Module: ActsAsService

Defined in:

lib/acts_as_service.rb

Overview

module that makes it easy to turn a class into a service, giving it methods like stop, start, restart for easy cronjobbage, etc.

simply require ‘acts_as_service’ in your class’ file and then call acts_as_service in your class definition, then implement a few required and option methods:

- required:
   - self.perform_work_chunk: do a chunk of work that the service is intended
                              to do. note that this method should return
                              periodically to enable shutdown. alternatively,
                              your method /could/ (but not recommended) check
                              the status to see if it's set to SHUTTING_DOWN
                              and return if so. otherwise, the shutdown
                              by this module will not work.

• optional:

  - self.service_name: return the string name of the service.
                       default is the class name (without module prefixes)
  - self.service_pid_filename: path to the file that should contain the PID for
                               the process while it's running.
                               default is #{RAILS_ROOT}/tmp/pids/<underscore version of service name>
  - self.sleep_time: seconds to sleep between calls to peform_work_chunk
                     default: no sleep till brooklyn!
  - self.sleep_check_timeout: while 'sleeping' between work chunks, how many
                              seconds to sleep between checking if the
                              service has been shut down. default is 2 seconds,
                              but you may want to override to make shorter
                              (will give better resolution on sleep_time, but
                              uses a little more cpu) or longer (if you don't
                              care about how quickly the service shuts down)
  - self.after_start: a hook to run a method after the service is started
                      but before first call to perform_work_chunk
  - self.before_stop: a hook to run a method before final shutdown (and
                      after last run to perform_work_chunk)
  

you can also call self.shutdown() from within your perform_work_chunk code to initiate a shutdown (don’t just exit() because there’s pidfile cleanup etc. to peform).

if you’d like to have long-running work chunks that periodically check for shutdowns, you can call _shutting_down? at any point, which will return true if a shutdown has been initiated. However, recommend putting reasonable amounts of work in each chunk and letting this service infrastructure manage the decision-making about shutting down…it’ll in general keep your code cleaner.

# my_service.rb:

require ‘acts_as_service’

class MyService

acts_as_service

# ... define methods

end

---

Defined Under Namespace

Modules: ClassMethods

Constant Summary

ACTS_AS_SERVICE_RUNNING =

'running'

ACTS_AS_SERVICE_OTHER_RUNNING =

'other running'

ACTS_AS_SERVICE_STOPPED =

'stopped'

ACTS_AS_SERVICE_SHUTTING_DOWN =

'shutting down'

ACTS_AS_SERVICE_PID_NO_PROCESS =

'pid no process'

SLEEP_CHECK_TIMEOUT =

how long to sleep before checking to see if sleep time has elapsed…allows for sleeping for a long time between work chunks, but quicker response to shutdowns. this is measured in seconds this is the DEFAULT value if the service doesn’t define the sleep_check_timeout method itself

2

Class Method Summary

• .included(base) ⇒ Object

Class Method Details

.included(base) ⇒ Object

# File 'lib/acts_as_service.rb', line 74

def self.included(base)
  base.extend ClassMethods
end