Heroku: Suitable for a Real-Time Game Server? - heroku

I am trying to run a real-time game server on Heroku using Java/Netty. The game server uses a non-standard port for communication (4876/tcp). I have built the game client using Unity3D. The game client communicates with the game server using a binary protocol (i.e. it is not using HTTP).
Is it possible for me to host this on Heroku? Heroku looks like it can only host web apps on port 80 or 443 (i.e. the web process in the procfile).
To complicate things slightly I also have a web services app built using Java/Embedded Jetty which needs to be able to communicate with the game client and the real-time game server which I also want to host on Heroku. Is this possible because I know there can be no inter-process communication? What if I create two seperate apps (one fore web services and one for real-time game server) on Heroku?

As of the time of this answer, heroku only supports http and hptts as you have noticed.
You could try modifying your game to use http as a transport for the binary protocol.

Related

Can we host a host websocket server in cloud as proxy/relay server to redirect websocket traffic from local network

[This post has been updated with a possible approach, which is added to the bottom]
I am trying to create a web socket connection between two devices((A). chrome in different computer and (B) a raspberry pi) in different networks. Thus, i can send video data over websockets. However, I cannot port forward the network of my router to expose my local IP to the network, thus, I can't send the data right away.
Figure below explains the architechture.
Thus ,I am trying to implement a logic so that Device A websockets the public ws of the cloud while, the cloud actually gets the data from Device B.So Device A websockets device B indirectly.
Device A<==>Cloud Server<==>Device B
The cloud could be something like a proxy or a relay websocket server.
The video feed needs to be sent in real time,
Please suggest how can i proceed with it.
Additional note, i have acquired an instance of digitalocean as VPS, following the blog Accessing home services from anywhere, without port forwarding! but not sure how to proceed.
Update(11th Nov,2019):
I am planning to use a websocket server on DigitalOcean instance(droplet),which would be listening to my local IP/port of my raspberry pi.And this VPS would act as a websocket server,which would redirect the traffic.
However, I am unsure how to use the same.And need your kind suggestions.

Game server with ZMQ sockets

I tried to write a game server with ZMQ sockets. The server is using a ZMQ_REP socket and the client a ZMQ_REQ socket.
This works only if one client is connected. If I connect a second client then communication breaks between the server and the first client.
Which server <-> client pattern works for one server and multiple clients?
for servers, you want to use ROUTER, and for clients, DEALER. There are a lot of examples of this in the ZeroMQ Guide. It's worth reading through that (or buy the book) and learning the different patterns, as you try simple models of your own. Don't try to build anything too complex to start with.

Node.js TCP Socket Server on the Cloud [Heroku/AppFog]

Is is possible to run a Node.js TCP Socket oriented application on the Cloud, more specifically on Heroku or AppFog.
It's not going to be a web application, but a server for access with a client program. The basic idea is to use the capabilities of the Cloud - scaling and an easy to use platform.
I know that such application could easily run on IaaS like Amazon AWS, but I would really like to take advantage of the PaaS features of Heroku or AppFog.
I am reasonably sure that doesn't answer the question at hand: "Is is possible to run a Node.js TCP Socket oriented application". All PaaS companies (including Nodejitsu) support HTTP[S]-only reverse proxies for incoming connections.
Generally with node.js + any PaaS with a socket oriented connection you want to use WebSockets, but:
Heroku does not support WebSockets and will only hold open your connection for 55-seconds (see: https://devcenter.heroku.com/articles/http-routing#timeouts)
AppFog does not support WebSockets, but I'm not sure how they handle long-held HTTP connections.
Nodejitsu supports WebSockets and will hold your connections open until closed or reset. Our node.js powered reverse-proxies make this very cheap for us.
We have plans to support front-facing TCP load-balancing with custom ports in the future. Stay tuned!
AppFog and Heroku give your app a single arbitrary port to listen on which is port mapped from port 80. You don't get to pick your port. If you need to keep a connection open for extended periods of time see my edit below. If your client does not need to maintain and open connection you should consider creating a restful API which emits json for your client app to consume. Port 80 is more than adequate for this and Node.js and Express make a superb combo for creating APIs on paas.
AppFog
https://docs.appfog.com/languages/node#node-walkthrough
var port = process.env.VCAP_APP_PORT || 5000;
Heroku
https://devcenter.heroku.com/articles/nodejs
var port = process.env.PORT || 5000;
EDIT: As mentioned by indexzero, AppFog and Heroku support http[s] only and close long held connections. AppFog will keep the connection open as long as there is activity. This can be worked around by using Socket.io or a third party solutions like Pusher
// Socket.io server
var io = require('socket.io').listen(port);
...
io.configure(function () {
io.set("transports", ["xhr-polling"]);
io.set("polling duration", 12);
});
tl;dr - with the current state of the world, it's simply not possible; you must purchase a virtual machine with its own public IP address.
All PaaS providers I've found have an HTTP router in front of all of their applications. This allows them to house hundreds of thousands of applications under a single IP address, vastly improving scalability, and hence – how they offer application hosting for free. So in the HTTP case, the Hostname header is used to uniquely identify applications.
In the TCP case however, an IP address must be used to identify an application. Therefore, in order for this to work, PaaS providers would be forced to allocate you one from their IPv4 range. This would not scale for two main reasons: the IPv4 address space having been completely exhausted and the slow pace of "legacy" networks would make it hard to physically move VMs. ("legacy" networks refer to standard/non-SDN networks.)
The solution to these two problems are IPv6 and SDN, though I foresee ubiquitous SDN arriving before IPv6 does – which could then be used to solve the various IPv4 problems. Amazon already use SDN in their datacenters though there is still a long way to go. In the meantime, just purchase a virtual machine/linux container instance with a public IP address and run your TCP servers there.

