Krestianstvo | Electric Clojure. Implementing a scalable Croquet VM.

Work In Progress

This repository contains the implementation of the Croquet VM (based on Krestianstvo SDK 4 and Virtual World Framework) in Electric Clojure programming language.

The big idea here is to use the Electric distributed runtime as a basis for a higher level scene graph sync abstraction for use in collaborative virtual worlds.

Here are the first steps video with a <200 LoC classic Croquet VM implementation from Krestianstvo SDK 4:

20230508.Nikolai.Electric.Krestianstvo.mp4

In <200 LoC all parts of the classic Croquet VM are implemented, including Reflector server, Virtual Time, Recursive Future Messages etc. VM is distributed in a single Electric application as a DAG.
Krestianstvo in Electric makes Croquet VM being scalable. Meaning, that previous single Reflector server can be scaled up across networks organising the fleet of Reflectors.
Internal dispatcher of the Croquet VM messages queue can be distributed across hardware threads safely.
Krestianstvo applications can be potentially run not only in web-browsers, but also in any Clojure hosted environment, scaling horizontally & vertically.

Demo prototype is running at: https://e.krestianstvo.org

Learn more about Krestianstvo SDK 4 here: https://play.krestianstvo.org

Background

Croquet is a software development kit (SDK) for use in developing collaborative virtual world applications. The Croquet software architecture is known for its radical synchronization system with the notion of virtual time.

Krestianstvo SDK 4 is the Open Source implementation of the Croquet application architecture in Functional Reactive Paradigm.

Electric Clojure is a new web development paradigm that uses a compiler to build frontend/backend network sync directly into the programming language itself.

Electric Clojure

The Virtual World Framework (VWF) is a means to connect robust 3D, immersive, entities with other entities, virtual worlds, content and users via web browsers.

Development

$ clj -A:dev -X user/main

Starting Electric compiler and server...
shadow-cljs - server version: 2.20.1 running at http://localhost:9630
shadow-cljs - nREPL server started on port 9001
[:app] Configuring build.
[:app] Compiling ...
[:app] Build completed. (224 files, 0 compiled, 0 warnings, 1.93s)

👉 App server available at http://0.0.0.0:8080

Deployment

ClojureScript optimized build, Dockerfile, Uberjar, Github actions CD to fly.io

HYPERFIDDLE_ELECTRIC_APP_VERSION=`git describe --tags --long --always --dirty`
clojure -X:build build-client          # optimized release build
clojure -X:build uberjar :jar-name "app.jar" :version '"'$HYPERFIDDLE_ELECTRIC_APP_VERSION'"'
java -DHYPERFIDDLE_ELECTRIC_SERVER_VERSION=$HYPERFIDDLE_ELECTRIC_APP_VERSION -jar app.jar

docker build --progress=plain --build-arg VERSION="$HYPERFIDDLE_ELECTRIC_APP_VERSION" -t electric-starter-app .
docker run --rm -p 7070:8080 electric-starter-app

# flyctl launch ... ? create fly app, generate fly.toml, see dashboard
# https://fly.io/apps/electric-starter-app

NO_COLOR=1 flyctl deploy --build-arg VERSION="$HYPERFIDDLE_ELECTRIC_APP_VERSION"
# https://electric-starter-app.fly.dev/

NO_COLOR=1 disables docker-cli fancy shell GUI, so that we see the full log (not paginated) in case of exception
--build-only tests the build on fly.io without deploying

Contributing