Class: GlassOctopus::Runner

Inherits:
Object
  • Object
show all
Includes:
Singleton
Defined in:
lib/glass_octopus/runner.rb

Overview

A very simple runner that takes an app and handles graceful shutdown for SIGINT and SIGTERM.

The #run method alters the state of the process globally and irreversibly by registering signal handlers. The Runner class is a singleton and can only be started once.

Runner runs the application in the main thread. When a signal hits the process the control is transferred to the signal handler which will raise an Interrupt exception which kicks off the graceful shutdown. During shutdown no more messages are read because everything happens in the main thread.

Runner does not provide any meaningful error handling. Errors are logged and then the process exits with status code 1.

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.run(app) ⇒ void

This method returns an undefined value.

Shortcut to #run.



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# File 'lib/glass_octopus/runner.rb', line 23

def self.run(app)
  instance.run(app)
end

Instance Method Details

#run(app) ⇒ void

This method returns an undefined value.

Starts the application and blocks until the process gets a SIGTERM or SIGINT signal.

Parameters:

  • app —

    the application to run



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# File 'lib/glass_octopus/runner.rb', line 32

def run(app)
  return if running?
  running!

  # To support JRuby Ctrl+C as MRI does.
  # See: https://github.com/jruby/jruby/issues/1639
  trap(:INT)  { Thread.main.raise Interrupt }
  trap(:TERM) { Thread.main.raise Interrupt }

  app.run
rescue Interrupt
  app.logger.info("Shutting down...")
  app.shutdown
  app.logger.info("Bye.")
rescue => ex
  app.logger.fatal("#{ex.class} - #{ex.message}:")
  app.logger.fatal(ex.backtrace.join("\n")) if ex.backtrace
  exit(1)
end

#running? ⇒ Boolean

Determines whether the application is running or not.

Returns:

  • (Boolean) 


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# File 'lib/glass_octopus/runner.rb', line 54

def running?
  @running
end