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arangodb/arangod/Agency/Agent.cpp

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////////////////////////////////////////////////////////////////////////////////
/// 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 "Agent.h"
#include <velocypack/Iterator.h>
#include <velocypack/velocypack-aliases.h>
#include <chrono>
#include "Agency/GossipCallback.h"
#include "Basics/ConditionLocker.h"
#include "RestServer/DatabaseFeature.h"
#include "RestServer/QueryRegistryFeature.h"
#include "VocBase/vocbase.h"
using namespace arangodb::application_features;
using namespace arangodb::velocypack;
using namespace std::chrono;
namespace arangodb {
namespace consensus {
/// Agent configuration
Agent::Agent(config_t const& config)
: Thread("Agent"),
_config(config),
_lastCommitIndex(0),
_spearhead(this),
_readDB(this),
_nextCompationAfter(_config.compactionStepSize()),
_inception(std::make_unique<Inception>(this)),
_activator(nullptr),
_ready(false) {
_state.configure(this);
_constituent.configure(this);
}
/// This agent's id
std::string Agent::id() const { return _config.id(); }
/// Agent's id is set once from state machine
bool Agent::id(std::string const& id) {
bool success;
if ((success = _config.setId(id))) {
LOG_TOPIC(DEBUG, Logger::AGENCY) << "My id is " << id;
} else {
LOG_TOPIC(ERR, Logger::AGENCY)
<< "Cannot reassign id once set: My id is " << _config.id()
<< " reassignment to " << id;
}
return success;
}
/// Merge command line and persisted comfigurations
bool Agent::mergeConfiguration(VPackSlice const& persisted) {
return _config.merge(persisted); // Concurrency managed in merge
}
/// Dtor shuts down thread
Agent::~Agent() {
// Give up if constituent breaks shutdown
int counter = 0;
while (_constituent.isRunning()) {
usleep(100000);
// emit warning after 5 seconds
if (++counter == 10 * 5) {
LOG_TOPIC(FATAL, Logger::AGENCY) << "constituent thread did not finish";
FATAL_ERROR_EXIT();
}
}
shutdown();
}
/// State machine
State const& Agent::state() const {
return _state;
}
/// Start all agent thread
bool Agent::start() {
LOG_TOPIC(DEBUG, Logger::AGENCY) << "Starting agency comm worker.";
Thread::start();
return true;
}
/// Get all logs from state machine
query_t Agent::allLogs() const {
return _state.allLogs();
}
/// This agent's term
term_t Agent::term() const {
return _constituent.term();
}
/// Agency size
size_t Agent::size() const {
return _config.size();
}
/// My endpoint
std::string Agent::endpoint() const {
return _config.endpoint();
}
/// Handle voting
priv_rpc_ret_t Agent::requestVote(
term_t termOfPeer, std::string const& id, index_t lastLogIndex,
index_t lastLogTerm, query_t const& query) {
bool doIVote = _constituent.vote(termOfPeer, id, lastLogIndex, lastLogTerm);
return priv_rpc_ret_t(doIVote, this->term());
}
/// Get copy of momentary configuration
config_t const Agent::config() const {
return _config;
}
/// Leader's id
std::string Agent::leaderID() const {
return _constituent.leaderID();
}
/// Are we leading?
bool Agent::leading() const {
return _constituent.leading();
}
/// Start constituent personality
void Agent::startConstituent() {
activateAgency();
}
// Waits here for confirmation of log's commits up to index. Timeout in seconds.
bool Agent::waitFor(index_t index, double timeout) {
if (size() == 1) { // single host agency
return true;
}
// Get condition variable to notice commits
CONDITION_LOCKER(guard, _waitForCV);
// Wait until woken up through AgentCallback
while (true) {
/// success?
