2020.05_elixir

School of Elixir 2020

Contact

Rafał Słota: rafal.slota@gmail.com

Useful links

• “Pointing Poker” - https://www.pointingpoker.com/
• Elixir - https://elixir-lang.org/install.html
• Phoenix - https://hexdocs.pm/phoenix/installation.html
• LiveView - https://hexdocs.pm/phoenix_live_view/installation.html
• Docker - https://docs.docker.com/get-docker/
• Bootstrap - https://getbootstrap.com/docs/4.0/components

1. Environment

1.1. Hex

mix local.hex

1.2. Phoenix

mix archive.install hex phx_new 1.5.1

2. Project preparation

2.1. Project init && dependencies

mix phx.new pointing_poker --live
cd pointing_poker
npm install bootstrap jquery popper.js --prefix assets
npm install sass-loader node-sass webpack --prefix assets

npm install --prefix assets

2.2. Database setup

Remove PointingPoker.Repo child from PointingPoker.Application

2.3. Enabling Bootstrap

In assets/js/app.js add:

import "bootstrap"

In assets/css/app.scss replace:

@import "./phoenix.css";

with:

@import "~bootstrap/scss/bootstrap";

2.4. Starting project

mix phx.server

Built in Dashboard: http://localhost:4000/dashboard

3. Project deployment

3.1. Setting up the release

We can prepare the release by:

# Generate release boot scripts
mix release.init

# Initial setup
mix deps.get --only prod
MIX_ENV=prod mix compile

# Install / update  JavaScript dependencies
npm install --prefix ./assets

# Compile assets
npm run deploy --prefix ./assets
mix phx.digest

Next, we need to create config/releases.exs file as primary release configuration file.

3.2. Running a release

After we do that, we can generate the release with:

MIX_ENV=prod mix release

We can run it with:

export SECRET_KEY_BASE=`mix phx.gen.secret`
_build/prod/rel/pointing_poker/bin/pointing_poker start

3.3. Building docker image

Place Dockerfile that you can find next to this README.md in you project's root.

docker build . -t pointing_poker:latest

We can try to run the container by:

docker run -e SECRET_KEY_BASE=`mix phx.gen.secret` -p 8080:4000 -it pointing_poker:latest

3.4. docker-compose.yml

3.5. Using distributed registry

Add the following to project dependencies:

{:syn, "~> 2.1"}

Next, we need to replace Registry with :syn.

3.6. Adding auto-discovery

Add the following to project dependencies:

{:libcluster, "~> 3.2"}

Add to Application supervisor:

{Cluster.Supervisor, [cluster_config(), [name: PointingPoker.ClusterSupervisor]]}


# With the following function definition:
defp cluster_config() do
    [
      gossip: [
        strategy: Cluster.Strategy.Gossip,
        config: [
          port: 45892,
          if_addr: "0.0.0.0",
          multicast_addr: "230.1.1.251",
          multicast_ttl: 1
        ]
      ]
    ]
  end

3.7. Configure ERTS to use deterministic ports

In rel/vm.args.eex:

-kernel inet_dist_listen_min 4370
-kernel inet_dist_listen_max 4370

In rel/env.sh/eex:

export RELEASE_DISTRIBUTION=name
export RELEASE_NODE=<%= @release.name %>@`hostname -i`