function broker_task()
{
// Prepare our context and sockets
$context = new ZMQContext();
$frontend = new ZMQSocket($context, ZMQ::SOCKET_ROUTER);
$backend = new ZMQSocket($context, ZMQ::SOCKET_ROUTER);
$frontend->bind("tcp://*:5555");
$backend->bind("tcp://*:5556");
// Initialize poll set
$poll = new ZMQPoll();
$poll->add($frontend, ZMQ::POLL_IN);
$poll->add($backend, ZMQ::POLL_IN);
$read = $write = array();
while (true) {
$events = $poll->poll($read, $write);
foreach ($read as $socket) {
$zmsg = new Zmsg($socket);
$zmsg->recv();
if ($socket === $frontend) {
$zmsg->push("W");
$zmsg->set_socket($backend)->send();
} elseif ($socket === $backend) {
$zmsg->pop();
$zmsg->push("C");
$zmsg->set_socket($frontend)->send();
}
}
}
}
private function sendCommand($command, $msg = null)
{
if (!$msg) {
$msg = new Zmsg();
}
$msg->push($command);
$msg->push(Commands::W_WORKER);
$msg->push("");
if ($this->verbose) {
printf("I: sending `%s` to broker %s", $command, PHP_EOL);
echo $msg->__toString(), PHP_EOL;
}
$msg->set_socket($this->socket)->send();
}
/**
* Send request to broker
* Takes ownership of request message and destroys it when sent.
*
* @param string $service
* @param Zmsg $request
*/
public function send($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(MDPC_CLIENT);
$request->push("");
if ($this->verbose) {
printf("I: send request to '%s' service: %s", $service, PHP_EOL);
echo $request->__toString();
}
$request->set_socket($this->client)->send();
}
public function send($data)
{
$msg = new Zmsg($this->socket);
$msg->push($data);
$msg->wrap(sprintf("%.0f", microtime(1) * 1000));
$msg->send(true);
}
/**
* Process message sent to us by a worker
*
* @param string $sender
* @param Zmsg $msg
*/
public function worker_process($sender, $msg)
{
$command = $msg->pop();
$worker_ready = isset($this->workers[$sender]);
$worker = $this->worker_require($sender);
if ($command == MDPW_READY) {
if ($worker_ready) {
$this->worker_delete($worker, true);
// Not first command in session
} else {
if (strlen($sender) >= 4 && substr($sender, 0, 4) == 'mmi.') {
$this->worker_delete($worker, true);
} else {
// Attach worker to service and mark as idle
$service_frame = $msg->pop();
$worker->service = $this->service_require($service_frame);
$worker->service->workers++;
$this->worker_waiting($worker);
}
}
} else {
if ($command == MDPW_REPLY) {
if ($worker_ready) {
// 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(MDPC_CLIENT);
$msg->wrap($client, "");
$msg->set_socket($this->socket)->send();
$this->worker_waiting($worker);
} else {
$this->worker_delete($worker, true);
}
} else {
if ($command == MDPW_HEARTBEAT) {
if ($worker_ready) {
$worker->expiry = microtime(true) + HEARTBEAT_EXPIRY / 1000;
} else {
$this->worker_delete($worker, true);
}
} else {
if ($command == MDPW_DISCONNECT) {
$this->worker_delete($worker, true);
} else {
echo "E: invalid input message", PHP_EOL, $msg->__toString();
}
}
}
}
}
/**
* Send request to broker and get reply by hook or crook
* Takes ownership of request message and destroys it when sent.
* Returns the reply message or NULL if there was no reply.
*
* @param string $service
* @param Zmsg $request
* @param string $client
* @return Zmsg
*/
public function send($service, Zmsg $request)
{
// Prefix request with protocol frames
// Frame 1: "MDPCxy" (six bytes, MDP/Client
// Frame 2: Service name (printable string)
$request->push($service);
$request->push(MDPC_CLIENT);
if ($this->verbose) {
printf("I: send request to '%s' service:", $service);
echo $request->__toString();
}
$retries_left = $this->retries;
$read = $write = array();
while ($retries_left) {
$request->set_socket($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) {
echo "I: received reply:", $request->__toString(), PHP_EOL;
}
// Don't try to handle errors, just assert noisily
assert($request->parts() >= 3);
$header = $request->pop();
assert($header == MDPC_CLIENT);
$reply_service = $request->pop();
assert($reply_service == $service);
return $request;
// Success
} elseif ($retries_left--) {
if ($this->verbose) {
echo "W: no reply, reconnecting...", PHP_EOL;
}
// Reconnect, and resend message
$this->connect_to_broker();
$request->send();
} else {
echo "W: permanent error, abandoning request", PHP_EOL;
break;
// Give up
}
}
}
$session = new Mdcli("tcp://localhost:5555", $verbose);
// 1. Send 'echo' request to Titanic
$request = new Zmsg();
$request->push("Hello world");
$request->push("echo");
$reply = s_service_call($session, "titanic.request", $request);
$uuid = null;
if ($reply) {
$uuid = $reply->pop();
printf("I: request UUID %s %s", $uuid, PHP_EOL);
}
// 2. Wait until we get a reply
while (true) {
usleep(100000);
$request = new Zmsg();
$request->push($uuid);
$reply = s_service_call($session, "titanic.reply", $request);
if ($reply) {
$reply_string = $reply->last();
printf("Reply: %s %s", $reply_string, PHP_EOL);
// 3. Close request
$request = new Zmsg();
$request->push($uuid);
$reply = s_service_call($session, "titanic.close", $request);
break;
} else {
echo "I: no reply yet, trying again...", PHP_EOL;
usleep(5000000);
// Try again in 5 seconds
}
}
/**
* Attempt to process a single request, return 1 if successful
*
* @param Mdcli $client
* @param string $uuid
*/
function s_service_success($client, $uuid)
{
// Load request message, service will be first frame
$filename = s_request_filename($uuid);
$fh = fopen($filename, "r");
// If the client already closed request, treat as successful
if (!$fh) {
return true;
}
$request = new Zmsg();
$request->load($fh);
fclose($fh);
$service = $request->pop();
// Use MMI protocol to check if service is available
$mmi_request = new Zmsg();
$mmi_request->push($service);
$mmi_reply = $client->send("mmi.service", $mmi_request);
$service_ok = $mmi_reply && $mmi_reply->pop() == "200";
if ($service_ok) {
$reply = $client->send($service, $request);
$filename = s_reply_filename($uuid);
$fh = fopen($filename, "w");
assert($fh);
$reply->save($fh);
fclose($fh);
return true;
}
return false;
}