{
MUTEX_LOCKER(lockIndex, _ioLock);
if (_lastCommitIndex >= index) {
return true;
}
}
// timeout
if (!_waitForCV.wait(static_cast<uint64_t>(1.0e6 * timeout))) {
return false;
}
// shutting down
if (this->isStopping()) {
return false;
}
}
// We should never get here
TRI_ASSERT(false);
return false;
}
// AgentCallback reports id of follower and its highest processed index
void Agent::reportIn(std::string const& id, index_t index) {
{
// Enforce _lastCommitIndex, _readDB and compaction to progress atomically
MUTEX_LOCKER(mutexLocker, _ioLock);
// Update last acknowledged answer
_lastAcked[id] = system_clock::now();
if (index > _confirmed[id]) { // progress this follower?
_confirmed[id] = index;
}
if (index > _lastCommitIndex) { // progress last commit?
size_t n = 0;
for (auto const& i : _config.active()) {
n += (_confirmed[i] >= index);
}
// catch up read database and commit index
if (n > size() / 2) {
LOG_TOPIC(TRACE, Logger::AGENCY)
<< "Critical mass for commiting " << _lastCommitIndex + 1
<< " through " << index << " to read db";
_readDB.apply(
_state.slices(
_lastCommitIndex + 1, index), _lastCommitIndex, _constituent.term());
_lastCommitIndex = index;
if (_lastCommitIndex >= _nextCompationAfter) {
_state.compact(_lastCommitIndex);
_nextCompationAfter += _config.compactionStepSize();
}
}
}
} // MUTEX_LOCKER
{ // Wake up rest handler
CONDITION_LOCKER(guard, _waitForCV);
guard.broadcast();
}
}
/// Followers' append entries
bool Agent::recvAppendEntriesRPC(
term_t term, std::string const& leaderId, index_t prevIndex, term_t prevTerm,
index_t leaderCommitIndex, query_t const& queries) {
LOG_TOPIC(DEBUG, Logger::AGENCY) << "Got AppendEntriesRPC from "
<< leaderId << " with term " << term;
// Update commit index
if (queries->slice().type() != VPackValueType::Array) {
LOG_TOPIC(WARN, Logger::AGENCY)
<< "Received malformed entries for appending. Discarding!";
return false;
}
if (!_constituent.checkLeader(term, leaderId, prevIndex, prevTerm)) {
LOG_TOPIC(WARN, Logger::AGENCY) << "Not accepting appendEntries from "
<< leaderId;
return false;
}
size_t nqs = queries->slice().length();
// State machine, _lastCommitIndex to advance atomically
MUTEX_LOCKER(mutexLocker, _ioLock);
if (nqs > 0) {
size_t ndups = _state.removeConflicts(queries);
if (nqs > ndups) {
LOG_TOPIC(TRACE, Logger::AGENCY)
<< "Appending " << nqs - ndups << " entries to state machine. ("
<< nqs << ", " << ndups << ")";
try {
_state.log(queries, ndups);
} catch (std::exception const&) {
LOG_TOPIC(DEBUG, Logger::AGENCY)
<< "Malformed query: " << __FILE__ << __LINE__;
}
}
}
_spearhead.apply(
_state.slices(_lastCommitIndex + 1, leaderCommitIndex), _lastCommitIndex,
_constituent.term());
_readDB.apply(
_state.slices(_lastCommitIndex + 1, leaderCommitIndex), _lastCommitIndex,
_constituent.term());
_lastCommitIndex = leaderCommitIndex;
if (_lastCommitIndex >= _nextCompationAfter) {
_state.compact(_lastCommitIndex);
_nextCompationAfter += _config.compactionStepSize();
}
return true;
}
/// Leader's append entries
void Agent::sendAppendEntriesRPC() {
// _lastSent, _lastHighest and _confirmed only accessed in main thread
std::string const myid = id();
for (auto const& followerId : _config.active()) {
if (followerId != myid && leading()) {
term_t t(0);
index_t last_confirmed, lastCommitIndex;
{
MUTEX_LOCKER(mutexLocker, _ioLock);
t = this->term();
last_confirmed = _confirmed[followerId];
lastCommitIndex = _lastCommitIndex;
}
std::vector<log_t> unconfirmed = _state.get(last_confirmed);
if (unconfirmed.empty()) {
