README.md

A (highly opinionated) Docker image for Haskell development

Note: The way this container setup is very opinionaed, you may want to check out an official dev containter for Haskell.

Table of Contents

• A (highly opinionated) Docker image for Haskell development
  • Visual Studio Code: DevContainer for Haskell
    • What is this
    • How to use this
    • How does it work
  • What's in the box
    • How to build locally

Visual Studio Code: DevContainer for Haskell

What is this

This is a DevContainer ^[1][2] environment for Visual Studio Code, allowing automatically installing the Haskell compiler (GHC), Stack, Cabal, HLS (Haskell Language Server), and the necessary Visual Studio Code extensions to set up a Haskell development environment with zero additional effort.

Note: For debugging support, please refer to Haskell GHCi Debugger Adapter Phoityne extension documentation.

How to use this

Follow the Getting Started instructions to configure your Visual Studio Code and Docker to use with DevContainers.

Place the .devcontainer directory in the root of your project, and the next time you load the project, Visual Studio Code will prompt to re-open the project in a container:

Note: building the container might take a few minutes until all dependencies have finished downloading and installing.

How does it work

Visual Studio Code supports Developing inside a Container - using a Docker image as a development environment. It automates the process of creating the container image, as well as installing additional required extensions into the editor.

Pressing Reopen in Container will perform the automated steps to launch the container, and set up the environment.

For more information and setup, read the official documentation: https://code.visualstudio.com/docs/remote/containers and https://code.visualstudio.com/docs/remote/containers-advanced

What's in the box

.devcontainer/Dockerfile DevContainer Docker image.

debian:bullseye as a base image.

Additional software installed:

• Glasgow Haskell Compiler (GHC) via ghcup.
• A Haskell LSP server HLS - (haskell-language-server).
• Stack.
• Cabal.
• Following Debian packages: apt-utils bash build-essential ca-certificates curl gcc git gnupg libffi-dev libffi7 libgmp-dev libgmp-dev libgmp10 libicu-dev libncurses-dev libncurses5 libnuma1 libnuma-dev libtinfo5 lsb-release make procps software-properties-common sudo wget xz-utils z3 zlib1g-dev.
• Following Haskell packages (via cabal): haskell-dap ghci-dap haskell-debug-adapter hlint apply-refact retrie stylish-haskell hoogle ormolu liquidhaskell.
• LLVM 12 via LLVM Automatic installation script.

NOTE: When changing GHC/HLS versions, please refer to the GHC/HLS compatibility table.

Following VSCode extensions are installed after container is started:

• Haskell extension.
• Haskell GHCi Debugger Adapter.
• Integrated Haskell Shell.
• Hoogle for VSCode.

The devcontainer.json has some additional configuration for VSCode, in particular, the required extensions that have to be installed, the name of the remote user (must match the one in the Dockerfile), and...⏎

