View Source Deploy to Fly.io

Once you have a Beacon site up and running locally, you can deploy it on Fly.io by following this guide.

Fly.io CLI

First, install the fly cli tool, as described at Install flyctl. You'll need it to deploy your site.

Sign in or sign up

Don't have an account yet? Sign up by running:

fly auth signup

Or sign in to your existing account:

fly auth login

Dockerfile

Fly applications run in containers. Let's generate a Dockerfile and make a couple of changes:

Run:

mix phx.gen.release --docker

Edit the generated Dockerfile and make some changes:

1. Install npm by adding it to the apt-get install list

It should look like this:

RUN apt-get update -y && apt-get install -y build-essential git npm \

2. Add the following code before RUN mix assets.deploy:

RUN npm install --prefix assets

Copy files into the release

Open the file mix.exs and locate the project/0 function. Add a new :releases config that contains a custom step to copy Beacon files:

releases: [
  my_app: [
    steps: [:assemble, &copy_beacon_files/1]
  ]
]

Replace my_app with your actual app name. The whole function will look similar to this:

def project do
  [
    app: :my_app,
    version: "0.1.0",
    elixir: "~> 1.14",
    elixirc_paths: elixirc_paths(Mix.env()),
    start_permanent: Mix.env() == :prod,
    consolidate_protocols: Mix.env() != :dev,
    aliases: aliases(),
    deps: deps(),
    releases: [
      my_app: [
        steps: [:assemble, &copy_beacon_files/1]
      ]
    ]
  ]
end

Now create a new function copy_beacon_files/1 at any place in the mix.exs file:

defp copy_beacon_files(%{path: path} = release) do
  case Path.wildcard("_build/tailwind-*") do
    [] ->
      raise """
      tailwind-cli not found

      Execute the following command to install it before proceeding:

          mix tailwind.install

      """

    tailwind_bin_path ->
      build_path = Path.join([path, "bin", "_build"])
      File.mkdir_p!(build_path)

      for file <- tailwind_bin_path do
        File.cp!(file, Path.join(build_path, Path.basename(file)))
      end
  end

  File.cp!(Path.join(["assets", "css", "app.css"]), Path.join(path, "app.css"))

  release
end

Essentially this function will copy the tailwind-cli binary and the app.css files into the release. The tailwind-cli binary is required but app.css is only used if you actually reuse it on your sites.

See https://hexdocs.pm/mix/Mix.Tasks.Release.html for more info about releases configuration.

Launch

With your account in place and all files updated, it's time to launch your application. Run:

fly launch

When asked if you would like to set up a PostgreSQL database, answer YES and choose the most appropriate configuration for your site.

When asked if you would like to deploy, answer YES or run fly deploy afterward when you're ready to deploy.

Deploy

Beacon is designed to minimize deployments as much as possible, but eventually, you can trigger new deployments by running:

fly deploy

Open

Finally, if you followed the guides to set up your site, run the following command to see it live:

fly open /

If you have created a custom page, simply replace / in the above command to match its prefix.

More commands

You can find all available commands in the Fly.io docs and also find more tips on the official Phoenix Deploying on Fly.io guide.

Troubleshooting

The default config file fly.toml created by fly launch defines min_machines_running = 0 so Fly will auto-stop machines that receive no traffic for a period of time. You might want to change this value to 1 otherwise it will look like your app is not working, when in fact it's just Fly proxy doing its job.