// this can only happen if the log is totally empty (I think, Max)
// and so it is OK, to skip the time check here
continue;
}
index_t highest = unconfirmed.back().index;
// _lastSent, _lastHighest: local and single threaded access
duration<double> m = system_clock::now() - _lastSent[followerId];
if (highest == _lastHighest[followerId] &&
m.count() < 0.5 * _config.minPing()) {
continue;
}
// RPC path
std::stringstream path;
path << "/_api/agency_priv/appendEntries?term=" << t << "&leaderId="
<< id() << "&prevLogIndex=" << unconfirmed.front().index
<< "&prevLogTerm=" << unconfirmed.front().term << "&leaderCommit="
<< lastCommitIndex;
// Body
Builder builder;
builder.add(VPackValue(VPackValueType::Array));
for (size_t i = 1; i < unconfirmed.size(); ++i) {
auto const& entry = unconfirmed.at(i);
builder.add(VPackValue(VPackValueType::Object));
builder.add("index", VPackValue(entry.index));
builder.add("term", VPackValue(entry.term));
builder.add("query", VPackSlice(entry.entry->data()));
builder.close();
highest = entry.index;
}
builder.close();
// Verbose output
if (unconfirmed.size() > 1) {
LOG_TOPIC(TRACE, Logger::AGENCY)
<< "Appending " << unconfirmed.size() - 1 << " entries up to index "
<< highest << " to follower " << followerId << ". Message: "
<< builder.toJson();
}
// Really leading?
if (challengeLeadership()) {
_constituent.candidate();
}
// Send request
auto headerFields =
std::make_unique<std::unordered_map<std::string, std::string>>();
arangodb::ClusterComm::instance()->asyncRequest(
"1", 1, _config.poolAt(followerId),
arangodb::rest::RequestType::POST, path.str(),
std::make_shared<std::string>(builder.toJson()), headerFields,
std::make_shared<AgentCallback>(this, followerId, highest),
0.7 * _config.minPing(), true);
// _lastSent, _lastHighest: local and single threaded access
_lastSent[followerId] = system_clock::now();
_lastHighest[followerId] = highest;
}
}
}
// Check if I am member of active agency
bool Agent::active() const {
std::vector<std::string> active = _config.active();
return (find(active.begin(), active.end(), id()) != active.end());
}
// Activate with everything I need to know
query_t Agent::activate(query_t const& everything) {
auto ret = std::make_shared<Builder>();
ret->openObject();
Slice slice = everything->slice();
if (slice.isObject()) {
if (active()) {
ret->add("success", VPackValue(false));
} else {
index_t lastCommitIndex = 0;
Slice compact = slice.get("compact");
Slice logs = slice.get("logs");
std::vector<Slice> batch;
for (auto const& q : VPackArrayIterator(logs)) {
batch.push_back(q.get("request"));
}
{
MUTEX_LOCKER(mutexLocker, _ioLock); // Atomicity
if (!compact.isEmptyArray()) {
_readDB = compact.get("readDB");
}
lastCommitIndex = _lastCommitIndex;
_readDB.apply(batch, lastCommitIndex, _constituent.term());
_spearhead = _readDB;
}
//_state.persistReadDB(everything->slice().get("compact").get("_key"));
//_state.log((everything->slice().get("logs"));
ret->add("success", VPackValue(true));
ret->add("commitId", VPackValue(lastCommitIndex));
}
} else {
LOG_TOPIC(ERR, Logger::AGENCY)
<< "Activation failed. \"Everything\" must be an object, is however "
<< slice.typeName();
}
ret->close();
return ret;
}
/// @brief Activate agency (Inception thread for multi-host, main thread else)
bool Agent::activateAgency() {
if (_config.activeEmpty()) {
size_t count = 0;
for (auto const& pair : _config.pool()) {
_config.activePushBack(pair.first);
if (++count == size()) {
break;
}
}
bool persisted = false;
try {
