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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::kReplication
#include "mongo/platform/basic.h"
#include "mongo/db/repl/task_runner.h"
#include <memory>
#include "mongo/db/auth/authorization_manager_global.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/client.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/service_context.h"
#include "mongo/util/assert_util.h"
#include "mongo/util/concurrency/old_thread_pool.h"
#include "mongo/util/concurrency/thread_name.h"
#include "mongo/util/mongoutils/str.h"
#include "mongo/util/log.h"
namespace mongo {
namespace repl {
namespace {
/**
* Runs a single task runner task.
* Any exceptions thrown by the task will be logged and converted into a
* next action of kCancel.
*/
TaskRunner::NextAction runSingleTask(const TaskRunner::Task& task,
OperationContext* txn,
const Status& status) {
try {
return task(txn, status);
} catch (...) {
log() << "Unhandled exception in task runner: " << exceptionToStatus();
}
return TaskRunner::NextAction::kCancel;
}
} // namespace
// static
TaskRunner::Task TaskRunner::makeCancelTask() {
return [](OperationContext* txn, const Status& status) { return NextAction::kCancel; };
}
TaskRunner::TaskRunner(OldThreadPool* threadPool)
: _threadPool(threadPool), _active(false), _cancelRequested(false) {
uassert(ErrorCodes::BadValue, "null thread pool", threadPool);
}
TaskRunner::~TaskRunner() {
DESTRUCTOR_GUARD(stdx::unique_lock<stdx::mutex> lk(_mutex);
if (!_active) { return; } _cancelRequested = true;
_condition.notify_all();
while (_active) { _condition.wait(lk); });
}
std::string TaskRunner::getDiagnosticString() const {
stdx::lock_guard<stdx::mutex> lk(_mutex);
str::stream output;
output << "TaskRunner";
output << " scheduled tasks: " << _tasks.size();
output << " active: " << _active;
output << " cancel requested: " << _cancelRequested;
return output;
}
bool TaskRunner::isActive() const {
stdx::lock_guard<stdx::mutex> lk(_mutex);
return _active;
}
void TaskRunner::schedule(const Task& task) {
invariant(task);
stdx::lock_guard<stdx::mutex> lk(_mutex);
_tasks.push_back(task);
_condition.notify_all();
if (_active) {
return;
}
_threadPool->schedule(stdx::bind(&TaskRunner::_runTasks, this));
_active = true;
_cancelRequested = false;
}
void TaskRunner::cancel() {
stdx::lock_guard<stdx::mutex> lk(_mutex);
_cancelRequested = true;
_condition.notify_all();
}
void TaskRunner::_runTasks() {
Client* client = nullptr;
ServiceContext::UniqueOperationContext txn;
while (Task task = _waitForNextTask()) {
if (!txn) {
if (!client) {
// We initialize cc() because ServiceContextMongoD::_newOpCtx() expects cc()
// to be equal to the client used to create the operation context.
Client::initThreadIfNotAlready();
client = &cc();
if (getGlobalAuthorizationManager()->isAuthEnabled()) {
AuthorizationSession::get(client)->grantInternalAuthorization();
}
}
txn = client->makeOperationContext();
}
NextAction nextAction = runSingleTask(task, txn.get(), Status::OK());
if (nextAction != NextAction::kKeepOperationContext) {
txn.reset();
}
if (nextAction == NextAction::kCancel) {
break;
}
// Release thread back to pool after disposing if no scheduled tasks in queue.
if (nextAction == NextAction::kDisposeOperationContext ||
nextAction == NextAction::kInvalid) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
if (_tasks.empty()) {
_finishRunTasks_inlock();
return;
}
}
}
txn.reset();
std::list<Task> tasks;
{
stdx::lock_guard<stdx::mutex> lk(_mutex);
tasks.swap(_tasks);
}
// Cancel remaining tasks with a CallbackCanceled status.
for (auto task : tasks) {
runSingleTask(task,
nullptr,
Status(ErrorCodes::CallbackCanceled,
"this task has been canceled by a previously invoked task"));
}
stdx::lock_guard<stdx::mutex> lk(_mutex);
_finishRunTasks_inlock();
}
void TaskRunner::_finishRunTasks_inlock() {
_active = false;
_cancelRequested = false;
_condition.notify_all();
}
TaskRunner::Task TaskRunner::_waitForNextTask() {
stdx::unique_lock<stdx::mutex> lk(_mutex);
while (_tasks.empty() && !_cancelRequested) {
_condition.wait(lk);
}
if (_cancelRequested) {
return Task();
}
Task task = _tasks.front();
_tasks.pop_front();
return task;
}
} // namespace repl
} // namespace mongo
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