ConnServer2 is a modern reimplementation of a classic MMO game server backend. The original project can be found on Github at: https://github.com/cthulhuology/ConnServer and was used in a number of production games over a number of years. ConnServer2 is a modern adaptation of the ConnServer codebase building upon the changes in web programming over the last 8 years.
Over the past few years a number of changes have occured in the ecosystem of web gaming:
* Flash has a less dominant position
* WebSockets mean that web browsers now have full bidirectional messaging
* HTML5 Canvas and WebGL mean it is possible to build rich UIs in the browser
* Faster JavaScript engines mean that more processing can be done on the front end
* JSON has won out over URL encoded strings
* Databases like PostgreSQL now natively support JSON in key/value stores
The original ConnServer code base was heavily based upon the limitations of using XMLSockets in Flash to provide full bidirectional real time communication between the browser and the server. Additionally, the ConnServer spent much of it's time processing object state on the behalf of the client, as the client couldn't be trusted to simulate entities and render at 12fps on the client. As such the original ConnServer contained an entire distributed in memory cache (similar to memcache meets mongodb) with binary blobs backed in a Postgres database.
As such the new ConnServer2 code base is going to modernize a bit and attempt to gain a bit of ground over it's predicessor. ConnServer2 will support:
* JSON as it's native messaging format
* WebSocket support will work out of the box, as well as raw TCP connections
* The new Object Server functionality will be migrated to a separate process space
* An advanced Actor model will be supported for native bots and client connections
* Multiple routing topologies will be supported, in addition to pub/sub models
Overall ConnServer2 should be slightly more robust and capable of running on substantially more cores than the original ConnServer codebase which was started over 11 years ago.
As the original ConnServer was written in C++, I am going to attempt to implement ConnServer2 in Go, http://golang.org. While the original code base exploited many advanced features of C++, the Go rewrite will attempt use all of the major features of the language. This will be the first substantial program that I am writing in Go, and I'm already finding some of the limitations of the language to be a bit more than annoying. But from Algol in funny hats to Algol in funny hats isn't such a big switch.
Most of the game logic in the original ConnServer based projects were relegated to AI bots that ran on separate servers, and were written in scripting languages that would allow for rapid modification to the working AIs. However, the original ConnServer also allowed for loading C++ libraries at runtime which could dynamically intercept and process messages on the server side. The module system required that each C++ object be versioned, and dynamic code loading required serious games with the symbol tables.
ConnServer2 will attempt to preserve the module behavior as well, however Go currently doesn't support dynamically loading packages, and so the support for new modules will be by launching new Go servers and migrating the objects from old to new. While not ideal, it will make it possible to continue to develop fast path actors while preserving the ability to keep more complex models out of the critical path.
The following is my thoughts on when I expect to have various bit generally done. All of these dates are just hand waving at the moment. I suspect the basic functionality represented in v0.1 will actually be enough to build useful systems with, but it will probably take a year to harden and tool it sufficiently well that one would actually consider using it in production.
Release v0.1 (Octoberish 2014)
* messages
* actors
* direct routing
* fanout routing
* topic routing
* rooms and announcements
* actor registry
* websockets
Release v0.2 (Novemberish 2014)
* object cache
* object persistence
Release v0.3 (Januaryish 2015)
* live upgrades
Release v0.4 (Marchish 2015)
* server to server
* automatic failover
Release v0.5 (Mayish 2015)
* tcp sockets
* bot toolkit
* object toolkit
Release v0.6 (Julyish 2015)
* ui toolkit
* management ui
Release v0.7 (Septemberish 2015)
* sample game
Release v1.0 (Octoberish 2015)
* fully operational deathstar
NB: These dates all assume that life doesn't find ways to prevent me from hacking on this occasionally.
If you are interested in the development of ConnServer2, or would like to use it for some purpose I never intended, please feel free to drop me a line at dave at dloh.org.
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