void AgencyCallback::refetchAndUpdate(bool needToAcquireMutex) {
if (!_needsValue) {
// no need to pass any value to the callback
if (needToAcquireMutex) {
CONDITION_LOCKER(locker, _cv);
executeEmpty();
} else {
executeEmpty();
}
return;
}
AgencyCommResult result = _agency.getValues(key);
if (!result.successful()) {
return;
}
std::vector<std::string> kv = basics::StringUtils::split(AgencyComm::prefixPath() + key,'/');
kv.erase(std::remove(kv.begin(), kv.end(), ""), kv.end());
std::shared_ptr<VPackBuilder> newData = std::make_shared<VPackBuilder>();
newData->add(result.slice()[0].get(kv));
if (needToAcquireMutex) {
CONDITION_LOCKER(locker, _cv);
checkValue(newData);
} else {
checkValue(newData);
}
}
void ClusterFeature::start() {
// return if cluster is disabled
if (!_enableCluster) {
return;
}
ServerState::instance()->setState(ServerState::STATE_STARTUP);
// the agency about our state
AgencyComm comm;
comm.sendServerState(0.0);
std::string const version = comm.getVersion();
ServerState::instance()->setInitialized();
std::string const endpoints = AgencyComm::getEndpointsString();
ServerState::RoleEnum role = ServerState::instance()->getRole();
LOG(INFO) << "Cluster feature is turned on. Agency version: " << version
<< ", Agency endpoints: " << endpoints << ", server id: '" << _myId
<< "', internal address: " << _myAddress
<< ", role: " << ServerState::roleToString(role);
if (!_disableHeartbeat) {
AgencyCommResult result = comm.getValues("Sync/HeartbeatIntervalMs");
if (result.successful()) {
velocypack::Slice HeartbeatIntervalMs =
result.slice()[0].get(std::vector<std::string>(
{AgencyComm::prefix(), "Sync", "HeartbeatIntervalMs"}));
if (HeartbeatIntervalMs.isInteger()) {
try {
_heartbeatInterval = HeartbeatIntervalMs.getUInt();
LOG(INFO) << "using heartbeat interval value '" << _heartbeatInterval
<< " ms' from agency";
} catch (...) {
// Ignore if it is not a small int or uint
}
}
}
// no value set in agency. use default
if (_heartbeatInterval == 0) {
_heartbeatInterval = 5000; // 1/s
LOG(WARN) << "unable to read heartbeat interval from agency. Using "
<< "default value '" << _heartbeatInterval << " ms'";
}
// start heartbeat thread
_heartbeatThread = std::make_shared<HeartbeatThread>(
_agencyCallbackRegistry.get(), _heartbeatInterval * 1000, 5,
SchedulerFeature::SCHEDULER->ioService());
if (!_heartbeatThread->init() || !_heartbeatThread->start()) {
LOG(FATAL) << "heartbeat could not connect to agency endpoints ("
<< endpoints << ")";
FATAL_ERROR_EXIT();
}
while (!_heartbeatThread->isReady()) {
// wait until heartbeat is ready
usleep(10000);
}
}
AgencyCommResult result;
while (true) {
VPackBuilder builder;
try {
VPackObjectBuilder b(&builder);
builder.add("endpoint", VPackValue(_myAddress));
} catch (...) {
LOG(FATAL) << "out of memory";
FATAL_ERROR_EXIT();
}
result = comm.setValue("Current/ServersRegistered/" + _myId,
builder.slice(), 0.0);
if (!result.successful()) {
LOG(FATAL) << "unable to register server in agency: http code: "
<< result.httpCode() << ", body: " << result.body();
FATAL_ERROR_EXIT();
} else {
break;
}
sleep(1);
}
if (role == ServerState::ROLE_COORDINATOR) {
ServerState::instance()->setState(ServerState::STATE_SERVING);
} else if (role == ServerState::ROLE_PRIMARY) {
ServerState::instance()->setState(ServerState::STATE_SERVINGASYNC);
} else if (role == ServerState::ROLE_SECONDARY) {
ServerState::instance()->setState(ServerState::STATE_SYNCING);
}
}
static void raceForClusterBootstrap() {
AgencyComm agency;
auto ci = ClusterInfo::instance();
while (true) {
AgencyCommResult result = agency.getValues("Bootstrap");
if (!result.successful()) {
// Error in communication, note that value not found is not an error
LOG_TOPIC(TRACE, Logger::STARTUP)
<< "raceForClusterBootstrap: no agency communication";
sleep(1);
continue;
}
VPackSlice value = result.slice()[0].get(
std::vector<std::string>({agency.prefix(), "Bootstrap"}));
if (value.isString()) {
// key was found and is a string
if (value.copyString().find("done") != std::string::npos) {
// all done, let's get out of here:
LOG_TOPIC(TRACE, Logger::STARTUP)
<< "raceForClusterBootstrap: bootstrap already done";
return;
}
LOG_TOPIC(DEBUG, Logger::STARTUP)
<< "raceForClusterBootstrap: somebody else does the bootstrap";
sleep(1);
continue;
}
// No value set, we try to do the bootstrap ourselves:
VPackBuilder b;
b.add(VPackValue(arangodb::ServerState::instance()->getId()));
result = agency.casValue("Bootstrap", b.slice(), false, 300, 15);
if (!result.successful()) {
LOG_TOPIC(DEBUG, Logger::STARTUP)
<< "raceForClusterBootstrap: lost race, somebody else will bootstrap";
// Cannot get foot into the door, try again later:
sleep(1);
continue;
}
// OK, we handle things now, let's see whether a DBserver is there:
auto dbservers = ci->getCurrentDBServers();
if (dbservers.size() == 0) {
LOG_TOPIC(TRACE, Logger::STARTUP)
<< "raceForClusterBootstrap: no DBservers, waiting";
agency.removeValues("Bootstrap", false);
sleep(1);
continue;
}
LOG_TOPIC(DEBUG, Logger::STARTUP)
<< "raceForClusterBootstrap: race won, we do the bootstrap";
auto vocbase = DatabaseFeature::DATABASE->systemDatabase();
V8DealerFeature::DEALER->loadJavascriptFiles(vocbase, "server/bootstrap/cluster-bootstrap.js", 0);
LOG_TOPIC(DEBUG, Logger::STARTUP)
<< "raceForClusterBootstrap: bootstrap done";
b.clear();
b.add(VPackValue(arangodb::ServerState::instance()->getId() + ": done"));
result = agency.setValue("Bootstrap", b.slice(), 0);
if (result.successful()) {
return;
}
LOG_TOPIC(TRACE, Logger::STARTUP)
<< "raceForClusterBootstrap: could not indicate success";
sleep(1);
}
}