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arangodb/arangod/Cluster/AgencyCallback.cpp

113 lines
3.4 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS 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 Andreas Streichardt
////////////////////////////////////////////////////////////////////////////////
#include "AgencyCallback.h"
#include <velocypack/Exception.h>
#include <velocypack/Parser.h>
#include <velocypack/velocypack-aliases.h>
#include <chrono>
#include <thread>
#include "Basics/MutexLocker.h"
using namespace arangodb;
AgencyCallback::AgencyCallback(AgencyComm& agency,
std::string const& key,
std::function<bool(VPackSlice const&)> const& cb,
bool needsValue)
: key(key),
_agency(agency),
_cb(cb),
_needsValue(needsValue) {
if (_needsValue) {
refetchAndUpdate();
}
}
void AgencyCallback::refetchAndUpdate() {
if (!_needsValue) {
// no need to pass any value to the callback
executeEmpty();
return;
}
AgencyCommResult result = _agency.getValues(key, true);
if (!result.successful()) {
return;
}
if (!result.parse("", false)) {
LOG(ERR) << "Cannot parse body " << result.body();
return;
}
std::map<std::string, AgencyCommResultEntry>::const_iterator it =
result._values.begin();
if (it == result._values.end()) {
std::shared_ptr<VPackBuilder> newData = std::make_shared<VPackBuilder>();
newData->add(VPackSlice::noneSlice());
checkValue(newData);
} else {
checkValue(it->second._vpack);
}
}
void AgencyCallback::checkValue(std::shared_ptr<VPackBuilder> newData) {
if (!_lastData || !_lastData->slice().equals(newData->slice())) {
LOG(DEBUG) << "Got new value " << newData->slice().typeName();
LOG(DEBUG) << "Got new value " << newData->toJson();
if (execute(newData)) {
_lastData = newData;
} else {
LOG(DEBUG) << "Callback was not successful for " << newData->toJson();
}
}
}
bool AgencyCallback::executeEmpty() {
LOG(DEBUG) << "Executing (empty)";
MUTEX_LOCKER(locker, _lock);
return _cb(VPackSlice::noneSlice());
}
bool AgencyCallback::execute(std::shared_ptr<VPackBuilder> newData) {
LOG(DEBUG) << "Executing";
MUTEX_LOCKER(locker, _lock);
return _cb(newData->slice());
}
void AgencyCallback::waitWithFailover(double timeout) {
// mop: todo thread safe? check with max
std::shared_ptr<VPackBuilder> beginData = _lastData;
std::this_thread::sleep_for(std::chrono::milliseconds(static_cast<int>(timeout * 1000)));
if (!_lastData || _lastData->slice().equals(beginData->slice())) {
LOG(DEBUG) << "Waiting done and nothing happended. Refetching to be sure";
// mop: watches have not triggered during our sleep...recheck to be sure
refetchAndUpdate();
}
}