/** * Send reply, if any, to broker and wait for next request. * * @param Zmsg $reply * @return Zmsg Returns if there is a request to process */ public function recv($reply = null) { // Format and send the reply if we were provided one assert($reply || !$this->expect_reply); if ($reply) { $reply->wrap($this->reply_to); $this->send_to_broker(MDPW_REPLY, NULL, $reply); } $this->expect_reply = true; $read = $write = array(); while (true) { $poll = new ZMQPoll(); $poll->add($this->worker, ZMQ::POLL_IN); $events = $poll->poll($read, $write, $this->heartbeat); if ($events) { $zmsg = new Zmsg($this->worker); $zmsg->recv(); if ($this->verbose) { echo "I: received message from broker:", PHP_EOL; echo $zmsg->__toString(); } $this->liveness = HEARTBEAT_LIVENESS; // Don't try to handle errors, just assert noisily assert($zmsg->parts() >= 3); $zmsg->pop(); $header = $zmsg->pop(); assert($header == MDPW_WORKER); $command = $zmsg->pop(); if ($command == MDPW_REQUEST) { // We should pop and save as many addresses as there are // up to a null part, but for now, just save one... $this->reply_to = $zmsg->unwrap(); return $zmsg; // We have a request to process } else { if ($command == MDPW_HEARTBEAT) { // Do nothing for heartbeats } else { if ($command == MDPW_DISCONNECT) { $this->connect_to_broker(); } else { echo "E: invalid input message", PHP_EOL; echo $zmsg->__toString(); } } } } else { if (--$this->liveness == 0) { // poll ended on timeout, $event being false if ($this->verbose) { echo "W: disconnected from broker - retrying...", PHP_EOL; } usleep($this->reconnect * 1000); $this->connect_to_broker(); } } // Send HEARTBEAT if it's time if (microtime(true) > $this->heartbeat_at) { $this->send_to_broker(MDPW_HEARTBEAT, NULL, NULL); $this->heartbeat_at = microtime(true) + $this->heartbeat / 1000; } } }
/** * Run a self test of the Zmsg class. * * @return boolean * @todo See if assert returns */ public static function test() { $result = true; $context = new ZMQContext(); $output = new ZMQSocket($context, ZMQ::SOCKET_XREQ); $output->bind("inproc://zmsg_selftest"); $input = new ZMQSocket($context, ZMQ::SOCKET_XREP); $input->connect("inproc://zmsg_selftest"); // Test send and receive of single-part message $zmsgo = new Zmsg($output); $zmsgo->body_set("Hello"); $result &= assert($zmsgo->body() == "Hello"); $zmsgo->send(); $zmsgi = new Zmsg($input); $zmsgi->recv(); $result &= assert($zmsgi->parts() == 2); $result &= assert($zmsgi->body() == "Hello"); echo $zmsgi; // Test send and receive of multi-part message $zmsgo = new Zmsg($output); $zmsgo->body_set("Hello"); $zmsgo->wrap("address1", ""); $zmsgo->wrap("address2"); $result &= assert($zmsgo->parts() == 4); echo $zmsgo; $zmsgo->send(); $zmsgi = new Zmsg($input); $zmsgi->recv(); $result &= assert($zmsgi->parts() == 5); $zmsgi->unwrap(); $result &= assert($zmsgi->unwrap() == "address2"); $zmsgi->body_fmt("%s%s", 'W', "orld"); $result &= assert($zmsgi->body() == "World"); // Pull off address 1, check that empty part was dropped $zmsgi->unwrap(); $result &= assert($zmsgi->parts() == 1); // Check that message body was correctly modified $part = $zmsgi->pop(); $result &= assert($part == "World"); $result &= assert($zmsgi->parts() == 0); // Test load and save $zmsg = new Zmsg(); $zmsg->body_set("Hello"); $zmsg->wrap("address1", ""); $zmsg->wrap("address2"); $result &= assert($zmsg->parts() == 4); $fh = fopen(sys_get_temp_dir() . "/zmsgtest.zmsg", 'w'); $zmsg->save($fh); fclose($fh); $fh = fopen(sys_get_temp_dir() . "/zmsgtest.zmsg", 'r'); $zmsg2 = new Zmsg(); $zmsg2->load($fh); assert($zmsg2->last() == $zmsg->last()); fclose($fh); $result &= assert($zmsg2->parts() == 4); echo $result ? "OK" : "FAIL", PHP_EOL; return $result; }