persisted = _state.persistActiveAgents(_config.activeToBuilder(),
_config.poolToBuilder());
} catch (std::exception const& e) {
LOG_TOPIC(FATAL, Logger::AGENCY)
<< "Failed to persist active agency: " << e.what();
}
return persisted;
}
return true;
}
/// Load persistent state called once
bool Agent::load() {
DatabaseFeature* database =
ApplicationServer::getFeature<DatabaseFeature>("Database");
auto vocbase = database->systemDatabase();
auto queryRegistry = QueryRegistryFeature::QUERY_REGISTRY;
if (vocbase == nullptr) {
LOG_TOPIC(FATAL, Logger::AGENCY) << "could not determine _system database";
FATAL_ERROR_EXIT();
}
LOG_TOPIC(DEBUG, Logger::AGENCY) << "Loading persistent state.";
if (!_state.loadCollections(vocbase, queryRegistry, _config.waitForSync())) {
LOG_TOPIC(DEBUG, Logger::AGENCY)
<< "Failed to load persistent state on startup.";
}
if (size() > 1) {
_inception->start();
}
LOG_TOPIC(DEBUG, Logger::AGENCY) << "Reassembling spearhead and read stores.";
_spearhead.apply(
_state.slices(_lastCommitIndex + 1), _lastCommitIndex, _constituent.term());
{
CONDITION_LOCKER(guard, _appendCV);
guard.broadcast();
}
reportIn(id(), _state.lastLog().index);
LOG_TOPIC(DEBUG, Logger::AGENCY) << "Starting spearhead worker.";
if (size() == 1 || !this->isStopping()) {
_spearhead.start();
_readDB.start();
}
TRI_ASSERT(queryRegistry != nullptr);
if (size() == 1) {
activateAgency();
}
if (size() == 1 || !this->isStopping()) {
_constituent.start(vocbase, queryRegistry);
}
if (size() == 1 || (!this->isStopping() && _config.supervision())) {
LOG_TOPIC(DEBUG, Logger::AGENCY) << "Starting cluster sanity facilities";
_supervision.start(this);
}
return true;
}
/// Still leading? Under MUTEX from ::read or ::write
bool Agent::challengeLeadership() {
size_t good = 0;
for (auto const& i : _lastAcked) {
duration<double> m = system_clock::now() - i.second;
if (0.9 * _config.minPing() > m.count()) {
++good;
}
}
return (good < size() / 2); // not counting myself
}
/// Get last acknowledged responses on leader
query_t Agent::lastAckedAgo() const {
std::map<std::string, TimePoint> lastAcked;
{
MUTEX_LOCKER(mutexLocker, _ioLock);
lastAcked = _lastAcked;
}
auto ret = std::make_shared<Builder>();
ret->openObject();
if (leading()) {
for (auto const& i : lastAcked) {
ret->add(i.first, VPackValue(
1.0e-2 * std::floor(
(i.first!=id() ?
duration<double>(system_clock::now()-i.second).count()*100.0
: 0.0))));
}
}
ret->close();
return ret;
}
trans_ret_t Agent::transact(query_t const& queries) {
arangodb::consensus::index_t maxind = 0; // maximum write index
auto leader = _constituent.leaderID();
if (leader != id()) {
return trans_ret_t(false, leader);
}
// Apply to spearhead and get indices for log entries
auto qs = queries->slice();
auto ret = std::make_shared<arangodb::velocypack::Builder>();
size_t failed = 0;
ret->openArray();
{
MUTEX_LOCKER(mutexLocker, _ioLock);
// Only leader else redirect
if (challengeLeadership()) {
_constituent.candidate();
return trans_ret_t(false, NO_LEADER);
}
for (const auto& query : VPackArrayIterator(qs)) {
if (query[0].isObject()) {
if(_spearhead.apply(query)) {
maxind = _state.log(query[0], term());
ret->add(VPackValue(maxind));
} else {
ret->add(VPackValue(0));
++failed;
}
} else if (query[0].isString()) {
_spearhead.read(query, *ret);
}
}
// (either no writes or all preconditions failed)
if (maxind == 0) {
ret->clear();
ret->openArray();
for (const auto& query : VPackArrayIterator(qs)) {
if (query[0].isObject()) {
ret->add(VPackValue(0));
} else if (query[0].isString()) {
