Language Guide: Elixir

Overview

This guide will help you get started with an Elixir web application using Phoenix on CircleCI. If you’re in a rush, just copy the sample configuration below into a .circleci/config.yml in your project’s root directory and start building.

Otherwise, we recommend reading our walkthrough for a detailed explanation of our configuration.

Sample Configuration

version: 2
jobs:
  build:
    working_directory: ~/cci-demo-phoenix
    docker:
      - image: trenpixster/elixir:1.3.2
      - image: postgres:9.4.1
        environment:
          POSTGRES_USER: ubuntu
    steps:
      - checkout
      - run: mix deps.get
      - run: mix ecto.create
      - run: mix test

Get the Code

Coming soon…

Config Walkthrough

We always start with the version.

version: 2

Next, we have a jobs key. Each job represents a phase in your Build-Test-Deploy process. Our sample app only needs a build job, so everything else is going to live under that key.

In each job, we specify a working_directory. In this sample config, we’ll name it after the project in our home directory.

version: 2
jobs:
  build:
    working_directory: ~/cci-demo-phoenix

This path will be used as the default working directory for the rest of the job unless otherwise specified.

Directly beneath working_directory, we can specify container images for the build under a docker key.

version: 2
...
    docker:
      - image: trenpixster/elixir:1.3.2
      - image: postgres:9.4.1
        environment:
          POSTGRES_USER: ubuntu

We use 2 Docker images here: trenpixster/elixir:1.3.2 as the primary build image and postgres:9.4.1 as the database image.

Now we’ll add several steps within the build job.

We’ll do 4 things: checkout the codebase, install missing dependencies, create the storage for the repo, and finally run the tests:

...
    steps:
      - checkout
      - run: mix deps.get
      - run: mix ecto.create
      - run: mix test

Nice! You just set up CircleCI for a Phoenix app.

If you have any questions, head over to our community forum for support from us and other users.