Scheduling tasks in Rails with Cron jobs & using the “Whenever” Gem.

By: Piyush Duragkar Category: Ruby on Rails Technologies: Ruby on Rails

What is a Cron job?

A job scheduler, cron lets the user execute recurring tasks at a fixed time interval. Cron jobs can run in a background process.

For eg: every minute, hour, day, or year.

Understanding the use of the ‘whenever’ gem?

The “Whenever” gem is used to add and schedule a task to the crontab file. It is a Ruby gem that gives a clear syntax for writing and deploying cron jobs.

Steps to generating Excel sheet every 12 hours.

Step 1: Add the gem ‘whenever’ to your gemfile.

Step 2: To install ‘whenever’, run the command “gem install whenever”

Step 3: Run “bundle install”

Step 4: Run “wheneverize”.

This command will generate “schedule.rb” in config.

Step 5: Create the Rake task — This will generate inside ”lib/asstes/tasks”

syntax: rails g task <namespace> <taskname>

for eg: rails g task compositions generate_excel g

Step 6: Run the task

syntax: rake <namespace>:<taskname>

for example: rake compositions:generated_excel

Step 7: Copy the task in the schedule.rb file

Step 8: The user can store the generated file in a specific folder of the application.

Step 9: Update the crontab file according to the environment.

whenever — update-crontab — set environment=’development’.

Step 10: Run “rails s”

Conclusion:

A time-based scheduling utility, Cron jobs are used to execute commands. They are used to manage tasks in Rails. The user can use this command whenever a task is to be completed automatically and at times when the user does not have the time to enter a command manually. The user can also use it for their daily backup.

Originally published at https://www.cryptextechnologies.com.