_readDB.read(query, *ret);
}
}
}
}
ret->close();
// Report that leader has persisted
reportIn(id(), maxind);
return trans_ret_t(true, id(), maxind, failed, ret);
}
/// Write new entries to replicated state and store
write_ret_t Agent::write(query_t const& query) {
std::vector<bool> applied;
std::vector<index_t> indices;
auto leader = _constituent.leaderID();
if (leader != id()) {
return write_ret_t(false, leader);
}
// Apply to spearhead and get indices for log entries
{
MUTEX_LOCKER(mutexLocker, _ioLock);
// Only leader else redirect
if (challengeLeadership()) {
_constituent.candidate();
return write_ret_t(false, NO_LEADER);
}
applied = _spearhead.apply(query);
indices = _state.log(query, applied, term());
}
// Maximum log index
index_t maxind = 0;
if (!indices.empty()) {
maxind = *std::max_element(indices.begin(), indices.end());
}
// Report that leader has persisted
reportIn(id(), maxind);
return write_ret_t(true, id(), applied, indices);
}
/// Read from store
read_ret_t Agent::read(query_t const& query) {
auto leader = _constituent.leaderID();
if (leader != id()) {
return read_ret_t(false, leader);
}
MUTEX_LOCKER(mutexLocker, _ioLock);
// Only leader else redirect
if (challengeLeadership()) {
_constituent.candidate();
return read_ret_t(false, NO_LEADER);
}
// Retrieve data from readDB
auto result = std::make_shared<arangodb::velocypack::Builder>();
std::vector<bool> success = _readDB.read(query, result);
return read_ret_t(true, _constituent.leaderID(), success, result);
}
/// Send out append entries to followers regularly or on event
void Agent::run() {
CONDITION_LOCKER(guard, _appendCV);
using namespace std::chrono;
auto tp = system_clock::now();
// Only run in case we are in multi-host mode
while (!this->isStopping() && size() > 1) {
// Leader working only
if (leading()) {
// Append entries to followers
sendAppendEntriesRPC();
// Don't panic
_appendCV.wait(1000);
// Detect faulty agent and replace
// if possible and only if not already activating
if (duration<double>(system_clock::now() - tp).count() > 10.0) {
detectActiveAgentFailures();
tp = system_clock::now();
}
} else {
_appendCV.wait(1000000);
updateConfiguration();
}
}
}
void Agent::reportActivated(
std::string const& failed, std::string const& replacement, query_t state) {
term_t myterm;
if (state->slice().get("success").getBoolean()) {
{
MUTEX_LOCKER(mutexLocker, _ioLock);
_confirmed.erase(failed);
auto commitIndex = state->slice().get("commitId").getNumericValue<index_t>();
_confirmed[replacement] = commitIndex;
_lastAcked[replacement] = system_clock::now();
_config.swapActiveMember(failed, replacement);
myterm = _constituent.term();
}
{
MUTEX_LOCKER(actLock, _activatorLock);
if (_activator->isRunning()) {
_activator->beginShutdown();
}
_activator.reset(nullptr);
}
} else {
MUTEX_LOCKER(mutexLocker, _ioLock);
myterm = _constituent.term();
}
// Agency configuration
auto agency = std::make_shared<Builder>();
agency->openArray();
agency->openArray();
agency->openObject();
agency->add(".agency", VPackValue(VPackValueType::Object));
agency->add("term", VPackValue(myterm));
agency->add("id", VPackValue(id()));
agency->add("active", _config.activeToBuilder()->slice());
agency->add("pool", _config.poolToBuilder()->slice());
agency->close();
agency->close();
agency->close();
agency->close();
write(agency);
// Notify inactive pool
notifyInactive();
}
void Agent::failedActivation(
std::string const& failed, std::string const& replacement) {
MUTEX_LOCKER(actLock, _activatorLock);
_activator.reset(nullptr);
