/**
* 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 {
