Simple Deployment of Phoenix / Elixir

Exrm releases seem extremely stable, but have some caveats:

• Require build environment to be very similar to deployment
• Require extra maintenance to ensure the correct application components are loaded by Erlang
• Requires a custom script to scp the release to the server

With these points in mind I decided to experiment with using a familiar Capistrano based workflow. Something along the lines of:

Capistrano deploys code -> Builds on server -> Upstart handles launch and keep-alive

Sadly however this didn't seem practical when it comes to Exrm's upgrade and downgrade. Instead I ended up creating a custom shell script.

It handles:

• Uploading all code to the remote server
• Compiling an Exrm release, the current version is detected from mix.exs
• Move release to app directory
• Run hot upgrade with Exrm
• Runs migrations on server

The script below is targeted to a project which uses Webpack in an app directory. If your project uses Brunch some minor modification may be necessary.

Create a file called exdeploy in the root of your project containing the code from the Gist at the end of this article.

Dont forget to chmod +x ./exdeploy to make it executable.

# Upload and compile current version onto the server
./exdeploy deploy

# Run migrations
./exdeploy migrate

# Restart (could be used after overwriting a version to relaunch)
./exdeploy restart

# Upgrade to the latest version
./exdeploy upgrade

You will need to customize the first few variables to include your app's name and server details etc.