}
void Agent::detectActiveAgentFailures() {
// Detect faulty agent if pool larger than agency
std::map<std::string, TimePoint> lastAcked;
{
MUTEX_LOCKER(mutexLocker, _ioLock);
lastAcked = _lastAcked;
}
MUTEX_LOCKER(actLock, _activatorLock);
if (_activator != nullptr) {
return;
}
if (_config.poolSize() > _config.size()) {
std::vector<std::string> active = _config.active();
for (auto const& id : active) {
if (id != this->id()) {
auto ds = duration<double>(
system_clock::now() - lastAcked.at(id)).count();
if (ds > 180.0) {
std::string repl = _config.nextAgentInLine();
LOG_TOPIC(DEBUG, Logger::AGENCY) << "Active agent " << id << " has failed. << "
<< repl << " will be promoted to active agency membership";
// Guarded in ::
_activator = std::make_unique<AgentActivator>(this, id, repl);
_activator->start();
return;
}
}
}
}
}
void Agent::updateConfiguration() {
// First ask last know leader
}
/// Orderly shutdown
void Agent::beginShutdown() {
Thread::beginShutdown();
// Stop supervision
if (_config.supervision()) {
_supervision.beginShutdown();
}
// Stop constituent and key value stores
_constituent.beginShutdown();
_spearhead.beginShutdown();
_readDB.beginShutdown();
// Wake up all waiting rest handlers
{
CONDITION_LOCKER(guardW, _waitForCV);
guardW.broadcast();
}
// Wake up run
{
CONDITION_LOCKER(guardA, _appendCV);
guardA.broadcast();
}
}
void Agent::prepareLead() {
// Key value stores
rebuildDBs();
// Reset last acknowledged
{
MUTEX_LOCKER(mutexLocker, _ioLock);
for (auto const& i : _config.active()) {
_lastAcked[i] = system_clock::now();
}
_leaderSince = system_clock::now();
}
}
/// Becoming leader
void Agent::lead() {
// Wake up run
{
CONDITION_LOCKER(guard, _appendCV);
guard.broadcast();
}
// Agency configuration
term_t myterm;
{
MUTEX_LOCKER(mutexLocker, _ioLock);
myterm = _constituent.term();
}
auto agency = std::make_shared<Builder>();
agency->openArray();
agency->openArray();
agency->openObject();
agency->add(".agency", VPackValue(VPackValueType::Object));
agency->add("term", VPackValue(myterm));
agency->add("id", VPackValue(id()));
agency->add("active", _config.activeToBuilder()->slice());
agency->add("pool", _config.poolToBuilder()->slice());
agency->close();
agency->close();
agency->close();
agency->close();
write(agency);
// Notify inactive pool
notifyInactive();
}
// When did we take on leader ship?
TimePoint const& Agent::leaderSince() const {
return _leaderSince;
}
// Notify inactive pool members of configuration change()
void Agent::notifyInactive() const {
std::map<std::string, std::string> pool = _config.pool();
std::string path = "/_api/agency_priv/inform";
Builder out;
out.openObject();
out.add("term", VPackValue(term()));
out.add("id", VPackValue(id()));
out.add("active", _config.activeToBuilder()->slice());
out.add("pool", _config.poolToBuilder()->slice());
out.add("min ping", VPackValue(_config.minPing()));
out.add("max ping", VPackValue(_config.maxPing()));
out.close();
for (auto const& p : pool) {
if (p.first != id()) {
auto headerFields =
std::make_unique<std::unordered_map<std::string, std::string>>();
arangodb::ClusterComm::instance()->asyncRequest(
"1", 1, p.second, arangodb::rest::RequestType::POST,
path, std::make_shared<std::string>(out.toJson()), headerFields,
nullptr, 1.0, true);
}
}
}
void Agent::updatePeerEndpoint(query_t const& message) {
VPackSlice slice = message->slice();
if (!slice.isObject() || slice.length() == 0) {
THROW_ARANGO_EXCEPTION_MESSAGE(
TRI_ERROR_AGENCY_INFORM_MUST_BE_OBJECT,
