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arangodb/arangod/StorageEngine/EngineSelectorFeature.cpp

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2.8 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2016 ArangoDB GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
////////////////////////////////////////////////////////////////////////////////
#include "EngineSelectorFeature.h"
#include "ApplicationFeatures/ApplicationServer.h"
#include "ProgramOptions/ProgramOptions.h"
#include "ProgramOptions/Section.h"
#include "StorageEngine/MMFilesEngine.h"
#include "StorageEngine/RocksDBEngine.h"
#include "StorageEngine/StorageEngine.h"
using namespace arangodb;
using namespace arangodb::options;
StorageEngine* EngineSelectorFeature::ENGINE = nullptr;
EngineSelectorFeature::EngineSelectorFeature(
application_features::ApplicationServer* server)
: ApplicationFeature(server, "EngineSelector"), _engine(MMFilesEngine::EngineName) {
setOptional(false);
requiresElevatedPrivileges(false);
startsAfter("Logger");
}
void EngineSelectorFeature::collectOptions(std::shared_ptr<ProgramOptions> options) {
options->addSection("server", "Server features");
options->addHiddenOption("--server.storage-engine",
"storage engine type",
new DiscreteValuesParameter<StringParameter>(&_engine, availableEngines()));
}
void EngineSelectorFeature::prepare() {
// deactivate all engines but the selected one
for (auto& engine : availableEngines()) {
StorageEngine* e = application_features::ApplicationServer::getFeature<StorageEngine>(engine);
if (engine == _engine) {
// this is the selected engine
LOG_TOPIC(TRACE, Logger::STARTUP) << "using storage engine " << engine;
e->enable();
// register storage engine
ENGINE = e;
} else {
// turn off all other storage engines
LOG_TOPIC(TRACE, Logger::STARTUP) << "disabling storage engine " << engine;
e->disable();
}
}
TRI_ASSERT(ENGINE != nullptr);
}
void EngineSelectorFeature::unprepare() {
// unregister storage engine
ENGINE = nullptr;
}
// return all available storage engines
std::unordered_set<std::string> EngineSelectorFeature::availableEngines() {
return std::unordered_set<std::string>{
MMFilesEngine::EngineName, RocksDBEngine::EngineName
};
}