build git-crypt for alpine

[ghost]

Containerize git-crypt

Simple dockerfile that builds git-crypt for alpine linux and wraps it in a small container ~9MB.

Context

I recently started working with https://github.com/concourse/concourse and as a result needed a way to be able to decrypt and encrypt my repos without too much effort.

Problem Statement

Working with concourse introduced a restriction where every task is in a new container.
It simply made sense to create a base image that extended a small footprint ( like https://github.com/gliderlabs/docker-alpine ) and alpine does not contain an apk package for git-crypt. It was easy enough to build in-image and remove the utils leaving a alpine+git-crypt image.

Solution

Create an alpine image that has git-crypt already bundled.

Pending work

• Add to makefile target to build image
• Work with current checkout as compared to pulling from HEAD
• Pass version info via make

[spk]

Hi git-crypt is packaged on alpine https://pkgs.alpinelinux.org/package/edge/community/x86/git-crypt