Are WebSockets really meant to be handled by Web servers?

The WebSocket standard hasn't been ratified yet, however from the draft it appears that the technology is meant to be implemented in Web servers. pywebsocket implements a WebSocket server which can be dedicated or loaded as Apache plugin.
So what I am am wondering is: what's the ideal use of WebSockets? Does it make any sense to implement a service using as dedicated WebSocket servers or is it better to rethink it to run on top of WebSocket-enabled Web server?
The WebSocket protocol was designed with three models in mind:
A WebSocket server running completely separately from any web server.
A WebSocket server running separately from a web server, but with traffic proxied to the websocket server from the web server (allowing websocket and HTTP traffic to co-exist on the same port)
A WebSocket server running as a plugin in the web server.
The model you pick really depends on the application you are trying to build and some other constraints that may limit your choices.
For example, if your application is going to be served from a single web server and the WebSocket connection will always be back to that same server, then it probably makes sense to just run the WebSocket server as a plugin/module in the web server.
On the other hand if you have a general WebSocket service that is usable from many different web sites (for example, you could have continuous low-latency traffic updates served from a WebSocket server), then you probably want to run the WebSocket server separate from any web server.
Basically, the tighter the integration between your WebSocket service and your web service, the more likely you will want to run them together and on the same port.
There are some constraints that may force one model or another:
If you control the server(s) but not the incoming firewall rules, then you probably have no choice but to run the WebSocket server on the same port(s) as your HTTP/HTTPS server (e.g. 80 and 443). In which case you will have to use a web server plugin or proxy to the real WebSocket server.
On the other hand, if you do not have super-user permission on the server where you are running the WebSocket server, then you will probably not be able to use ports 80 and 443 (below 1024 is generally a privileged port range) and in that case it really doesn't matter whether you run the HTTP/S and WebSocket servers on the same port or not.
If you have cookie based authentication (such as OAuth) in the web server and you would like to re-use this for the WebSocket connections then you will probably want to run them together (special case of tight integration).

Ruby: How to serve static HTML and an EventMachine WebSocket server from the same application?

I'm writing a simple chat application. The only "front-end" required is a single html file, a javascript file, and a few stylesheets. The majority of the application is the server-side EventMachine WebSocket server.
I'm also trying to host this on Heroku.
I currently have a sinatra app that just serves the static files, and a separate app that serves the WebSocket server (on a different port).
Is there a way I can combine these so that I can start up one application which serves/responds to port 80 (for the static files) and another port for the WebSocket server?
It's probably not a good idea to have your WebSocket server run on a different port. WebSockets run on port 80 specifically because that port is not blocked on most networks. If you use a different port, you will find users behind some firewalls unable to use your application.
Running your event server separate from your web server is probably the best way to go.
If you want something a bit more experimental, Goliath has WebSocket support in the master branch and can also serve the needed resources. If you look in the examples directory there is a WebSocket server that also serves it's HTML page.

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