Deploying a Phoenix App

Phoenix is a modern web framework for Elixir, designed for building scalable, high-performance web applications. It features real-time capabilities, a productive developer experience, and leverages the power of the Erlang VM for fault-tolerance and concurrency.

This guide explains how to deploy a Phoenix application to Klutch.sh, both with and without a Dockerfile. It also covers installation and provides sample code to get started.

Prerequisites

• Elixir & Erlang installed (Install guide)
• Phoenix installed
• Git and GitHub account
• Klutch.sh account

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Getting Started: Install Phoenix

1. Install Phoenix:

   mix archive.install hex phx_new

2. Create a new Phoenix app:

   mix phx.new my-phoenix-app --no-ecto
   cd my-phoenix-app

3. Start the development server:

   mix phx.server

   Your app should be running at http://localhost:4000.

Sample Code (lib/my_phoenix_app_web/controllers/page_controller.ex)

Add a simple controller to your Phoenix project:

defmodule MyPhoenixAppWeb.PageController do
  use MyPhoenixAppWeb, :controller

  def index(conn, _params) do
    text(conn, "Hello from Phoenix on Klutch.sh!")
  end
end

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Deploying Without a Dockerfile

1. Push your Phoenix app to a GitHub repository.
2. Log in to Klutch.sh.
3. Create a new project and give it a name.
4. Create a new app:
   • Select your Phoenix GitHub repository and branch
   • Set the port to route traffic (usually 4000 for Phoenix)
   • Choose region, compute, number of instances, and add any environment variables
5. Add a start command in your app settings:

   mix phx.server

6. Make sure your app listens on the port provided by Klutch.sh via the PORT environment variable. In config/runtime.exs:

   port = String.to_integer(System.get_env("PORT") || "4000")
   config :my_phoenix_app, MyPhoenixAppWeb.Endpoint, http: [port: port]

7. Click “Create” to deploy. Klutch.sh will build and deploy your app automatically.

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Deploying With a Dockerfile

1. Add a Dockerfile to your project root. Example:

   # Use official Elixir image for build
   FROM elixir:1.16-alpine AS builder
   WORKDIR /app
   RUN apk add --no-cache build-base
   COPY . .
   RUN mix deps.get && mix assets.deploy && mix release
   
   # Use minimal image for running
   FROM alpine:latest
   WORKDIR /app
   RUN apk add --no-cache libstdc++ ncurses-libs openssl
   COPY --from=builder /app/_build/dev/rel/my_phoenix_app .
   
   # Expose port (match your Phoenix app)
   EXPOSE 4000
   
   # Start the app
   CMD ["bin/my_phoenix_app", "start"]

2. Push your code (with Dockerfile) to GitHub.
3. In Klutch.sh, follow the same steps to create a project and app, but select the Dockerfile option when prompted.
4. Set the service details and environment variables as needed.
5. Click “Create” to deploy. Klutch.sh will build your Docker image and deploy your app.

Note: Your Phoenix app should always listen on the PORT environment variable as shown above.

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Resources

• Klutch.sh Documentation
• Phoenix Documentation

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Deploying to Klutch.sh is simple and flexible. Choose the method that best fits your workflow and project requirements.