6. Why this complex setup?
”Independent” decoupled parts
- Easier to test
- Easier to maintain / replace
- Each part only does one thing
Multiple languages
- There is no silver bullet
7. Messaging: ZeroMQ
"ZeroMQ is a messaging library, which allows you
to design a complex communication system
without much effort."
– Nicholas Piël
”Messaging makes everything possible!”
– Alvaro Videla, JSDay 2013 (yesterday)
11. Statistics input: External system
Seven Operators per arena, logging events.
- Shots on net, shots wide, shots blocked
- Goals and assists
- Players currently on the ice, shifts
- Penalties
- Hits
- ...and much more...
Data is transferred using XML files and http(s).
13. Parser: PHP, mongoDB
PHP: Familiar, XML processing
Doctrine ODM to share documents
with CMS system (Symfony2).
MongoDB: Different attributes/fields
depending on event type.
Shot Goal Penalty
Player Player Player
Goal section Goal section
Assists
POP, NEP (players on
ice)
Penalty reason
14. Parser: PHP, mongoDB
Possible improvements (when needed):
Scale - one parser process per game
(only changes in this component)
Alternatives (PHP based):
- Symfony2 (full-stack)
- Silex (micro)
…
16. Editorial input: Symfony2, MySQL
Multiple Operators located in different places
- Live text comments describing the events
- Data tagged with games and teams for filtering
- Flexible, adjustable, custom made functionality
- CMS also includes REST-ish API used by clients
18. Queue Controller: PHP
Decides what messages that should go where.
Isn’t this a broker!?
Yes, kind of…
- Decides which queue(s) to send to.
- No information about actual end points.
How?
19. Queue Controller: PHP
// Prepare our context and socket
$context = new ZMQContext();
// Subscribe to messages from parser
$parser = $context->getSocket(ZMQ::SOCKET_SUB);
// Connect to publishing socket
$parser->connect('tcp://192.168.0.11:9900');
// Define the channel(s) for
// delivery servers to subscribe to
$channel = $context->getSocket(ZMQ::SOCKET_PUB);
// Bind each channel to an IP and port
$channel->bind('tcp://192.168.0.12:5555');
20. Queue Controller: PHP
// All in an infinite loop
// ...
// Receive messages from the parser
$msg = $parser->recv();
// Which channels will the message go to
$recievingChannels = getChannelsForMsg($msg);
// Send message to appropriate channels
foreach ($recievingChannels as $channel) {
$channel->send($msg);
}
22. Delivery: Node.js, SockJS
Why Node.JS?
- High concurrency
- Same language as client
Why SockJS?
- Lightweight, but still fallbacks for Web Sockets
- Option to get ”raw” sockets
Alternatives:
- socket.io (or simply polling...)
http://bit.ly/143An2a
23. NodeJS server code
var server = sockjs.createServer();
server.on(‘connection’, function(conn) {
conn.on(‘data’, function(msg) {
// Check the action passed
switch (msg.action) {
// ...
// Do the corresponding thing...
// I.e. let the client join a channel
// ...
}
});
});
24. // Game event message received from Queue Controller
var gameEventMessage = ”blablabla”;
// Send a message to a client
var conn = getNextClient(clients);
conn.write(gameEventMessage);
NodeJS server code (cont.)
25. Delivery: Node.js, SockJS
SockJS client code
var sockjs = new SockJS('http://192.168.0.13:8080');
sockjs.onopen = function() {
// SockJS connection opened
};
sockjs.onmessage = function(e) {
// Message recieved
var msg = JSON.parse(e.data);
};
sockjs.onclose = function() {
// Connection closed
// Offer the user possibility to reconnect
$('button#reconnect').show();
};
29. Several versions
- Web
- Mobile version
- Mobile version for arenas (using local WiFi)
The different versions share a lot of functionality.
Clients: Symfony2, HTML5, JavaScript
32. What have we learned?
- Good to keep things separated
- Don’t over engineer the solution!
But...
...by keeping things separated you can re-engineer later –
when needed!
- Use the tools you know how to handle
- Select the most appropriate tool from your own toolchain
