ruby-clock

ruby-clock is a job scheduler, known by heroku as a clock process. In many cases it can replace the use of cron.

This gem is very small with very few lines of code. For all its scheduling capabilities, it relies on the venerable rufus-scheduler. rufus-scheduler does not aim to be a standalone process or a cron replacement, ruby-clock does.

Jobs are all run in their own parallel threads within the same process.

The clock process will respond to signals INT (^c at the command line) and TERM (signal sent by environments such as Heroku and other PaaS's when shutting down). In both cases, the clock will stop running jobs and give existing jobs 29 seconds to stop before killing them.

Installation

Add these lines to your application's Gemfile:

gem 'ruby-clock'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install ruby-clock

Usage

Create a file named Clockfile. This will hold your job definitions. The DSL and capabilities are the same as those of rufus-scheduler. Read the rufus-scheduler documentation to see what you can do.

schedule.every('5 minutes') do
  UserDataReports.generate
end

# do something every day, five minutes after midnight
schedule.cron '5 0 * * *' do
  DailyActivitySummary.generate_and_send
end

To start your clock process:

bundle exec clock

Rails

Install the clock binstub and commit to your repo.

bundle binstubs ruby-clock

To run your clock process in your app's environment:

bundle exec rails runner bin/clock

Non-Rails

Require your app's code at the top of Clockfile:

require_relative './lib/app.rb'
schedule.every('5 minutes') do
...

Heroku and other PaaS's

Add this line to your Procfile

clock: bundle exec rails runner bin/clock

More Config and Capabilities

Error Handling

You can catch and report errors raised in your jobs by defining an error catcher at the top of your Clockfile like this:

def schedule.on_error(job, error)
  ErrorReporter.track_exception(error)
end

Callbacks

You can define before, after, and around callbacks which will run for all jobs. Read the rufus-scheduler documentation to learn how to do this. Where the documentation references s, you should use schedule.

other rufus-scheduler Options

All rufus-scheduler options are set to defaults. The schedule variable available in your Clockfile is an instance of Rufus::Scheduler, so anything you can do on this instance, you can do in your Clockfile.

Perhaps in the future ruby-clock will add some easier specific configuration capabilities for some things. Let me know if you have a request!

License

The gem is available as open source under the terms of the MIT License.