/**
* Makes sure the broker is running.
* If it isn't running method will start it.
*
* @return int Returns non false if broker is running
*/
public static function ensureBrokerRunning()
{
$client = (new Client(\Scalr::config('scalr.crontab.sockets.broker')))->setTimeout(100)->setRetries(1)->setLogger(\Scalr::getContainer()->logger('Mdp\\Client')->setLevel(\Scalr::config('scalr.crontab.log_level')))->connect();
$mmiReq = new Zmsg();
$mmiReq->push("system.healthcheck");
$mmiRep = $client->send("mmi.service", $mmiReq);
if ($mmiRep) {
$ok = $mmiRep->pop();
} else {
$ok = false;
//Make sure another broker process isn't hanging
self::terminateBroker();
//Broker has to be started in the separate process
$op = [];
$logFile = \Scalr::config('scalr.crontab.log');
exec(self::getStartBrokerCommand() . ' ' . ($logFile == '/dev/null' ? '> ' : '>> ') . escapeshellcmd($logFile) . ' 2>&1 & echo $!', $op);
$pid = intval($op[0]);
}
return $ok;
}
/**
* Send request to broker and get reply by hook or crook.
*
* Takes ownership of request message and destroys it when sent.
*
*
* @param string $service The name of the service
* @param Zmsg $request Request message
* @return Zmsg Returns the reply message or NULL if there was no reply.
*/
public function send($service, Zmsg $request)
{
// Prefix request with protocol frames
// Frame 1: "MDPCxy" (six bytes, MDP/Client)
// Frame 2: Service name (printable string)
$request->push($service);
$request->push(Mdp::CLIENT);
if ($this->verbose) {
$this->log("ZMQDEBUG", "send request to '%s' service:\n--\n%s", $service, (string) $request);
}
$retries_left = $this->retries;
$read = $write = array();
while ($retries_left) {
$request->setSocket($this->client)->send();
// Poll socket for a reply, with timeout
$poll = new ZMQPoll();
$poll->add($this->client, ZMQ::POLL_IN);
$events = $poll->poll($read, $write, $this->timeout);
// If we got a reply, process it
if ($events) {
$request->recv();
if ($this->verbose) {
$this->log("ZMQDEBUG", "received reply:\n--\n%s", $request);
}
if ($request->parts() < 3) {
throw new MdpException(sprintf("Expected more than 2 parts, but %d received", $request->parts()));
}
$header = $request->pop();
if ($header !== Mdp::CLIENT) {
throw new MdpException(sprintf("Unexpected header %s, %s is expected", $header, Mdp::CLIENT));
}
$replyService = $request->pop();
if ($replyService != $service) {
throw new MdpException(sprintf("Unexpected service %s, %s is expected.", $replyService, $service));
}
//Success
return $request;
} elseif ($retries_left--) {
if ($this->verbose) {
$this->log("WARN", "no reply, reconnecting...");
}
// Reconnect
$this->connect();
// Resend message again
$request->send();
} else {
if ($this->verbose) {
$this->log("ERROR", "permanent error, abandoning request");
break;
}
}
}
}
/**
* Process message sent to us by a worker
*
* @param string $sender The address of the worker
* @param \Scalr\System\Zmq\Zmsg $msg The message
*/
public function processWorker($sender, $msg)
{
$command = $msg->pop();
$workerReady = isset($this->workers[$sender]);
$worker = $this->fetchWorker($sender);
if ($command == Mdp::WORKER_READY) {
if ($workerReady) {
// Not first command in session
$this->deleteWorker($worker, true);
} elseif (strlen($sender) >= 4 && substr($sender, 0, 4) == 'mmi.') {
// Reserved service name
$this->deleteWorker($worker, true);
} else {
// Attach worker to service and mark as idle
$serviceFrame = $msg->pop();
$worker->service = $this->fetchService($serviceFrame);
$worker->service->workers++;
$this->waitWorker($worker);
}
} elseif ($command == Mdp::WORKER_REPLY) {
if ($workerReady) {
// Remove & save client return envelope and insert the
// protocol header and service name, then rewrap envelope.
$client = $msg->unwrap();
$msg->push($worker->service->name);
$msg->push(Mdp::CLIENT);
$msg->wrap($client, "");
$msg->setSocket($this->socket)->send();
if ($this->verbose) {
$this->log("ZMQDEBUG", "worker replied:\n--\n%s", (string) $msg);
}
$this->waitWorker($worker);
} else {
$this->deleteWorker($worker, true);
}
} elseif ($command == Mdp::WORKER_HEARTBEAT) {
if ($workerReady) {
$worker->expiry = microtime(true) + $this->heartbeatExpiry / 1000;
} else {
$this->deleteWorker($worker, true);
}
} elseif ($command == Mdp::WORKER_DISCONNECT) {
$this->deleteWorker($worker, true);
if ($this->verbose) {
$this->log("ZMQDEBUG", "disconnect worker\n--\n%s", (string) $msg);
}
} else {
if ($this->verbose) {
$this->log("ERROR", "invalid input message\n--\n%s", (string) $msg);
}
}
}
/**
* Send request to broker and get reply by hook or crook.
*
* Takes ownership of request message and destroys it when sent.
*
*
* @param string $service The name of the service
* @param Zmsg $request Request message
* @return Zmsg Returns the reply message or NULL if there was no reply.
*/
public function send($service, Zmsg $request)
{
// Prefix request with protocol frames
// Frame 0: empty (REQ emulation)
// Frame 1: "MDPCxy" (six bytes, MDP/Client x.y)
// Frame 2: Service name (printable string)
$request->push($service);
$request->push(Mdp::CLIENT);
$request->push("");
if ($this->verbose) {
$this->log('ZMQDEBUG', "send request to '%s' service:\n--\n%s", $service, (string) $request);
}
$request->setSocket($this->client)->send();
}
/**
* Checks whether service is registered with the broker
*
* @param string $serviceName optional The name of the service.
*
* @return int|bool Returns the number of registered workers if service has been registered with the broker or
* boolean FALSE otherwise
*/
public function isServiceRegistered($serviceName = null)
{
$client = (new Client(\Scalr::config('scalr.crontab.sockets.broker')))->setTimeout(1000)->setRetries(1)->setLogger(\Scalr::getContainer()->logger('Mdp\\Client')->setLevel(\Scalr::config('scalr.crontab.log_level')))->connect();
$mmiReq = new Zmsg();
$mmiReq->push($serviceName ?: $this->name);
$mmiRep = $client->send("mmi.service", $mmiReq);
if ($mmiRep) {
$code = $mmiRep->pop();
$workers = $code == '200' ? (int) $mmiRep->pop() : 0;
}
return $mmiRep && $code == '200' ? $workers : (isset($code) ? 0 : false);
}
