CardanoSolutions / devx

The Developer Experience Shell - This repo contains a nix develop shell for haskell. Its primary purpose is to help get a development shell for haskell quickly and across multiple operating systems (and architectures).

The Developer Experience Shell

This repo contains a nix develop shell for haskell. Its primary purpose is to help get a development shell for haskell quickly and across multiple operating systems (and architectures).

It requires nix to be installed.

Once you have nix installed you can check that everything is working correctly:

• Make sure to add experimental-features = nix-command flakes and accept-flake-config = true lines to $XDG_CONFIG_HOME/nix/nix.conf file ;
• Make sure your $USER is trusted nix show-config | grep trusted-users, otherwise add it to /etc/nix/nix.conf and restart nix-daemon ;
• Make sure the nix-daemon is running using systemctl status nix-daemon (if your OS is systemd-based).

Once you have nix, (linux, macOS, windows WSL) you can use

nix develop github:input-output-hk/devx#ghc96 --no-write-lock-file --refresh

to obtain a haskell evelopment shell for GHC 8.10.7 including cabal-install, as well as hls and hlint. If you are on macOS on an apple silicon chip (M1, M2, ...), and want to switch between Intel (x86_64) and Apple Silicon (aarch64), you can do this by simply passing the corresponding --system argument:

nix develop github:input-output-hk/devx#ghc810 --no-write-lock-file --refresh --system x86_64-darwin

or

nix develop github:input-output-hk/devx#ghc810 --no-write-lock-file --refresh --system aarch64-darwin

direnv integration

If you use direnv, you can integrate this shell by creating an .envrc file with the following content:

# https://github.com/nix-community/nix-direnv A fast, persistent use_nix/use_flake implementation for direnv:
if ! has nix_direnv_version || ! nix_direnv_version 2.3.0; then
  source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/2.3.0/direnvrc" "sha256-Dmd+j63L84wuzgyjITIfSxSD57Tx7v51DMxVZOsiUD8="
fi
# https://github.com/input-output-hk/devx Slightly opinionated shared GitHub Action for Cardano-Haskell projects 
use flake "github:input-output-hk/devx#ghc810-iog"

Refer to direnv and devx guide for more information.

VSCode DevContainer / GitHub CodeSpace support

To make this developer shell available in VSCode DevContainer or GitHub CodeSpace, simply add a file named .devcontainer/devcontainer.json with the following content:

{
   "image":"ghcr.io/input-output-hk/devx-devcontainer:ghc810-iog",
   "customizations":{
      "vscode":{
         "extensions":[
            "haskell.haskell"
         ],
         "settings":{
            "haskell.manageHLS":"PATH"
         }
      }
   }
}

This configuration will work immediately in GitHub CodeSpace! For local VSCode DevContainer, you need Docker and the VSCode extension. For guidance on this, you can follow the Microsoft tutorial.

It's also advise to enable GitHub CodeSpace prebuilds in your repository settings, follow the instructions provided in the GitHub documentation. This will significantly enhance your development experience by reducing the setup time when opening a new CodeSpace.

List of images available: ghc810-iog, ghc96-iog, ghc810-js-iog, ghc96-js-iog, ghc810-windows-iog, ghc96-windows-iog

Compilers and Flavours

There are multiple compilers available, and usually the latest for each series from 8.10 to 9.6 (a slight delay between the official release announcement and the compiler showing up in the devx shell is expected due to integration work necessary). The current available ones are: ghc810, ghc90, ghc92,ghc94, and ghc96 (these are the same ones as in haskell.nix and may contain patches for defects in the official releases).

Flavours

There are various flavours available as suffixes to the compiler names (e.g. #ghc810-minimal-iog).

Flavour	Description	Example	Included
empty	General Haskell Dev	#ghc810	ghc, cabal-install, hls, hlint
-iog	IOG Haskell Dev	#ghc810	adds sodium-vrf, blst, secp256k1, R, postgresql
-minimal	Only GHC, and Cabal	#ghc810-minimal	drops hls, hlint
-static	Building static binaries	#ghc810-static	static haskell cross compiler
-js	JavaScript Cross Compiler	#ghc810-js	javascript haskell cross compiler
-windows	Windows Cross Compiler	#ghc810-windows	windows haskell cross compiler

these can then be comined following this schema:

#ghc<ver>[-js|-windows|-static][-minimal][-iog]

For example

nix develop github:input-output-hk/devx#ghc810-windows-minimal-iog --no-write-lock-file --refresh

would provide a development shell with a windows cross compiler as well as cabal, and the IOG specific libraries, but no Haskell Language Server (hls), and no HLint.

A full list of all available devShells can be see with:

nix flake show github:input-output-hk/devx

Note

For commercial support, please don't hesitate to reach out at [e-mail]