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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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 "mongo/db/commands.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/s/cluster_commands_helpers.h"
#include "mongo/s/grid.h"
#include "mongo/util/log.h"
namespace mongo {
namespace {
class FileMD5Cmd : public BasicCommand {
public:
FileMD5Cmd() : BasicCommand("filemd5") {}
std::string help() const override {
return " example: { filemd5 : ObjectId(aaaaaaa) , root : \"fs\" }";
}
AllowedOnSecondary secondaryAllowed(ServiceContext*) const override {
return AllowedOnSecondary::kAlways;
}
bool adminOnly() const override {
return false;
}
std::string parseNs(const std::string& dbname, const BSONObj& cmdObj) const override {
std::string collectionName;
if (const auto rootElt = cmdObj["root"]) {
uassert(ErrorCodes::InvalidNamespace,
"'root' must be of type String",
rootElt.type() == BSONType::String);
collectionName = rootElt.str();
}
if (collectionName.empty())
collectionName = "fs";
collectionName += ".chunks";
return NamespaceString(dbname, collectionName).ns();
}
void addRequiredPrivileges(const std::string& dbname,
const BSONObj& cmdObj,
std::vector<Privilege>* out) const override {
out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), ActionType::find));
}
bool supportsWriteConcern(const BSONObj& cmd) const override {
return false;
}
bool run(OperationContext* opCtx,
const std::string& dbName,
const BSONObj& cmdObj,
BSONObjBuilder& result) override {
const NamespaceString nss(parseNs(dbName, cmdObj));
const auto routingInfo =
uassertStatusOK(Grid::get(opCtx)->catalogCache()->getCollectionRoutingInfo(opCtx, nss));
const auto callShardFn = [opCtx, &nss, &routingInfo](const BSONObj& cmdObj,
const BSONObj& routingQuery) {
auto shardResults =
scatterGatherVersionedTargetByRoutingTable(opCtx,
nss.db(),
nss,
routingInfo,
cmdObj,
ReadPreferenceSetting::get(opCtx),
Shard::RetryPolicy::kIdempotent,
routingQuery,
CollationSpec::kSimpleSpec);
invariant(shardResults.size() == 1);
const auto shardResponse = uassertStatusOK(std::move(shardResults[0].swResponse));
uassertStatusOK(shardResponse.status);
const auto& res = shardResponse.data;
uassertStatusOK(getStatusFromCommandResult(res));
return res;
};
// If the collection is not sharded, or is sharded only on the 'files_id' field, we only
// need to target a single shard, because the files' chunks can only be contained in a
// single sharded chunk
if (!routingInfo.cm() ||
SimpleBSONObjComparator::kInstance.evaluate(
routingInfo.cm()->getShardKeyPattern().toBSON() == BSON("files_id" << 1))) {
CommandHelpers::filterCommandReplyForPassthrough(
callShardFn(CommandHelpers::filterCommandRequestForPassthrough(cmdObj),
BSON("files_id" << cmdObj.firstElement())),
&result);
return true;
}
// Since the filemd5 command is tailored specifically for GridFS, there is no need to
// support arbitrary shard keys
uassert(ErrorCodes::IllegalOperation,
"The GridFS fs.chunks collection must be sharded on either {files_id:1} or "
"{files_id:1, n:1}",
SimpleBSONObjComparator::kInstance.evaluate(
routingInfo.cm()->getShardKeyPattern().toBSON() ==
BSON("files_id" << 1 << "n" << 1)));
// Theory of operation:
//
// Starting with n=0, send filemd5 command to shard with that chunk (gridfs chunk not
// sharding chunk). That shard will then compute a partial md5 state (passed in the
// "md5state" field) for all contiguous chunks that it contains. When it runs out or hits a
// discontinuity (eg [1,2,7]) it returns what it has done so far. This is repeated as long
// as we keep getting more chunks. The end condition is when we go to look for chunk n and
// it doesn't exist. This means that the file's last chunk is n-1, so we return the computed
// md5 results.
int numGridFSChunksProcessed = 0;
BSONObj lastResult;
while (true) {
const auto res = callShardFn(
[&] {
BSONObjBuilder bb(CommandHelpers::filterCommandRequestForPassthrough(cmdObj));
bb.append("partialOk", true);
bb.append("startAt", numGridFSChunksProcessed);
if (!lastResult.isEmpty()) {
bb.append(lastResult["md5state"]);
}
return bb.obj();
}(),
BSON("files_id" << cmdObj.firstElement() << "n" << numGridFSChunksProcessed));
uassert(16246,
str::stream() << "Shard for database " << nss.db()
<< " is too old to support GridFS sharded by {files_id:1, n:1}",
res.hasField("md5state"));
lastResult = res;
const int numChunks = res["numChunks"].numberInt();
if (numGridFSChunksProcessed == numChunks) {
// No new data means we've reached the end of the file
CommandHelpers::filterCommandReplyForPassthrough(res, &result);
return true;
}
uassert(ErrorCodes::InternalError,
str::stream() << "Command returned numChunks of " << numChunks
<< " which is less than the number of chunks processes so far "
<< numGridFSChunksProcessed,
numChunks > numGridFSChunksProcessed);
numGridFSChunksProcessed = numChunks;
}
MONGO_UNREACHABLE;
}
} fileMD5Cmd;
} // namespace
} // namespace mongo
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