Schedule is a Crystal shard that provides a clear DSL to write periodic or scheduled tasks. It has the ability to stop or retry the job whenever is necessary, with proper ways to handle exceptions. See usage examples in examples folder.
Add this to your application's shard.yml
:
dependencies:
schedule:
github: hugoabonizio/schedule.cr
This blog post describes the basic usage of Schedule.
require "schedule"
# Print "Hello!" each 2 seconds
Schedule.every(2.seconds) do
puts "Hello!"
end
# Set a default exception handler
Schedule.exception_handler do |ex|
puts "Exception recued! #{ex.message}"
end
# Stop or retry a task
Schedule.every(100.milliseconds) do
begin
count += computed_value
rescue
Schedule.retry
end
Schedule.stop if count >= MAX_VALUE
end
# Execute a task after X interval
Schedule.after(2.seconds) do
puts "Hi!"
end
# Schedule task every day at a particular time
Schedule.every(:day, "16:00:00") do
puts "Good Afternoon!"
end
# Schedule task to run multiple time every day
Schedule.every(:day, ["16:00:00", "18:00:00"]) do
puts "Greetings!"
end
# Schedule task to run a particular time at particular day of the week
Schedule.every(:sunday, "16:00:00") do
puts "House Keeping"
end
# Schedule task to run multiple time on a given day
Schedule.every(:sunday, ["16:00:00", "18:00:00"] do
puts "Greetings!"
end
runner = Schedule::Runner.new
runner.every(100.milliseconds) do
Schedule.stop if condition
end
runner.exception_handler do |ex|
puts ex.message
end
A task can be stopped or retried using Schedule.stop
and Schedule.retry
respectively.
Schedule.every(10.seconds) do
result = try_to_update
Schedule.retry if result == -1
Schedule.stop if updates >= MAX_COUNT
end
You can use the Schedule.exception_handler do ... end
form to set an exception handler or directly pass a proc to the Schedule.exception_handler
class property.
handler = ->(ex : Exception) { puts "Exception recued! #{ex.message}" }
Schedule.exception_handler = handler
- Fork it ( https://github.com/hugoabonizio/schedule.cr/fork )
- Create your feature branch (git checkout -b my-new-feature)
- Commit your changes (git commit -am 'Add some feature')
- Push to the branch (git push origin my-new-feature)
- Create a new Pull Request
- hugoabonizio Hugo Abonizio - creator, maintainer