Surat Pyari

Micro Services with Sinatra

Why to choose Sinatra?

Why Sinatra? That is another topic for blog. for me

  1. I am ruby developer and in my team I have many people with this skill.
  2. You can easily find a ruby developer and so this is maintainable as compare to other language like elixir, go
  3. It doesn’t come with heavy package like rails and so its perfect choice for micro service
  4. Performance over other ruby framework is much better. Sinatra is 3 times faster than Rails.

1. Create a new app with Bundler

Create a folder with your project name and add Gemfile.

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

ruby '2.4.2'

gem 'sinatra', require: 'sinatra'
gem "puma" # to start our server

Create config.ru so that it load bundler before it loads Sinatra app.

require 'rubygems'
require 'bundler'

Bundler.require
 
require './microservice_with_sinatra_app'
run MicroserviceWithSinatraApp

Now add a new file described in config.ru` i.e. microservice_with_sinatra_app.rb

require_relative 'env'

class MicroserviceWithSinatraApp < Sinatra::Base

  get '/' do
    'hello world'
  end
  
end

Yes we are missing environments! :). Add a file `env.rb`

require 'bundler/setup'

APP_ENV = ENV["RACK_ENV"] || "development"

Bundler.require :default, APP_ENV.to_sym

start server with following command

bundle exec rackup

Open http://localhost:9292/ and see you hello world app.

2. Configuration with PostgreSQL

This step is totally optional. If you need to do some database storage you may need this step.

Add following gems ..

gem "pg"    # for Postgres
gem "rake"  # so we can run Rake tasks
gem "sinatra-activerecord", require: 'sinatra/activerecord'    # for Active Record models

Modify config.ru as follow:

...
Bundler.require
require 'sinatra/activerecord'
require 'sinatra/activerecord/rake'
...

Create config/database.yml 

development:
  adapter: postgresql
  encoding: unicode
  database: database_name
  pool: 2
  username: your_username
  password: your_password

production:
  adapter: postgresql
  encoding: unicode
  pool: 5
  host: <%= ENV['DATABASE_HOST'] %>
  database: <%= ENV['DATABASE_NAME'] %>
  username: <%= ENV['DATABASE_USER'] %>
  password: <%= ENV['DATABASE_PASSWORD'] %>

Generate a new migration. 

rake db:create_migration NAME=create_table_name

and edit your migration according to your need just like rails migration.

Now you can add desired models and can work just like small rails app. Next will be integrating RabbitMQ and other stuff required to create a micro service. KEEP READING …

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