$interval = INTERVAL_INIT; // Send out heartbeats at regular intervals $heartbeat_at = microtime(true) + HEARTBEAT_INTERVAL; $read = $write = array(); $cycles = 0; while (true) { $poll = new ZMQPoll(); $poll->add($worker, ZMQ::POLL_IN); $events = $poll->poll($read, $write, HEARTBEAT_INTERVAL * 1000); if ($events) { // Get message // - 3-part envelope + content -> request // - 1-part "HEARTBEAT" -> heartbeat $zmsg = new Zmsg($worker); $zmsg->recv(); if ($zmsg->parts() == 3) { // Simulate various problems, after a few cycles $cycles++; if ($cycles > 3 && rand(0, 5) == 0) { printf("I: (%s) simulating a crash%s", $identity, PHP_EOL); break; } elseif ($cycles > 3 && rand(0, 5) == 0) { printf("I: (%s) simulating CPU overload%s", $identity, PHP_EOL); sleep(5); } printf("I: (%s) normal reply - %s%s", $identity, $zmsg->body(), PHP_EOL); $zmsg->send(); $liveness = HEARTBEAT_LIVENESS; sleep(1); // Do some heavy work } elseif ($zmsg->parts() == 1 && $zmsg->body() == 'HEARTBEAT') {
/** * Returns the reply message or NULL if there was no reply. Does not * attempt to recover from a broker failure, this is not possible * without storing all unanswered requests and resending them all... * */ public function recv() { $read = $write = array(); // 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) { $msg = new Zmsg($this->client); $msg->recv(); if ($this->verbose) { echo "I: received reply:", $msg->__toString(), PHP_EOL; } // Don't try to handle errors, just assert noisily assert($msg->parts() >= 4); $msg->pop(); // empty $header = $msg->pop(); assert($header == MDPC_CLIENT); $reply_service = $msg->pop(); return $msg; // Success } else { echo "W: permanent error, abandoning request", PHP_EOL; return; // Give up } }
function server_worker() { $context = new ZMQContext(); $worker = new ZMQSocket($context, ZMQ::SOCKET_DEALER); $worker->connect("ipc://backend"); $zmsg = new Zmsg($worker); while (true) { // The DEALER socket gives us the address envelope and message $zmsg->recv(); assert($zmsg->parts() == 2); // Send 0..4 replies back $replies = rand(0, 4); for ($reply = 0; $reply < $replies; $reply++) { // Sleep for some fraction of a second usleep(rand(0, 1000) + 1); $zmsg->send(Zmsg::NOCLEAR); } } }
/** * 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 } } }
$poll->add($backend, ZMQ::POLL_IN); // Poll frontend only if we have available workers if ($queue->size()) { $poll->add($frontend, ZMQ::POLL_IN); } $events = $poll->poll($read, $write, HEARTBEAT_INTERVAL * 1000 * 1000); // microseconds if ($events > 0) { foreach ($read as $socket) { $zmsg = new Zmsg($socket); $zmsg->recv(); // Handle worker activity on backend if ($socket === $backend) { $identity = $zmsg->unwrap(); // Return reply to client if it's not a control message if ($zmsg->parts() == 1) { if ($zmsg->address() == "READY") { $queue->s_worker_delete($identity); $queue->s_worker_append($identity); } else { if ($zmsg->address() == 'HEARTBEAT') { $queue->s_worker_refresh($identity); } else { printf("E: invalid message from %s%s%s", $identity, PHP_EOL, $zmsg->__toString()); } } } else { $zmsg->set_socket($frontend)->send(); $queue->s_worker_append($identity); } } else {