What Packages are Available for My Gigalixir App?

Gigalixir’s stacks are based on Heroku’s stacks, so anything you find here, you can find on Gigalixir. https://devcenter.heroku.com/articles/stack-packages#installed-ubuntu-packages

To find what stack you are on, run gigalixir apps:info or gigalixir ps. If you are on gigalixir-18, check the heroku-18 column. This is the same for all other stacks.

You can also explore and verify by SSH’ing into your container. For example:

gigalixir ps:ssh
convert --help

How do I Install Extra Binaries I Need for my App?

The process is different if you are using Elixir Releases or Mix.

We recommend switching to Mix mode as it’s much easier.

To switch to mix mode, see How Do I Switch to Mix Mode?.

In mix mode, all you have to do is add the relevant, buildpack to your .buildpacks file that is likely located at the top.

Also, make sure you also have the required Elixir, Phoenix, and mix buildpacks. For example, if you need Rust installed, your .buildpacks file might look like:

https://github.com/emk/heroku-buildpack-rust
https://github.com/gigalixir/gigalixir-buildpack-elixir
https://github.com/gigalixir/gigalixir-buildpack-phoenix-static
https://github.com/gigalixir/gigalixir-buildpack-mix.git

For Rust specifically, also be sure to run echo "RUST_SKIP_BUILD=1" > RustConfig since you just need the Rust binaries, and don’t want to build a Rust project.

In Mix mode, the entire build folder is packed up and shipped to your run container which means it will pack up the extra binaries you’ve installed and any .profile.d scripts needed to make them available.

Voila, that’s it!

If you are using Elixir releases, you also need to manually figure out which folders and files you need to be packed into your release tarball and copy them over using an extra "step". See https://hexdocs.pm/mix/Mix.Tasks.Release.html#module-steps

How Do I Use a Private Git Dependency?

If you want to use a private git repository as a dependency in mix.exs, our recommended approach is to use the netrc buildpack found at https://github.com/timshadel/heroku-buildpack-github-netrc

To use the buildpack, insert it in your .buildpacks file above the Elixir and Phoenix buildpacks. For example, if you are using Elixir Releases, your .buildpacks file will look like:

https://github.com/timshadel/heroku-buildpack-github-netrc.git
https://github.com/gigalixir/gigalixir-buildpack-elixir
https://github.com/gigalixir/gigalixir-buildpack-phoenix-static
https://github.com/gigalixir/gigalixir-buildpack-releases.git

Next, create a personal access token by following https://help.github.com/articles/creating-a-personal-access-token-for-the-command-line/

Just make sure you give the token "repo" access so that it can access your private repository.

Add your personal access token as a config var by running:

gigalixir config:set -a $APP_NAME GITHUB_AUTH_TOKEN="$GITHUB_TOKEN"

The last step is to add the dependency to your mix.exs file. Add it as you would any other git dependency, but be sure you use the HTTPS url and not the SSH url. For example:

{:foo, git: "https://github.com/jesseshieh/foo.git", override: true}

That should be it.

Alternatively, you could also put your Github username and personal access token directly into the git url, but it’s generally not a good idea to check in secrets to source control.

You could use System.get_env interpolated inside the git url, but then you run the risk of the secrets getting saved to mix.lock.

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