Worked 2015-09-08 for Phoenix 1.0.1 on Dokku 0.3.25.
These instructions assume you've set up Dokku. If not, go find a tutorial for that part. My notes for setting it up on Digital Ocean.
Create a Dokku app:
$ ssh dokku apps:create my_app_name
Make it support multiple buildpacks:
$ ssh dokku config:set my_app_name BUILDPACK_URL=https://github.com/ddollar/heroku-buildpack-multi.git
List the two buildpacks you need:
$ echo "https://github.com/HashNuke/heroku-buildpack-elixir.git" >> .buildpacks
$ echo "https://github.com/gjaldon/heroku-buildpack-phoenix-static.git" >> .buildpacks
$ cat .buildpacks
https://github.com/HashNuke/heroku-buildpack-elixir.git
https://github.com/gjaldon/heroku-buildpack-phoenix-static.git
For Phoenix 1.1, you may need to configure the static buildpack to use node 5+:
echo node_version=5.3.0 > phoenix_static_buildpack.config
If you want to lock down the versions or Erlang and/or Elixir, you can configure the Elixir buildpack.
Get rid of a locale-related warning ("warning: the VM is running with native name encoding of latin1 which may cause Elixir to malfunction as it expects utf8. Please ensure your locale is set to UTF-8 (which can be verified by running "locale" in your shell)"):
$ ssh dokku config:set my_app_name LC_ALL=en_US.utf8
Put your SECRET_KEY_BASE in Dokku config:
# Change these values as appropriate…
$ ssh dokku config:set my_app_name SECRET_KEY_BASE=the_value_in_my_prod_secret_file
In config/prod.secret.exs, read from that config (replacing the old hard-coded value):
secret_key_base: System.get_env("SECRET_KEY_BASE")
Set the domain/host of your site in the same way:
# Change these values as appropriate…
$ ssh dokku config:set my_app_name HOSTNAME=my_hostname.example.com
In prod.exs, read from that config (replacing "example.com"):
url: [host: System.get_env("HOSTNAME"), port: 80]
If you're using a database, read that from config as well, like you did above.
# This varies depending on what you use for DBs in Dokku.
$ ssh dokku psql:create my_app_name
config :hello_phoenix, HelloPhoenix.Repo,
adapter: Ecto.Adapters.Postgres,
url: System.get_env("DATABASE_URL"),
pool_size: 20
In .gitignore, comment this out:
#/config/prod.secret.exs
Now your secret-less prod.secret.exs can be committed and deployed.
So, commit! Push to Dokku! Done:
git commit -am "All done"
git remote add dokku dokku@example.com:my_app_name
git push dokku