... the following settings

{
    "files.exclude": {
      "**/*.olean": true,
      "**/.DS_Store": true,
      "**/.git": true,
      "**/.hg": true,
      "**/.svn": true,
      "**/CVS": true
    },
    "haskell.checkProject": true,
    "haskell.formattingProvider": "ormolu",
    "haskell.indentationRules.enabled": true,
    "haskell.liquidOn": true,
    "haskell.manageHLS": "GHCup",
    "haskell.maxCompletions": 40,
    "haskell.openDocumentationInHackage": false,
    "haskell.openSourceInHackage": false,
    "haskell.plugin.alternateNumberFormat.globalOn": true,
    "haskell.plugin.callHierarchy.globalOn": true,
    "haskell.plugin.changeTypeSignature.globalOn": true,
    "haskell.plugin.class.globalOn": true,
    "haskell.plugin.eval.config.diff": true,
    "haskell.plugin.eval.config.exception": true,
    "haskell.plugin.eval.globalOn": true,
    "haskell.plugin.ghcide-code-actions-bindings.globalOn": true,
    "haskell.plugin.ghcide-code-actions-fill-holes.globalOn": true,
    "haskell.plugin.ghcide-code-actions-imports-exports.globalOn": true,
    "haskell.plugin.ghcide-code-actions-type-signatures.globalOn": true,
    "haskell.plugin.ghcide-completions.config.autoExtendOn": true,
    "haskell.plugin.ghcide-completions.config.snippetsOn": true,
    "haskell.plugin.ghcide-completions.globalOn": true,
    "haskell.plugin.ghcide-hover-and-symbols.hoverOn": true,
    "haskell.plugin.ghcide-hover-and-symbols.symbolsOn": true,
    "haskell.plugin.ghcide-type-lenses.config.mode": "always",
    "haskell.plugin.ghcide-type-lenses.globalOn": true,
    "haskell.plugin.haddockComments.globalOn": true,
    "haskell.plugin.hlint.codeActionsOn": true,
    "haskell.plugin.hlint.config.flags": [],
    "haskell.plugin.hlint.diagnosticsOn": true,
    "haskell.plugin.importLens.codeActionsOn": true,
    "haskell.plugin.importLens.codeLensOn": true,
    "haskell.plugin.moduleName.globalOn": true,
    "haskell.plugin.pragmas.codeActionsOn": true,
    "haskell.plugin.pragmas.completionOn": true,
    "haskell.plugin.qualifyImportedNames.globalOn": true,
    "haskell.plugin.refineImports.codeActionsOn": true,
    "haskell.plugin.refineImports.codeLensOn": true,
    "haskell.plugin.refineImports.globalOn": true,
    "haskell.plugin.rename.config.crossModule": true,
    "haskell.plugin.rename.globalOn": true,
    "haskell.plugin.retrie.globalOn": true,
    "haskell.plugin.splice.globalOn": true,
    "haskell.plugin.tactic.config.max_use_ctor_actions": 5,
    "haskell.plugin.tactics.codeActionsOn": true,
    "haskell.plugin.tactics.codeLensOn": true,
    "haskell.plugin.tactics.config.auto_gas": 4,
    "haskell.plugin.tactics.config.hole_severity": "hint",
    "haskell.plugin.tactics.config.max_use_ctor_actions": 5,
    "haskell.plugin.tactics.config.proofstate_styling": true,
    "haskell.plugin.tactics.config.timeout_duration": 5,
    "haskell.plugin.tactics.globalOn": true,
    "haskell.plugin.tactics.hoverOn": true,
    "haskell.trace.client": "error",
    "haskell.trace.server": "off",
    "haskell.upgradeGHCup": true,
    "hoogle-vscode.useCabalDependencies": true
}

This was initially based on the DevContainer for HIE (Haskell IDE Engine) by Igal Tabachnik.

How to build locally

To build the image locally, just run docker build ./.devcontainer/ --file ./.devcontainer/Dockerfile --tag haskelldevenv:latest in the repository root.

You can override GHC version, Cabal version, Stack resolver and HLS version by specifying GHC_VERSION=..., CABAL_VERSION=..., STACK_RESOLVER=... and HLS_VERSION=... respectively as build args.

For example:

• docker build ./.devcontainer/ --file ./.devcontainer/Dockerfile --tag haskelldevenv:latest --build-arg GHC_VERSION=8.10.7
• docker build ./.devcontainer/ --file ./.devcontainer/Dockerfile --tag haskelldevenv:latest --build-arg STACK_RESOLVER=lts-18.13
• docker build ./.devcontainer/ --file ./.devcontainer/Dockerfile --tag haskelldevenv:latest --build-arg CABAL_VERSION=3.6.2.0
• docker build ./.devcontainer/ --file ./.devcontainer/Dockerfile --tag haskelldevenv:latest --build-arg HLS_VERSION=1.5.1
• docker build ./.devcontainer/ --file ./.devcontainer/Dockerfile --tag haskelldevenv:latest --build-arg GHC_VERSION=8.8.4 --build-arg STACK_RESOLVER=lts-18.13 --build-arg CABAL_VERSION=3.6.2.0 --build-arg HLS_VERSION=1.5.1

To run the image, just do docker run --rm -it haskelldevenv:latest.

Valid values for GHC_VERSION can be found here.