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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::kExecutor
#include "mongo/platform/basic.h"
#include <algorithm>
#include <memory>
#include <vector>
#include "mongo/client/remote_command_retry_scheduler.h"
#include "mongo/util/assert_util.h"
#include "mongo/util/destructor_guard.h"
#include "mongo/util/log.h"
namespace mongo {
RemoteCommandRetryScheduler::RemoteCommandRetryScheduler(
executor::TaskExecutor* executor,
const executor::RemoteCommandRequest& request,
const executor::TaskExecutor::RemoteCommandCallbackFn& callback,
std::unique_ptr<RetryPolicy> retryPolicy)
: _executor(executor),
_request(request),
_callback(callback),
_retryPolicy(std::move(retryPolicy)) {
uassert(ErrorCodes::BadValue, "task executor cannot be null", executor);
uassert(ErrorCodes::BadValue,
"source in remote command request cannot be empty",
!request.target.empty());
uassert(ErrorCodes::BadValue,
"database name in remote command request cannot be empty",
!request.dbname.empty());
uassert(ErrorCodes::BadValue,
"command object in remote command request cannot be empty",
!request.cmdObj.isEmpty());
uassert(ErrorCodes::BadValue, "remote command callback function cannot be null", callback);
uassert(ErrorCodes::BadValue, "retry policy cannot be null", _retryPolicy);
uassert(ErrorCodes::BadValue,
"policy max attempts cannot be zero",
_retryPolicy->getMaximumAttempts() != 0);
uassert(ErrorCodes::BadValue,
"policy max response elapsed total cannot be negative",
!(_retryPolicy->getMaximumResponseElapsedTotal() !=
executor::RemoteCommandRequest::kNoTimeout &&
_retryPolicy->getMaximumResponseElapsedTotal() < Milliseconds(0)));
}
RemoteCommandRetryScheduler::~RemoteCommandRetryScheduler() {
DESTRUCTOR_GUARD(shutdown(); join(););
}
bool RemoteCommandRetryScheduler::isActive() const {
stdx::lock_guard<stdx::mutex> lock(_mutex);
return _isActive_inlock();
}
bool RemoteCommandRetryScheduler::_isActive_inlock() const {
return State::kRunning == _state || State::kShuttingDown == _state;
}
Status RemoteCommandRetryScheduler::startup() {
stdx::lock_guard<stdx::mutex> lock(_mutex);
switch (_state) {
case State::kPreStart:
_state = State::kRunning;
break;
case State::kRunning:
return Status(ErrorCodes::IllegalOperation, "scheduler already started");
case State::kShuttingDown:
return Status(ErrorCodes::ShutdownInProgress, "scheduler shutting down");
case State::kComplete:
return Status(ErrorCodes::ShutdownInProgress, "scheduler completed");
}
auto scheduleStatus = _schedule_inlock();
if (!scheduleStatus.isOK()) {
_state = State::kComplete;
return scheduleStatus;
}
return Status::OK();
}
void RemoteCommandRetryScheduler::shutdown() {
executor::TaskExecutor::CallbackHandle remoteCommandCallbackHandle;
{
stdx::lock_guard<stdx::mutex> lock(_mutex);
switch (_state) {
case State::kPreStart:
// Transition directly from PreStart to Complete if not started yet.
_state = State::kComplete;
return;
case State::kRunning:
_state = State::kShuttingDown;
break;
case State::kShuttingDown:
case State::kComplete:
// Nothing to do if we are already in ShuttingDown or Complete state.
return;
}
remoteCommandCallbackHandle = _remoteCommandCallbackHandle;
}
invariant(remoteCommandCallbackHandle.isValid());
_executor->cancel(remoteCommandCallbackHandle);
}
void RemoteCommandRetryScheduler::join() {
stdx::unique_lock<stdx::mutex> lock(_mutex);
_condition.wait(lock, [this]() { return !_isActive_inlock(); });
}
std::string RemoteCommandRetryScheduler::toString() const {
stdx::lock_guard<stdx::mutex> lock(_mutex);
str::stream output;
output << "RemoteCommandRetryScheduler";
output << " request: " << _request.toString();
output << " active: " << _isActive_inlock();
if (_remoteCommandCallbackHandle.isValid()) {
output << " callbackHandle.valid: " << _remoteCommandCallbackHandle.isValid();
output << " callbackHandle.cancelled: " << _remoteCommandCallbackHandle.isCanceled();
}
output << " attempt: " << _currentAttempt;
output << " retryPolicy: " << _retryPolicy->toString();
return output;
}
Status RemoteCommandRetryScheduler::_schedule_inlock() {
++_currentAttempt;
auto scheduleResult = _executor->scheduleRemoteCommand(
_request, [this](const auto& x) { return this->_remoteCommandCallback(x); });
if (!scheduleResult.isOK()) {
return scheduleResult.getStatus();
}
_remoteCommandCallbackHandle = scheduleResult.getValue();
return Status::OK();
}
void RemoteCommandRetryScheduler::_remoteCommandCallback(
const executor::TaskExecutor::RemoteCommandCallbackArgs& rcba) {
const auto& status = rcba.response.status;
// Use a lambda to avoid unnecessary lock acquisition when checking conditions for termination.
auto getCurrentAttempt = [this]() {
stdx::lock_guard<stdx::mutex> lock(_mutex);
return _currentAttempt;
};
if (status.isOK() || status == ErrorCodes::CallbackCanceled ||
!_retryPolicy->shouldRetryOnError(status.code()) ||
getCurrentAttempt() == _retryPolicy->getMaximumAttempts()) {
_onComplete(rcba);
return;
}
// TODO(benety): Check cumulative elapsed time of failed responses received against retry
// policy. Requires SERVER-24067.
auto scheduleStatus = [this]() {
stdx::lock_guard<stdx::mutex> lock(_mutex);
if (State::kShuttingDown == _state) {
return Status(ErrorCodes::CallbackCanceled,
"scheduler was shut down before retrying command");
}
return _schedule_inlock();
}();
if (!scheduleStatus.isOK()) {
_onComplete({rcba.executor, rcba.myHandle, rcba.request, scheduleStatus});
return;
}
}
void RemoteCommandRetryScheduler::_onComplete(
const executor::TaskExecutor::RemoteCommandCallbackArgs& rcba) {
invariant(_callback);
_callback(rcba);
// This will release the resources held by the '_callback' function object. To avoid any issues
// with destruction logic in the function object's resources accessing this
// RemoteCommandRetryScheduler, we release this function object outside the lock.
_callback = {};
stdx::lock_guard<stdx::mutex> lock(_mutex);
invariant(_isActive_inlock());
_state = State::kComplete;
_condition.notify_all();
}
} // namespace mongo
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