1
0
Fork 0
arangodb/lib/ApplicationFeatures/ApplicationFeature.cpp

112 lines
4.0 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 "ApplicationFeature.h"
#include "ApplicationFeatures/ApplicationServer.h"
#include "Basics/Logger.h"
using namespace arangodb::application_features;
using namespace arangodb::options;
ApplicationFeature::ApplicationFeature(ApplicationServer* server,
std::string const& name)
: _server(server),
_name(name),
_enabled(true),
_optional(false),
_requiresElevatedPrivileges(false) {}
ApplicationFeature::~ApplicationFeature() {}
// add the feature's options to the global list of options. this method will be
// called regardless of whether to feature is enabled or disabled
void ApplicationFeature::collectOptions(std::shared_ptr<ProgramOptions>) {
LOG(TRACE) << name() << "::collectOptions";
}
// validate the feature's options. this method will only be called for active
// features, after the ApplicationServer has determined which features should be
// turned off globally. in order to abort further processing in case of invalid
// parameter values, the feature should bail out by calling
// `abortInvalidParameters()`
void ApplicationFeature::validateOptions(std::shared_ptr<ProgramOptions>) {
LOG(TRACE) << name() << "::validateOptions";
}
// preparation phase for feature
// in the preparation phase, the features must not start any threads
// furthermore, they must not write any files under elevated privileges
// if they want other features to access them, or if they want to access
// these files with dropped privileges
void ApplicationFeature::prepare() { LOG(TRACE) << name() << "::prepare"; }
// start the feature
void ApplicationFeature::start() { LOG(TRACE) << name() << "::start"; }
// notify the feature about a shutdown request
void ApplicationFeature::beginShutdown() {
LOG(TRACE) << name() << "::beginShutdown";
}
// stop and shut down the feature
void ApplicationFeature::stop() { LOG(TRACE) << name() << "::stop"; }
// determine all direct and indirect ancestors of a feature
std::unordered_set<std::string> ApplicationFeature::ancestors() const {
std::function<void(std::unordered_set<std::string>&, std::string const&)>
build = [this, &build](std::unordered_set<std::string>& found,
std::string const& name) {
for (auto& ancestor : this->server()->feature(name)->startsAfter()) {
found.emplace(ancestor);
build(found, ancestor);
}
};
std::unordered_set<std::string> found;
build(found, name());
if (found.find(name()) != found.end()) {
THROW_ARANGO_EXCEPTION_MESSAGE(
TRI_ERROR_INTERNAL,
"dependencies for feature '" + name() + "' are cyclic");
}
return found;
}
// whether the feature starts before another
bool ApplicationFeature::doesStartBefore(std::string const& other) const {
auto otherAncestors = _server->feature(other)->ancestors();
if (otherAncestors.find(name()) != otherAncestors.end()) {
// we are an ancestor of the other feature
return true;
}
auto ourAncestors = ancestors();
if (ourAncestors.find(other) != ourAncestors.end()) {
// the other feature is an ancestor of us
return false;
}
// no direct or indirect relationship between features
return false;
}