gzochi (/zoʊ-ʧi:/) is a framework for developing massively multiplayer online games. A server container provides services to deployed games, which are written in Guile Scheme, that abstract and simplify some of the most challenging and error-prone aspects of online game development: Concurrency, data persistence, and network communications. A very thin client library can be embedded to provide connectivity for client applications written in any language.
- An automatic persistence mechanism that manages game state as an object graph in which updates are tracked and persisted independently.
- A transactional execution environment that provides a consistent view of data to each thread of running game code.
- Scheduling and execution services for immediate or deferred game logic, with durability guarantees such that tasks that fail with a recoverable error can be retried, even across server restarts.
- A robust networking layer that handles client connection lifecycle, and supports both broadcast and point-to-point message delivery.
- A pluggable authentication system with plugins for Kerberos and password file-based authentication.
- A library of scalable data structures to support efficient, concurrent access to large collections of game objects.
Here's what a
gzochi application looks like:
(define-module (jeopardy!) #:use-module (gzochi) #:use-module (rnrs bytevectors)) (gzochi:define-managed-record-type button (fields (mutable flashing (serialization gzochi:boolean-serialization)))) (define (go!) (let ((msg (string->utf8 "go!!!"))) (button-flashing-set! (gzochi:get-binding "button") #t) (gzochi:send-channel-message (gzochi:get-channel "trebek") msg))) (define (schedule-reset) (let ((s (+ (random 10) 1))) (gzochi:schedule-task (gzochi:make-callback 'go! '(jeopardy!)) (* s 1000)))) (define (initialized properties) (gzochi:set-binding! "button" (make-button #f)) (gzochi:create-channel "trebek") (schedule-reset)) (define (client-disconnected session) (gzochi:leave-channel (gzochi:get-channel "trebek") session)) (define (received-message session) (let ((button (gzochi:get-binding "button"))) (if (button-flashing button) (let* ((name (gzochi:client-session-name session)) (msg (string->utf8 (simple-format #f "~A wins!" name)))) (button-flashing-set! button #f) (gzochi:send-channel-message (gzochi:get-channel "trebek") msg) (schedule-reset))))) (define (client-connected session) (gzochi:join-channel (gzochi:get-channel "trebek") session) (gzochi:make-client-session-listener (gzochi:make-callback 'received-message '(jeopardy!)) (gzochi:make-callback 'client-disconnected '(jeopardy!))))
gzochi turns this code into a network game server capable of supporting thousands of simultaneously-connected players, and transparently persists the state of all game objects so that data integrity is guaranteed — even in the event of a power failure or hard restart.
gzochi prevents race conditions and other concurrency issues by executing every task in its own transactional context, protected from modifications happening elsewhere. Write your game as a single thread, and do away with explicit synchronization:
gzochi responds to clients, schedules tasks, and resolves deadlocks for you.
How it works
Click the image link to see an architectural diagram of a game application managed by the gzochi framework. The parts of diagram colored green — namely the client application and the server-side game logic — are the parts you write. Everything else is part of the framework; use as much or as little of it as you need!
gzochi version 0.5 released
Happy new year! We're pleased to announce the next development release of the gzochi game development framework.
This release resolves a number of issues with the durability of scheduled tasks and the execution of highly concurrent application code. A new scalable, concurrent data structure has been added to the Scheme API. Several improvements have also been made to the performance of the server and the reference client implementations.
See the NEWS and README files of the individual framework components for more details. The manual has been updated to reflect all new and modified features.
DownloadTry it out! The source distribution comes with everything you need to get started building games with
gzochi. In additon to the server, source code for several reference client libraries and two complete client-server example games is included, along with detailed Texinfo and man page documentation.