std::string("Inproper greeting: ") + slice.toJson());
}
std::string uuid, endpoint;
try {
uuid = slice.keyAt(0).copyString();
} catch (std::exception const& e) {
THROW_ARANGO_EXCEPTION_MESSAGE(
TRI_ERROR_AGENCY_INFORM_MUST_BE_OBJECT,
std::string("Cannot deal with UUID: ") + e.what());
}
try {
endpoint = slice.valueAt(0).copyString();
} catch (std::exception const& e) {
THROW_ARANGO_EXCEPTION_MESSAGE(
TRI_ERROR_AGENCY_INFORM_MUST_BE_OBJECT,
std::string("Cannot deal with UUID: ") + e.what());
}
_config.updateEndpoint(uuid, endpoint);
}
void Agent::notify(query_t const& message) {
VPackSlice slice = message->slice();
if (!slice.isObject()) {
THROW_ARANGO_EXCEPTION_MESSAGE(
TRI_ERROR_AGENCY_INFORM_MUST_BE_OBJECT,
std::string("Inform message must be an object. Incoming type is ") +
slice.typeName());
}
if (!slice.hasKey("id") || !slice.get("id").isString()) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_AGENCY_INFORM_MUST_CONTAIN_ID);
}
if (!slice.hasKey("term")) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_AGENCY_INFORM_MUST_CONTAIN_TERM);
}
_constituent.update(slice.get("id").copyString(),
slice.get("term").getUInt());
if (!slice.hasKey("active") || !slice.get("active").isArray()) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_AGENCY_INFORM_MUST_CONTAIN_ACTIVE);
}
if (!slice.hasKey("pool") || !slice.get("pool").isObject()) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_AGENCY_INFORM_MUST_CONTAIN_POOL);
}
if (!slice.hasKey("min ping") || !slice.get("min ping").isNumber()) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_AGENCY_INFORM_MUST_CONTAIN_POOL);
}
if (!slice.hasKey("max ping") || !slice.get("max ping").isNumber()) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_AGENCY_INFORM_MUST_CONTAIN_POOL);
}
_config.update(message);
_state.persistActiveAgents(_config.activeToBuilder(),
_config.poolToBuilder());
}
// Rebuild key value stores
bool Agent::rebuildDBs() {
MUTEX_LOCKER(mutexLocker, _ioLock);
_spearhead.apply(_state.slices(_lastCommitIndex + 1), _lastCommitIndex,
_constituent.term());
_readDB.apply(_state.slices(_lastCommitIndex + 1), _lastCommitIndex,
_constituent.term());
return true;
}
/// Last commit index
arangodb::consensus::index_t Agent::lastCommitted() const {
MUTEX_LOCKER(mutexLocker, _ioLock);
return _lastCommitIndex;
}
/// Last commit index
void Agent::lastCommitted(arangodb::consensus::index_t lastCommitIndex) {
MUTEX_LOCKER(mutexLocker, _ioLock);
_lastCommitIndex = lastCommitIndex;
}
/// Last log entry
log_t Agent::lastLog() const { return _state.lastLog(); }
/// Get spearhead
Store const& Agent::spearhead() const { return _spearhead; }
/// Get readdb
Store const& Agent::readDB() const { return _readDB; }
/// Rebuild from persisted state
Agent& Agent::operator=(VPackSlice const& compaction) {
// Catch up with compacted state
MUTEX_LOCKER(mutexLocker, _ioLock);
_spearhead = compaction.get("readDB");
_readDB = compaction.get("readDB");
// Catch up with commit
try {
_lastCommitIndex = std::stoul(compaction.get("_key").copyString());
} catch (std::exception const& e) {
LOG_TOPIC(ERR, Logger::AGENCY) << e.what() << " " << __FILE__ << __LINE__;
}
// Schedule next compaction
_nextCompationAfter = _lastCommitIndex + _config.compactionStepSize();
return *this;
}
/// Are we still starting up?
bool Agent::booting() { return (!_config.poolComplete()); }
/// We expect an object as follows {id:<id>,endpoint:<endpoint>,pool:{...}}
/// key: uuid value: endpoint
/// Lock configuration and compare
/// Add whatever is missing in our list.
