Elixir/Phoenix API backing the Elm web-client for Participate!. More about the project on the web-client README

Setup

Prerequisites

• Elixir (tested with Elixir version 1.4.1)
• PostgreSQL (tested with PostgreSQL 9.6.1)

Build

Get dependencies and compile:

$ mix deps.get
$ mix compile

Create a database participate_api_dev and insert initial data:

$ mix ecto.setup

To update an existing database with new migrations:

$ mix ecto.migrate

Start the API server:

$ mix phoenix.server

Running tests

When running the suite for the first time, run it twice: the first time you'll get an error about the test db not being created yet, the second time it'll run fine - the db will have been created by then.

$ mix espec

Espec is a BDD test framework very much like ruby's Rspec.

Deploy to Heroku

The API can be easily deployed to Heroku. Their free plan is sufficient for developing and demonstration.

The Phoenix Framework documentation provides a good overview of how to deploy an Elixir app.

Quick walkthrough:

• We assume that you have the Heroku CLI tool installed.

• Login in to a Heroku account:

  $ heroku login
  

• Create Heroku app:

  $ heroku create participate-api --region eu
  

  App names must be unique in the Heroku cloud. Choose your own name. Or omit the name in the command to get a random name.
  Possible regions are currently us and eu.
  This command will also add a git remote called heroku to your git repository configuration. We will push to it later.

• Add the buildpack for Elixir apps:

  $ heroku buildpacks:add https://github.com/HashNuke/heroku-buildpack-elixir.git
  

• Add a PostgreSQL database as an add-on to the app:

  $ heroku addons:create heroku-postgresql:hobby-dev
  

• Set the number of concurrent connections that the app is allowed to make to the database:

  $ heroku config:set POOL_SIZE=8
  

  A free hobby-dev Heroku Postgres allows 20 connections at maximum for all running dynos accessing it.

• Generate a Phoenix secret and set a configuration variable to it:

  $ heroku config:set SECRET_KEY_BASE=$(mix phoenix.gen.secret)
  

  This command uses bash syntax. For other systems split it in two commands. Insert the generated key into the second command:

  $ mix phoenix.gen.secret
  $ heroku config:set SECRET_KEY_BASE=...
  

• Review the settings in elixir_buildpack.config and config/prod.exs.
  Commit any changes you may have made.

• Deploy the app by pushing the repo to Heroku:

  $ git push heroku master
  

  Heroku will build the app only when pushing to branch master. If you are pushing from a different local branch use:

  $ git push heroku my-local-branch:master
  

  Pushing will start the build process, mainly compiling the Elixir code. Watch out for possible error messages.

• Populate the database with initial content:

  $ heroku run "MIX_ENV=prod POOL_SIZE=2 mix ecto.migrate"
  

• The API should be up and running at https://participate-api.herokuapp.com
  (Replace participate-api with you own app name). As a quick check run:

  $ heroku open
  

  This should display something like {"errors":{"detail":"Page not found"}} in your browser. (It's an error because we have currently no endpoint served at /.)

• To view log messages:

  $ heroku logs --tail
  

• Direct database access:

  • Show database credentials:

    $ heroku pg:credentials
    

  • You can use pgAdmin to access the database with the given credentials.

  • For managing backups see Heroku docs.

Want to get involved?

We'll pair with you so you can get up to speed quickly, and we pair on features as well.

Shoot us an email, we'll add you to our Slack channel to join the discussion and talk about next steps.

Please check out the contributing guide and our code of conduct

---

Participate was inspired by LiquidFeedback, and the book published by its authors: Principles of Liquid Feedback