From building to deploying Ruby on Jets in docker-compose environment <Part 1>

Overview

Ruby on Jets is a Rails-like serverless framework. https://rubyonjets.com/docs/

It is assumed that you are using AWS Lambda.

It is very convenient to be able to manage Lambda settings with config/application.rb like Rails.

Since you can start puma locally like Rails with a single command, it is very easy to build an environment even though it is serverless.

From now on, I will write about building and deploying the development environment in the docker environment of Ruby On Jets.

This is Part 2.

Execution environment

docker 19.03.13

docker-compose 1.27.4

ruby 2.5.7

Ruby on Jets 2.0.6

PostgreSQL 11.6

Creating a local environment

Creating Dockerfile / docker-compose.yml / Gemfile

• Dockerfile

FROM ruby:2.5.7

RUN curl -sL https://deb.nodesource.com/setup_8.x | bash - &&\
    apt-get update -qq &&\
    apt-get install -y build-essential nodejs postgresql-client graphviz task-japanese fonts-ipafont fonts-noto-cjk &&\
    apt-get -y install rsync &&\
    apt-get -y install zip

ENV LANG ja_JP.UTF-8

ENV TZ=Asia/Tokyo

RUN curl -sL https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip -o awscliv2.zip | bash - &&\
    unzip awscliv2.zip &&\
    ./aws/install

WORKDIR /usr/src/app
COPY Gemfile .
COPY Gemfile.lock .
RUN bundle install

CMD ["/bin/sh"]

I'm using rsync and awscli. I'm sorry if there is excess or deficiency. ..

• docker-compose.yml

version: '3'
volumes:
  bundle:
  postgres:
services:
  app:
    build: .
    ports:
      - 3000:3000
    volumes:
      - bundle:/usr/local/bundle
      - .:/usr/src/app:delegated
      - ~/.aws:/root/.aws
    depends_on:
      - postgres
    links:
      - postgres
    stdin_open: true
    tty: true
    env_file:
      - .env.container
    command: /bin/sh -c "bundle exec jets server --host '0.0.0.0' --port '3000'"
  postgres:
    image: postgres:11.6-alpine
    ports:
      - 5432:5432
    volumes:
      - postgres:/var/lib/postgresql/data

Since you can start puma with jets server, it runs when the container starts.

The environment variable management file is explicitly named .env.container.

The reason is that I wanted to make a clear distinction between the environment variables in the docker container and the environment variables in the application.

Also, what was the demon here was where to have the aws credential.

This time I mounted the credential file with volume.

It seems that it is not recommended. .. In CI, I think there is no problem if the encrypted key is decrypted on the pipeline.

Please note that this method is based on the assumption that the deployment user's credentials are used for local ~/.aws.

What this means is that you will be deploying using the user information that already exists in ~/.aws, so you will be giving that user the IAM policy required for deployment.

If it is not convenient, create a new deployment user and mount the credential file in the app container.

app:
  volumes:
    - <Path with credentials>:/root/.aws

• Gemfile

For the time being, this is all you need.

source 'https://rubygems.org'
git_source(:github) do |repo| "https://github.com/#{repo}.git" end

gem 'jets'

Create an empty Gemfile.lock and .env.container.

$ touch Gemfile.lock
$ touch .env.container

Create a jets project

$ docker-compose build
$ docker-compose run --rm app jets new . --database=postgresql --mode=api

I hit the above command referring to the following.

https://rubyonjets.com/reference/jets-new/

https://rubyonjets.com/docs/new-modes/

This time we will create it in api mode.

You will be asked if you want to overwrite the Gemfile here.

Enter y. Please customize it later.

conflict  Gemfile
Overwrite /usr/src/app/Gemfile? (enter "h" for help) [Ynaqdhm]
#y press enter

Now that the Gemfile has been updated, do bundle install again.

$ docker-compose run --rm app bundle install

db creation

Describe the environment variables in .env.container. This time, we will describe the DB information.

DB_NAME=hoge
DB_HOST=fuga
DB_USER=hogehoge
DB_PASS=fugafuga
POSTGRES_HOST_AUTH_METHOD=trust

Execute db: create.

$ docker-compose run --rm app bundle exec jets db:create

Create a template with scaffold for the time being.

$ docker-compose run --rm app bundle exec jets g scaffold post title:string
This will be rejected in the future unless you explicitly pass the options `check_default_type: false` or call `allow_incompatible_default_type!` in your code
You can silence deprecations warning by setting the environment variable THOR_SILENCE_DEPRECATION.
      invoke  active_record
      create    db/migrate/20200927064200_create_posts.rb
      create    app/models/post.rb
      invoke  resource_route
       route    resources :posts
Deprecation warning: Expected string default value for '--test-framework'; got false (boolean).
This will be rejected in the future unless you explicitly pass the options `check_default_type: false` or call `allow_incompatible_default_type!` in your code
You can silence deprecations warning by setting the environment variable THOR_SILENCE_DEPRECATION.
      invoke  scaffold_controller
      create    app/controllers/posts_controller.rb

Execute db: migrate.

$ docker-compose run --rm app bundle exec jets db:migrate

Try launching the container

$ docker-compose up

This will run the jets server and bring up the local server.

If you can check the browser at http://0.0.0.0:3000, it's OK.

Summary

This time, we were able to confirm that the application server started up locally, creating an environment where we could develop.

In the second part, I would like to write about how to create a stag, prod environment, etc. from the IAM policy for deployment.