/// Compare whatever is in our list already. (ASSERT identity)
/// If I know more immediately contact peer with my list.
query_t Agent::gossip(query_t const& in, bool isCallback, size_t version) {
LOG_TOPIC(DEBUG, Logger::AGENCY) << "Incoming gossip: "
<< in->slice().toJson();
VPackSlice slice = in->slice();
if (!slice.isObject()) {
THROW_ARANGO_EXCEPTION_MESSAGE(
20001,
std::string("Gossip message must be an object. Incoming type is ") +
slice.typeName());
}
if (!slice.hasKey("id") || !slice.get("id").isString()) {
THROW_ARANGO_EXCEPTION_MESSAGE(
20002, "Gossip message must contain string parameter 'id'");
}
if (!slice.hasKey("endpoint") || !slice.get("endpoint").isString()) {
THROW_ARANGO_EXCEPTION_MESSAGE(
20003, "Gossip message must contain string parameter 'endpoint'");
}
std::string endpoint = slice.get("endpoint").copyString();
if (isCallback) {
_inception->reportVersionForEp(endpoint, version);
}
LOG_TOPIC(TRACE, Logger::AGENCY)
<< "Gossip " << ((isCallback) ? "callback" : "call") << " from "
<< endpoint;
if (!slice.hasKey("pool") || !slice.get("pool").isObject()) {
THROW_ARANGO_EXCEPTION_MESSAGE(
20003, "Gossip message must contain object parameter 'pool'");
}
VPackSlice pslice = slice.get("pool");
LOG_TOPIC(TRACE, Logger::AGENCY) << "Received gossip " << slice.toJson();
std::map<std::string, std::string> incoming;
for (auto const& pair : VPackObjectIterator(pslice)) {
if (!pair.value.isString()) {
THROW_ARANGO_EXCEPTION_MESSAGE(
20004, "Gossip message pool must contain string parameters");
}
incoming[pair.key.copyString()] = pair.value.copyString();
}
query_t out = std::make_shared<Builder>();
{
VPackObjectBuilder b(out.get());
std::vector<std::string> gossipPeers = _config.gossipPeers();
if (!gossipPeers.empty()) {
try {
_config.eraseFromGossipPeers(endpoint);
} catch (std::exception const& e) {
LOG_TOPIC(ERR, Logger::AGENCY)
<< __FILE__ << ":" << __LINE__ << " " << e.what();
}
}
size_t counter = 0;
for (auto const& i : incoming) {
/// more data than pool size: fatal!
if (++counter > _config.poolSize()) {
LOG_TOPIC(FATAL, Logger::AGENCY)
<< "Too many peers in pool: " << counter << ">" << _config.poolSize();
FATAL_ERROR_EXIT();
}
/// disagreement over pool membership: fatal!
if (!_config.addToPool(i)) {
LOG_TOPIC(FATAL, Logger::AGENCY) << "Discrepancy in agent pool!";
FATAL_ERROR_EXIT();
}
}
if (!isCallback) { // no gain in callback to a callback.
std::map<std::string, std::string> pool = _config.pool();
out->add("endpoint", VPackValue(_config.endpoint()));
out->add("id", VPackValue(_config.id()));
out->add(VPackValue("pool"));
{
VPackObjectBuilder bb(out.get());
for (auto const& i : pool) {
out->add(i.first, VPackValue(i.second));
}
}
}
}
LOG_TOPIC(TRACE, Logger::AGENCY) << "Answering with gossip "
<< out->slice().toJson();
return out;
}
void Agent::reportMeasurement(query_t const& query) {
if (_inception != nullptr) {
_inception->reportIn(query);
}
}
void Agent::resetRAFTTimes(double min_timeout, double max_timeout) {
_config.pingTimes(min_timeout,max_timeout);
}
void Agent::ready(bool b) {
// From main thread of Inception
_ready = b;
}
bool Agent::ready() const {
if (size() == 1) {
return true;
}
return _ready;
}
}} // namespace
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