid::get(txn)->catalogCache();
auto const shardRegistry = Grid::get(txn)->shardRegistry();
// Flush all cached information. This can't be perfect, but it's better than nothing.
catalogCache->invalidate(dbname);
auto config = uassertStatusOK(catalogCache->getDatabase(txn, dbname));
const auto toElt = cmdObj["to"];
uassert(ErrorCodes::TypeMismatch,
"'to' must be of type String",
toElt.type() == BSONType::String);
const std::string to = toElt.str();
if (!to.size()) {
errmsg = "you have to specify where you want to move it";
return false;
}
const auto fromShard =
uassertStatusOK(shardRegistry->getShard(txn, config->getPrimaryId()));
const auto toShard = [&]() {
auto toShardStatus = shardRegistry->getShard(txn, to);
if (!toShardStatus.isOK()) {
const std::string msg(
str::stream() << "Could not move database '" << dbname << "' to shard '" << to
<< "' due to "
<< toShardStatus.getStatus().reason());
log() << msg;
uasserted(toShardStatus.getStatus().code(), msg);
}
return toShardStatus.getValue();
}();
uassert(ErrorCodes::IllegalOperation,
"it is already the primary",
fromShard->getId() != toShard->getId());
log() << "Moving " << dbname << " primary from: " << fromShard->toString()
<< " to: " << toShard->toString();
const std::string whyMessage(str::stream() << "Moving primary shard of " << dbname);
auto scopedDistLock = uassertStatusOK(catalogClient->getDistLockManager()->lock(
txn, dbname + "-movePrimary", whyMessage, DistLockManager::kDefaultLockTimeout));
const auto shardedColls = getAllShardedCollectionsForDb(txn, dbname);
// Record start in changelog
catalogClient->logChange(
txn,
"movePrimary.start",
dbname,
_buildMoveLogEntry(dbname, fromShard->toString(), toShard->toString(), shardedColls),
ShardingCatalogClient::kMajorityWriteConcern);
ScopedDbConnection toconn(toShard->getConnString());
// TODO ERH - we need a clone command which replays operations from clone start to now
// can just use local.oplog.$main
BSONObj cloneRes;
bool hasWCError = false;
{
BSONArrayBuilder barr;
for (const auto& shardedColl : shardedColls) {
barr.append(shardedColl.ns());
}
const bool worked = toconn->runCommand(
dbname,
BSON("clone" << fromShard->getConnString().toString() << "collsToIgnore"
<< barr.arr()
<< bypassDocumentValidationCommandOption()
<< true
<< "writeConcern"
<< txn->getWriteConcern().toBSON()),
cloneRes);
toconn.done();
if (!worked) {
log() << "clone failed" << redact(cloneRes);
errmsg = "clone failed";
return false;
}
if (auto wcErrorElem = cloneRes["writeConcernError"]) {
appendWriteConcernErrorToCmdResponse(toShard->getId(), wcErrorElem, result);
hasWCError = true;
}
}
// Update the new primary in the config server metadata
{
auto dbt = uassertStatusOK(catalogClient->getDatabase(txn, dbname)).value;
dbt.setPrimary(toShard->getId());
uassertStatusOK(catalogClient->updateDatabase(txn, dbname, dbt));
}
// Ensure the next attempt to retrieve the database or any of its collections will do a full
// reload
catalogCache->invalidate(dbname);
const string oldPrimary = fromShard->getConnString().toString();
ScopedDbConnection fromconn(fromShard->getConnString());
if (shardedColls.empty()) {
// TODO: Collections can be created in the meantime, and we should handle in the future.
log() << "movePrimary dropping database on " << oldPrimary
<< ", no sharded collections in " << dbname;
try {
BSONObj dropDBInfo;
fromconn->dropDatabase(dbname.c_str(), txn->getWriteConcern(), &dropDBInfo);
if (!hasWCError) {
if (auto wcErrorElem = dropDBInfo["writeConcernError"]) {
appendWriteConcernErrorToCmdResponse(
fromShard->getId(), wcErrorElem, result);
hasWCError = true;
}
}
} catch (DBException& e) {
e.addContext(str::stream() << "movePrimary could not drop the database " << dbname
<< " on "
<< oldPrimary);
throw;
}
} else if (cloneRes["clonedColls"].type() != Array) {
// Legacy behavior from old mongod with sharded collections, *do not* delete
// database, but inform user they can drop manually (or ignore).
warning() << "movePrimary legacy mongod behavior detected. "
<< "User must manually remove unsharded collections in database " << dbname
<< " on " << oldPrimary;
} else {
// We moved some unsharded collections, but not all
BSONObjIterator it(cloneRes["clonedColls"].Obj());
while (it.more()) {
BSONElement el = it.next();
if (el.type() == String) {
try {
log() << "movePrimary dropping cloned collection " << el.String() << " on "
<< oldPrimary;
BSONObj dropCollInfo;
fromconn->dropCollection(
el.String(), txn->getWriteConcern(), &dropCollInfo);
if (!hasWCError) {
if (auto wcErrorElem = dropCollInfo["writeConcernError"]) {
appendWriteConcernErrorToCmdResponse(
fromShard->getId(), wcErrorElem, result);
hasWCError = true;
}
}
} catch (DBException& e) {
e.addContext(str::stream()
<< "movePrimary could not drop the cloned collection "
<< el.String()
<< " on "
<< oldPrimary);
throw;
}
}
}
}
fromconn.done();
result << "primary" << toShard->toString();
// Record finish in changelog
catalogClient->logChange(
txn,
"movePrimary",
dbname,
_buildMoveLogEntry(dbname, oldPrimary, toShard->toString(), shardedColls),
ShardingCatalogClient::kMajorityWriteConcern);
return true;
}
private:
static BSONObj _buildMoveLogEntry(const std::string& db,
const std::string& from,
const std::string& to,
const std::vector<NamespaceString>& shardedColls) {
BSONObjBuilder details;
details.append("database", db);
details.append("from", from);
details.append("to", to);
BSONArrayBuilder collB(details.subarrayStart("shardedCollections"));
for (const auto& shardedColl : shardedColls) {
collB.append(shardedColl.ns());
}
collB.done();
return details.obj();
}
} clusterMovePrimaryCmd;
} // namespace
} // namespace mongo
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