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arangodb/lib/ApplicationFeatures/ApplicationServer.h

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////////////////////////////////////////////////////////////////////////////////
/// 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
////////////////////////////////////////////////////////////////////////////////
#ifndef APPLICATION_FEATURES_APPLICATION_SERVER_H
#define APPLICATION_FEATURES_APPLICATION_SERVER_H 1
#include "Basics/Common.h"
namespace arangodb {
namespace options {
class ProgramOptions;
}
namespace application_features {
class ApplicationFeature;
class ApplicationServer {
ApplicationServer(ApplicationServer const&) = delete;
ApplicationServer& operator=(ApplicationServer const&) = delete;
public:
explicit ApplicationServer(std::shared_ptr<options::ProgramOptions>);
~ApplicationServer();
// adds a feature to the application server. the application server
// will take ownership of the feature object and destroy it in its
// destructor
void addFeature(ApplicationFeature*);
// checks for the existence of a named feature. will not throw when used for
// a non-existing feature
bool exists(std::string const&) const;
// returns a pointer to a named feature. will throw when used for
// a non-existing feature
ApplicationFeature* feature(std::string const&) const;
// return whether or not a feature is enabled
// will throw when called for a non-existing feature
bool isEnabled(std::string const&) const;
// return whether or not a feature is optional
// will throw when called for a non-existing feature
bool isOptional(std::string const&) const;
// return whether or not a feature is required
// will throw when called for a non-existing feature
bool isRequired(std::string const&) const;
// this method will initialize and validate options
// of all feature, start them and wait for a shutdown
// signal. after that, it will shutdown all features
void run();
// signal the server to shut down
void beginShutdown();
private:
// fail and abort with the specified message
void fail(std::string const& message);
// walks over all features and runs a callback function for them
void apply(std::function<void(ApplicationFeature*)>, bool enabledOnly);
// collects the program options from all features,
// without validating them
void collectOptions();
// allows features to cross-validate their program options
void validateOptions();
// enable automatic features
void enableAutomaticFeatures();
// setup and validate all feature dependencies, determine feature order
void setupDependencies();
// allows features to prepare themselves
void prepare();
// starts features
void start();
// stops features
void stop();
// after start, the server will wait in this method until
// beginShutdown is called
void wait();
void raisePrivilegesTemporarily();
void dropPrivilegesTemporarily();
void dropPrivilegesPermanently();
private:
// the shared program options
std::shared_ptr<options::ProgramOptions> _options;
// map of feature names to features
std::unordered_map<std::string, ApplicationFeature*> _features;
// features order for prepare/start
std::vector<ApplicationFeature*> _orderedFeatures;
// stop flag. this is being changed by calling beginShutdown
std::atomic<bool> _stopping;
// whether or not privileges have been dropped permanently
bool _privilegesDropped;
};
}
}
#endif