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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.
*/
#include "mongo/platform/basic.h"
#include "mongo/client/remote_command_runner_impl.h"
#include "mongo/base/status_with.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/query/cursor_response.h"
#include "mongo/db/query/getmore_request.h"
#include "mongo/executor/downconvert_find_and_getmore_commands.h"
#include "mongo/executor/network_connection_hook.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/rpc/protocol.h"
#include "mongo/util/assert_util.h"
namespace mongo {
namespace {
using executor::RemoteCommandRequest;
using executor::RemoteCommandResponse;
/**
* Calculates the timeout for a network operation expiring at "expDate", given
* that it is now "nowDate".
*
* Returns 0ms to indicate no expiration date, a number of milliseconds until "expDate", or
* ErrorCodes::ExceededTimeLimit if "expDate" is not later than "nowDate".
*/
StatusWith<Milliseconds> getTimeoutMillis(const Date_t expDate, const Date_t nowDate) {
if (expDate == RemoteCommandRequest::kNoExpirationDate) {
return Milliseconds(0);
}
if (expDate <= nowDate) {
return {ErrorCodes::ExceededTimeLimit,
str::stream() << "Went to run command, but it was too late. "
"Expiration was set to "
<< dateToISOStringUTC(expDate)};
}
return expDate - nowDate;
}
/**
* Peeks at error in cursor. If an error has occurred, converts the {$err: "...", code: N}
* cursor error to a Status.
*/
Status getStatusFromCursorResult(DBClientCursor& cursor) {
BSONObj error;
if (!cursor.peekError(&error)) {
return Status::OK();
}
BSONElement e = error.getField("code");
return Status(e.isNumber() ? ErrorCodes::fromInt(e.numberInt()) : ErrorCodes::UnknownError,
getErrField(error).valuestrsafe());
}
using RequestDownconverter = StatusWith<Message> (*)(const RemoteCommandRequest&);
using ReplyUpconverter = StatusWith<RemoteCommandResponse> (*)(std::int32_t requestId,
StringData cursorNamespace,
const Message& response);
template <RequestDownconverter downconvertRequest, ReplyUpconverter upconvertReply>
StatusWith<RemoteCommandResponse> runDownconvertedCommand(DBClientConnection* conn,
const RemoteCommandRequest& request) {
auto swDownconvertedRequest = downconvertRequest(request);
if (!swDownconvertedRequest.isOK()) {
return swDownconvertedRequest.getStatus();
}
Message requestMsg{std::move(swDownconvertedRequest.getValue())};
Message responseMsg;
try {
conn->call(requestMsg, responseMsg, true, nullptr);
} catch (...) {
return exceptionToStatus();
}
auto messageId = requestMsg.header().getId();
return upconvertReply(messageId, DbMessage(requestMsg).getns(), responseMsg);
}
/**
* Downconverts the specified find command to a find protocol operation and sends it to the
* server on the specified connection.
*/
StatusWith<RemoteCommandResponse> runDownconvertedFindCommand(DBClientConnection* conn,
const RemoteCommandRequest& request) {
return runDownconvertedCommand<executor::downconvertFindCommandRequest,
executor::upconvertLegacyQueryResponse>(conn, request);
}
/**
* Downconverts the specified getMore command to legacy getMore operation and sends it to the
* server on the specified connection.
*/
StatusWith<RemoteCommandResponse> runDownconvertedGetMoreCommand(
DBClientConnection* conn, const RemoteCommandRequest& request) {
return runDownconvertedCommand<executor::downconvertGetMoreCommandRequest,
executor::upconvertLegacyGetMoreResponse>(conn, request);
}
} // namespace
RemoteCommandRunnerImpl::RemoteCommandRunnerImpl(
int messagingTags, std::unique_ptr<executor::NetworkConnectionHook> hook)
: _connPool(messagingTags, std::move(hook)) {}
RemoteCommandRunnerImpl::~RemoteCommandRunnerImpl() {
invariant(!_active);
}
void RemoteCommandRunnerImpl::startup() {
_active = true;
}
void RemoteCommandRunnerImpl::shutdown() {
if (!_active) {
return;
}
_connPool.closeAllInUseConnections();
_active = false;
}
StatusWith<RemoteCommandResponse> RemoteCommandRunnerImpl::runCommand(
const RemoteCommandRequest& request) {
try {
const Date_t requestStartDate = Date_t::now();
const auto timeoutMillis = getTimeoutMillis(request.expirationDate, requestStartDate);
if (!timeoutMillis.isOK()) {
return StatusWith<RemoteCommandResponse>(timeoutMillis.getStatus());
}
ConnectionPool::ConnectionPtr conn(
&_connPool, request.target, requestStartDate, timeoutMillis.getValue());
BSONObj output;
BSONObj metadata;
// If remote server does not support either find or getMore commands, down convert
// to using DBClientInterface::query()/getMore().
// Perform down conversion based on wire protocol version.
// 'commandName' will be an empty string if the command object is an empty BSON
// document.
StringData commandName = request.cmdObj.firstElement().fieldNameStringData();
const auto isFindCmd = commandName == LiteParsedQuery::kFindCommandName;
const auto isGetMoreCmd = commandName == GetMoreRequest::kGetMoreCommandName;
const auto isFindOrGetMoreCmd = isFindCmd || isGetMoreCmd;
// We are using the wire version to check if we need to downconverting find/getMore
// requests because coincidentally, the find/getMore command is only supported by
// servers that also accept OP_COMMAND.
bool supportsFindAndGetMoreCommands = rpc::supportsWireVersionForOpCommandInMongod(
conn.get()->getMinWireVersion(), conn.get()->getMaxWireVersion());
if (!isFindOrGetMoreCmd || supportsFindAndGetMoreCommands) {
rpc::UniqueReply commandResponse =
conn.get()->runCommandWithMetadata(request.dbname,
request.cmdObj.firstElementFieldName(),
request.metadata,
request.cmdObj);
output = commandResponse->getCommandReply().getOwned();
metadata = commandResponse->getMetadata().getOwned();
} else if (isFindCmd) {
return runDownconvertedFindCommand(conn.get(), request);
} else if (isGetMoreCmd) {
return runDownconvertedGetMoreCommand(conn.get(), request);
}
const Date_t requestFinishDate = Date_t::now();
conn.done(requestFinishDate);
return StatusWith<RemoteCommandResponse>(
RemoteCommandResponse(std::move(output),
std::move(metadata),
Milliseconds(requestFinishDate - requestStartDate)));
} catch (const DBException& ex) {
return StatusWith<RemoteCommandResponse>(ex.toStatus());
} catch (const std::exception& ex) {
return StatusWith<RemoteCommandResponse>(
ErrorCodes::UnknownError,
str::stream() << "Sending command " << request.cmdObj << " on database "
<< request.dbname
<< " over network to "
<< request.target.toString()
<< " received exception "
<< ex.what());
}
}
} // namespace mongo
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