nix-package-template

Experiment to attempt to build a Scala application using Nix as much as possible. Running nix build will create a jar and package it as a Docker compatible tar file. The only dependency to doing this should be installing Nix. SBT is being used to download the application dependencies, doing that with Nix would require a lot more dedication.

Instructions below on how to run this package locally. When creating a tag in Github it will publish this to GH packages so it can be downloaded like any other container.

Some parts of this reference Cachix which will need to be updated to point to an account you have control over, or could be commented out.

development environment

Start a nix shell with

nix develop -i

build and run locally

To run the full build

nix develop -i
> genericBuild

or as it runs in CI (make sure to delete all /target directories if running locally, and can still be flaky)

nix build --json
#  [{"drvPath":"/nix/store/34b4iqha5sjaj5dbbk3jw6k024dw02y5-docker-image-nix-package-template.tar.gz.drv","outputs":{"out":"/nix/store/dhmjfmlfp2pjsp2i0jkssa4kn2xqn6pm-docker-image-nix-package-template.tar.gz"}}]

OUT=$(nix build --json | jq -r ".[] | .outputs.out")

docker load -i $OUT
# Loaded image: nix-package-template:latest

docker run nix-package-template:latest

On push to a pull request branch or merge to master this will run in GH Actions pretty much as described here.

On tag it will also push to GH Packages.