haskell-butler

This library provides a virtual operating system to run Haskell App. Checkout the introduction blog post.

Project Status

The goal of butler is to implement modular abstractions by simulating a traditional computer.

• Logger and Clock
• Process for supervision tree
• Storage for persistance
• Network for web application
• Websocket session for authentication
• Display for html5 gui
• Audio channel
• File upload
• File download
• Application testing
• Mailbox and notification
• Application debugging api (e.g. strace for events)
• External identity providers
• Authorization system

To validate the abstractions, the project also feature some proof of concept demos:

HTML5 GUI

Serve App behind nginx with:

upstream butler {
     server 127.0.0.1:8042;
}

server {
    location / {
      proxy_pass http://butler/;
      proxy_http_version 1.1;
      proxy_set_header Upgrade $http_upgrade;
      proxy_set_header Connection "Upgrade";
      proxy_set_header Host $host;
    }
}

Start the service with:

BUTLER_ADDR=http:8042 cabal run

Multiplayer Desktop

A window-xp clone with support for multiple "seats":

• Simple invitation system to share the session with other users.
• Dekstop with a menu and tray bar
• Window manager
• Per user pointer and audio channel
• Xterm and Vnc gateway
• Programming REPL
• Media player
• Agenda and calendar
• Games

Start the service with:

./bin/run-vnc
./bin/run-ghcid
firefox https://localhost:8080

Recover session from command line (after getting "Permission denied" error):

cabal run exe:butler -- run show-recovery $USERNAME

Use the electron client instead of firefox to forward your ssh-agent and enables Ctrl-T and Ctrl-N key code:

nix run --impure .#electron https://localhost:8080

Start the service with the pre-built container usage:

podman run -p 8080:8080 -v butler-data:/var/lib/butler --rm ghcr.io/butleros/haskell-butler:latest

Desktop workspace can be isolated using bubblewrap:

podman run --privileged --env BUTLER_ISOLATION=bwrap -p 8080:8080 -v butler-data:/var/lib/butler --rm ghcr.io/butleros/haskell-butler:latest

Contribute

Contributions and bug reports are welcome! To work on this project you need a Haskell toolchain: get-started.

Run the ./bin/run-tests script to validate a commit.

Run the test through ghcid with: ./bin/run-ghcid Main.main.

Setup binary cache with: nix run nixpkgs/release-22.11#cachix use haskell-platform.