Readme

A simple tool that allows one to quickly bundle all the transitive dependencies of a set of haskell package using cabal so that they could be deployed offline to another computer.

The bundle is in the form of a tarball with a companion bash deploy script that will automatically extract the tarball to the proper location.

Prerequisites

• An installation of ghc with cabal-install
• bash which should be available on most systems. On windows, you can use msys2 or even git for windows.

Creating the bundle

First, make sure the computer that will be used to create the bundle runs on the same OS and is using the same version of ghc and haskell platform (if applicable) as the target computer.

git clone http://url/to/cabal_offline_install_bundler
cd cabal_offline_install_bundler
./create_hs_pkgs_tarball.sh first-hs-pkg second-hs-pkg

The bundle should have been created as a haskell_packages directory in the current working directory containing the following files:

• packages.tar.gz

  The actual bundle of haskell packages. Include both first-hs-pkg and second-hs-pkg but also all their transitive dependencies. This is litterally a copy of the content that can be found under ~/.cabal/packages.

• deploy_packages.sh

  The deployment script you should run on the target machine to install the bundled haskell packages.

Deploying the bundle

Transfer the bundle on the target computer (which most likely does not have any internet access).

cd /my/path/on/the/target/computer/to/haskell_packages
./deploy_packages.sh
cabal install --offline first-hs-pkg second-hs-pkg 

If everything went well, the packages should have been installed successfully even though there is no internet connection on this computer.

Tips and trick

• On linux, in order to play safe with your global cabal package set, you can specify an alternate home directory like so: export HOME=./path/to/my/alt/home/dir. A .cabal will be created there. Note that even without this, the scripts take a backup of all your cabal dot files and restore them afterward.

• If using nix, you most likely have existing haskell package installed. Because of nix's way of doing things, removing the cabal dot files temporarily as does this script won't be enough to fool the cabal fetch command used internally into thinking that no haskell packages are installed. This is why the shell.nix environement is provided. Simply enter this environement using nix-shell --pure before calling ./create_hs_pkgs_tarball.sh and the tool should work as expected.