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arangodb/arangod/Agency/State.cpp

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8.9 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 Kaveh Vahedipour
////////////////////////////////////////////////////////////////////////////////
#include "State.h"
#include <velocypack/Buffer.h>
#include <velocypack/Slice.h>
#include <velocypack/velocypack-aliases.h>
#include <chrono>
#include <iomanip>
#include <sstream>
#include <thread>
#include "Aql/Query.h"
#include "Basics/VelocyPackHelper.h"
#include "RestServer/QueryRegistryFeature.h"
#include "Utils/OperationOptions.h"
#include "Utils/OperationResult.h"
#include "Utils/SingleCollectionTransaction.h"
#include "Utils/StandaloneTransactionContext.h"
#include "VocBase/collection.h"
#include "VocBase/vocbase.h"
using namespace arangodb;
using namespace arangodb::application_features;
using namespace arangodb::consensus;
using namespace arangodb::velocypack;
using namespace arangodb::rest;
State::State(std::string const& endpoint)
: _vocbase(nullptr),
_endpoint(endpoint),
_collectionsChecked(false),
_collectionsLoaded(false) {
std::shared_ptr<Buffer<uint8_t>> buf = std::make_shared<Buffer<uint8_t>>();
VPackSlice value = arangodb::basics::VelocyPackHelper::EmptyObjectValue();
buf->append(value.startAs<char const>(), value.byteSize());
if (!_log.size()) {
_log.push_back(log_t(arangodb::consensus::index_t(0), term_t(0), arangodb::consensus::id_t(0), buf));
}
}
State::~State() {}
bool State::persist(arangodb::consensus::index_t index, term_t term, arangodb::consensus::id_t lid,
arangodb::velocypack::Slice const& entry) {
Builder body;
body.add(VPackValue(VPackValueType::Object));
std::ostringstream i_str;
i_str << std::setw(20) << std::setfill('0') << index;
body.add("_key", Value(i_str.str()));
body.add("term", Value(term));
body.add("leader", Value((uint32_t)lid));
body.add("request", entry);
body.close();
TRI_ASSERT(_vocbase != nullptr);
auto transactionContext =
std::make_shared<StandaloneTransactionContext>(_vocbase);
SingleCollectionTransaction trx (
transactionContext, "log", TRI_TRANSACTION_WRITE);
int res = trx.begin();
if (res != TRI_ERROR_NO_ERROR) {
THROW_ARANGO_EXCEPTION(res);
}
OperationResult result = trx.insert("log", body.slice(), _options);
res = trx.finish(result.code);
return (res == TRI_ERROR_NO_ERROR);
}
//Leader
std::vector<arangodb::consensus::index_t> State::log (
query_t const& query, std::vector<bool> const& appl, term_t term, arangodb::consensus::id_t lid) {
std::vector<arangodb::consensus::index_t> idx(appl.size());
std::vector<bool> good = appl;
size_t j = 0;
MUTEX_LOCKER(mutexLocker, _logLock); // log entries must stay in order
for (auto const& i : VPackArrayIterator(query->slice())) {
if (good[j]) {
std::shared_ptr<Buffer<uint8_t>> buf =
std::make_shared<Buffer<uint8_t>>();
buf->append((char const*)i[0].begin(), i[0].byteSize());
idx[j] = _log.back().index + 1;
_log.push_back(log_t(idx[j], term, lid, buf)); // log to RAM
persist(idx[j], term, lid, i[0]); // log to disk
++j;
}
}
return idx;
}
// Follower
bool State::log(query_t const& queries, term_t term, arangodb::consensus::id_t lid,
arangodb::consensus::index_t prevLogIndex, term_t prevLogTerm) { // TODO: Throw exc
if (queries->slice().type() != VPackValueType::Array) {
return false;
}
MUTEX_LOCKER(mutexLocker, _logLock); // log entries must stay in order
for (auto const& i : VPackArrayIterator(queries->slice())) {
try {
std::shared_ptr<Buffer<uint8_t>> buf =
std::make_shared<Buffer<uint8_t>>();
buf->append((char const*)i.get("query").begin(),
i.get("query").byteSize());
_log.push_back(log_t(i.get("index").getUInt(), term, lid, buf));
persist(i.get("index").getUInt(), term, lid, i.get("query")); // to disk
} catch (std::exception const& e) {
LOG(ERR) << e.what();
}
}
return true;
