The finished code for this example is available on GitHub.
Create a new Phoenix app in the terminal. We don't need a database for this example, so we're passing the
--no-ecto flag to
# install phx.new; feel free to change 1.4.9 to a different version $ mix archive.install hex phx_new 1.4.9 $ mix phx.new phoenix_hello --no-ecto # also fetch and install dependencies $ cd phoenix_hello
Create runtime configuration needed for Mix releases.
use Mix.Configin your new
- Uncomment the following line in
config :phoenix_hello, PhoenixHelloWeb.Endpoint, server: true # uncomment me!
- Finally, update
config/prod.exsto delete the line
import_config "prod.secret.exs"at the bottom.
We need to run a series of commands to build our app on every push to our Git repo, and we can accomplish this with a build script. Create a script called
build.sh at the root of your repo:
#!/usr/bin/env bash # Initial setup mix deps.get --only prod MIX_ENV=prod mix compile # Compile assets npm install --prefix ./assets npm run deploy --prefix ./assets mix phx.digest # Remove the existing release directory and build the release rm -rf "_build" MIX_ENV=prod mix release
Make sure the script is executable before checking it into Git:
$ chmod a+x build.sh
config/prod.exs to change the lines below.
config :phoenix_hello, PhoenixHelloWeb.Endpoint, url: [host: "example.com", port: 80], cache_static_manifest: "priv/static/cache_manifest.json"
config :phoenix_hello, PhoenixHelloWeb.Endpoint, url: [host: System.get_env("RENDER_EXTERNAL_HOSTNAME") || "localhost", port: 80], cache_static_manifest: "priv/static/cache_manifest.json",
If you add a custom domain to your Render app, don't forget to change the host to your new domain.
Compile your release locally by running
./build.sh. The output should look like this:
* assembling phoenix_hello-0.1.0 on MIX_ENV=prod * using config/releases.exs to configure the release at runtime * skipping elixir.bat for windows (bin/elixir.bat not found in the Elixir installation) * skipping iex.bat for windows (bin/iex.bat not found in the Elixir installation) Release created at _build/prod/rel/phoenix_hello! # To start your system _build/prod/rel/phoenix_hello/bin/phoenix_hello start Once the release is running: # To connect to it remotely _build/prod/rel/phoenix_hello/bin/phoenix_hello remote # To stop it gracefully (you may also send SIGINT/SIGTERM) _build/prod/rel/phoenix_hello/bin/phoenix_hello stop To list all commands: _build/prod/rel/phoenix_hello/bin/phoenix_hello
Test your release by running the following command and navigating to http://localhost:4000.
SECRET_KEY_BASE=`mix phx.gen.secret` _build/prod/rel/phoenix_hello/bin/phoenix_hello start
If everything looks good, push your changes to your repo. You can now deploy your app in production! 🎉
Create a new Web Service on Render, and give Render permission to access your Phoenix repo.
Use the following values during creation:
Field Value Environment
Under the Advanced section, add the following environment variables:
A sufficiently strong secret. Generate it locally by running
That's it! Your Phoenix web service built with Mix releases will be live on your Render URL as soon as the build finishes. Going forward, every push to your GitHub repo will automatically update and deploy your app with zero downtime. 💯