How to make an active job in ruby on rails to read json file then transfer data to database

Question

I'm newbie here. I have problem, I build a web use Ruby on Rails. I want to get data from json file and then insert into database. data in json file can be increased at any time. So I should have a background job to run in certain intervals. I have read in Ruby documentation, and it said that I can use Active Job. But I still confuse to do that. What should I do step by step to make it real? or you guys can give me example?

Thanks anyway.

Answer 1

You can use ActiveJob

Active Job Setup

The Active Job adapter must be set to :sidekiq or it will simply use the default :inline.

This can be done in config/application.rb like this:

For example:

class Application < Rails::Application
  # ...
  config.active_job.queue_adapter = :sidekiq
end

Next, generate Job:

rails generate job Example

Sample JSON Data:

{
    "title"  :    "Ruby In Rails",
    "url"    :    "http://rubyinrails.com",
    "posts"  :    {
                    "1":"strftime-time-format-in-ruby",
                    "2":"what-is-gemset"
                  }
}

Will creates /app/jobs/example_job.rb

class ExampleJob < ActiveJob::Base
  # Set the Queue as Default
  queue_as :default

  def perform(*args)
    # Perform Job
    require 'json'

    # Open JSON File
    root = Rails.root.to_s       
    file = File.read('#{root}/data.json')


    # Parse Data from File
    data_hash = JSON.parse(file)

    # Do the SAVING and validation HERE...
    test = Sample.new
    test.title = data_hash['title']
    ......
    test.save


  end
end

Usage, ex. in Controller:

ExampleJob.perform_later args

Documentations Here

Or if you prefer to USE CRONJOB for that function:

For example make a file named " save_json.rb " inside lib/tasks/ in your Rails Application.

Code:

namespace :save_json do
  desc "..."
  task :execute => :environment do
    require 'json'

    # Open JSON File
    root = Rails.root.to_s       
    file = File.read('#{root}/data.json')


    #Parse Data from File
    data_hash = JSON.parse(file) 

    #Getting DATA

    data_hash['title']
     => "Ruby In Rails"
    data_hash.keys
     => ["title", "url", "posts"]
    data_hash['posts']
     => { "1" => "strftime-time-format-in-ruby", "2" => "what-is-gemset" }

    # Do the SAVING and validation HERE...
    test = Sample.new
    test.title = data_hash['title']
    ......
    test.save

end

Set Background Job function in crontab .

vi /etc/crontab

Code: For example every minute ....

*/1 * * * * cd /my_rails_app && bundle exec rake save_json:execute