}
// Get log entries from indices "start" to "end"
std::vector<log_t> State::get(arangodb::consensus::index_t start, arangodb::consensus::index_t end) const {
std::vector<log_t> entries;
MUTEX_LOCKER(mutexLocker, _logLock);
if (end == (std::numeric_limits<uint64_t>::max)()) end = _log.size() - 1;
for (size_t i = start; i <= end; ++i) {
entries.push_back(_log[i]);
}
return entries;
}
std::vector<VPackSlice> State::slices(arangodb::consensus::index_t start, arangodb::consensus::index_t end) const {
std::vector<VPackSlice> slices;
MUTEX_LOCKER(mutexLocker, _logLock);
if (end == (std::numeric_limits<uint64_t>::max)()) end = _log.size() - 1;
for (size_t i = start; i <= end; ++i) { // TODO:: Check bounds
slices.push_back(VPackSlice(_log[i].entry->data()));
}
return slices;
}
log_t const& State::operator[](arangodb::consensus::index_t index) const {
MUTEX_LOCKER(mutexLocker, _logLock);
return _log[index];
}
log_t const& State::lastLog() const {
MUTEX_LOCKER(mutexLocker, _logLock);
return _log.back();
}
bool State::setEndPoint(std::string const& endpoint) {
_endpoint = endpoint;
_collectionsChecked = false;
return true;
};
bool State::checkCollections() {
if (!_collectionsChecked) {
_collectionsChecked =
checkCollection("log") && checkCollection("election");
}
return _collectionsChecked;
}
bool State::createCollections() {
if (!_collectionsChecked) {
return (createCollection("log") && createCollection("election"));
}
return _collectionsChecked;
}
bool State::checkCollection(std::string const& name) {
if (!_collectionsChecked) {
return (
TRI_LookupCollectionByNameVocBase(_vocbase, name) != nullptr);
}
return true;
}
bool State::createCollection(std::string const& name) {
Builder body;
body.add(VPackValue(VPackValueType::Object));
body.close();
VocbaseCollectionInfo parameters(_vocbase, name.c_str(),
TRI_COL_TYPE_DOCUMENT, body.slice());
TRI_vocbase_col_t const* collection =
TRI_CreateCollectionVocBase(_vocbase, parameters, parameters.id(), true);
if (collection == nullptr) {
THROW_ARANGO_EXCEPTION_MESSAGE(TRI_errno(), "cannot create collection");
}
return true;
}
bool State::loadCollections(TRI_vocbase_t* vocbase, bool waitForSync) {
_vocbase = vocbase;
_options.waitForSync = waitForSync;
_options.silent = true;
return loadCollection("log");
}
bool State::loadCollection(std::string const& name) {
TRI_ASSERT(_vocbase != nullptr);
if (checkCollection(name)) {
auto bindVars = std::make_shared<VPackBuilder>();
bindVars->openObject();
bindVars->close();
std::string const aql(std::string("FOR l IN ") + name
+ " SORT l._key RETURN l");
arangodb::aql::Query query(false, _vocbase,
aql.c_str(), aql.size(), bindVars, nullptr,
arangodb::aql::PART_MAIN);
auto queryResult = query.execute(QueryRegistryFeature::QUERY_REGISTRY);
if (queryResult.code != TRI_ERROR_NO_ERROR) {
THROW_ARANGO_EXCEPTION_MESSAGE(queryResult.code, queryResult.details);
}
VPackSlice result = queryResult.result->slice();
if (result.isArray()) {
for (auto const& i : VPackArrayIterator(result)) {
buffer_t tmp =
std::make_shared<arangodb::velocypack::Buffer<uint8_t>>();
VPackSlice req = i.get("request");
tmp->append(req.startAs<char const>(), req.byteSize());
_log.push_back(
log_t(std::stoi(i.get(TRI_VOC_ATTRIBUTE_KEY).copyString()),
static_cast<term_t>(i.get("term").getUInt()),
static_cast<arangodb::consensus::id_t>(i.get("leader").getUInt()), tmp));
}
}
return true;
}
LOG_TOPIC (INFO, Logger::AGENCY) << "Couldn't find persisted log";
createCollections();
return false;
}
bool State::find (arangodb::consensus::index_t prevIndex, term_t prevTerm) {
MUTEX_LOCKER(mutexLocker, _logLock);
if (prevIndex > _log.size()) {
return false;
}
return _log.at(prevIndex).term == prevTerm;
}
bool State::compact () {
// get read db at lastcommit % n == 0
// save read db with key 10
// update offset in logs
// delete
return true;
}