132 lines
4.3 KiB
Ruby

module Vagrant
module Actions
# Base class for any class which will act as a runner
# for actions. A runner handles queueing up and executing actions,
# and executing the methods of an action in the proper order. The
# action runner also handles invoking callbacks that actions may
# request.
#
# # Executing Actions
#
# Actions can be executed by adding them and executing them all
# at once:
#
# runner = Vagrant::Actions::Runner.new
# runner.add_action(FooAction)
# runner.add_action(BarAction)
# runner.add_action(BazAction)
# runner.execute!
#
# Single actions have a shorthand to be executed:
#
# Vagrant::Actions::Runner.execute!(FooAction)
#
# Arguments may be passed into added actions by adding them after
# the action class:
#
# runner.add_action(FooAction, "many", "arguments", "may", "follow")
#
class Runner
include Vagrant::Util
class << self
# Executes a specific action, optionally passing in any arguments to that
# action. This method is shorthand to initializing a runner, adding a single
# action, and executing it.
def execute!(action_klass, *args)
runner = new
runner.add_action(action_klass, *args)
runner.execute!
end
end
# Returns an array of all the actions in queue. Because this
# will persist accross calls (calling {#actions} twice will yield
# exactly the same object), to clear or modify it, use the ruby
# array methods which act on `self`, such as `Array#clear`.
#
# @return [Array]
def actions
@actions ||= Actions::Collection.new
end
# Returns the first action instance which matches the given class.
#
# @param [Class] action_klass The action to search for in the queue
# @return [Object]
def find_action(action_klass)
actions.find { |a| a.is_a?(action_klass) }
end
# Add an action to the list of queued actions to execute. This method
# appends the given action class to the end of the queue. Any arguments
# given after the class are passed into the class constructor.
def add_action(action_klass, *args)
actions << action_klass.new(self, *args)
end
# Execute the actions in queue. This method can also optionally be used
# to execute a single action on an instance. The syntax for executing a
# single method on an instance is the same as the {execute!} class method.
def execute!(single_action=nil, *args)
if single_action
actions.clear
add_action(single_action, *args)
end
actions.duplicates!
actions.dependencies!
# Call the prepare method on each once its
# initialized, then call the execute! method
begin
[:prepare, :execute!, :cleanup].each do |method|
actions.each do |action|
action.send(method)
end
end
rescue Exception => e
# Run the rescue code to do any emergency cleanup
actions.each do |action|
action.rescue(e)
end
# If its an ActionException, error and exit the message
if e.is_a?(ActionException)
error_and_exit(e.key, e.data)
return
end
# Finally, reraise the exception
raise
end
# Clear the actions
actions.clear
end
# Invokes an "around callback" which invokes before_name and
# after_name for the given callback name, yielding a block between
# callback invokations.
def invoke_around_callback(name, *args)
invoke_callback("before_#{name}".to_sym, *args)
yield
invoke_callback("after_#{name}".to_sym, *args)
end
# Invokes a single callback. This method will go through each action
# and call the method given in the parameter `name` if the action
# responds to it.
def invoke_callback(name, *args)
# Attempt to call the method for the callback on each of the
# actions
results = []
actions.each do |action|
results << action.send(name, *args) if action.respond_to?(name)
end
results
end
end
end
end