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|
#!/usr/local/bin/ruby -w
# $Id$
# included so we can test object types
require 'puppet'
require 'puppet/type'
module Puppet
# events are transient packets of information; they result in one or more (or none)
# subscriptions getting triggered, and then they get cleared
# eventually, these will be passed on to some central event system
class Event
# subscriptions are permanent associations determining how different
# objects react to an event
class Subscription
attr_accessor :source, :event, :target, :method
def initialize(hash)
@triggered = false
hash.each { |method,value|
# assign each value appropriately
# this is probably wicked-slow
self.send(method.to_s + "=",value)
}
Puppet.warning "New Subscription: '%s' => '%s'" %
[@source,@event]
end
# the transaction is passed in so that we can notify it if
# something fails
def trigger(transaction)
# this is potentially incomplete, because refreshing an object
# could theoretically kick off an event, which would not get run
# or, because we're executing the first subscription rather than
# the last, a later-refreshed object could somehow be connected
# to the "old" object rather than "new"
# but we're pretty far from that being a problem
if transaction.triggercount(self) > 0
Puppet.debug "%s has already run" % self
else
Puppet.debug "'%s' matched '%s'; triggering '%s' on '%s'" %
[@source,@event,@method,@target]
begin
if @target.respond_to?(@method)
@target.send(@method)
else
Puppet.debug "'%s' of type '%s' does not respond to '%s'" %
[@target,@target.class,@method.inspect]
end
rescue => detail
# um, what the heck do i do when an object fails to refresh?
# shouldn't that result in the transaction rolling back?
# XXX yeah, it should
Puppet.err "'%s' failed to %s: '%s'" %
[@target,@method,detail]
raise
#raise "We need to roll '%s' transaction back" %
#transaction
end
transaction.triggered(self)
end
end
end
attr_accessor :event, :object, :transaction
@@events = []
@@subscriptions = []
def Event.process
Puppet.warning "Processing events"
@@events.each { |event|
@@subscriptions.find_all { |sub|
#Puppet.warning "Sub source: '%s'; event object: '%s'" %
# [sub.source.inspect,event.object.inspect]
sub.source == event.object and
(sub.event == event.event or
sub.event == :ALL_EVENTS)
}.each { |sub|
Puppet.notice "Found sub"
sub.trigger(event.transaction)
}
}
@@events.clear
end
def Event.subscribe(hash)
if hash[:event] == '*'
hash[:event] = :ALL_EVENTS
end
sub = Subscription.new(hash)
# add to the correct area
@@subscriptions.push sub
end
def initialize(args)
unless args.include?(:event) and args.include?(:object)
raise "Event.new called incorrectly"
end
@event = args[:event]
@object = args[:object]
@transaction = args[:transaction]
Puppet.info "%s: %s" %
[@object,@event]
# initially, just stuff all instances into a central bucket
# to be handled as a batch
@@events.push self
end
end
end
#---------------------------------------------------------------
# here i'm separating out the methods dealing with handling events
# currently not in use, so...
class Puppet::NotUsed
#---------------------------------------------------------------
# return action array
# these are actions to use for responding to events
# no, this probably isn't the best way, because we're providing
# access to the actual hash, which is silly
def action
if not defined? @actions
puts "defining action hash"
@actions = Hash.new
end
@actions
end
#---------------------------------------------------------------
#---------------------------------------------------------------
# call an event
# this is called on subscribers by the trigger method from the obj
# which sent the event
# event handling should probably be taking place in a central process,
# but....
def event(event,obj)
Puppet.debug "#{self} got event #{event} from #{obj}"
if @actions.key?(event)
Puppet.debug "calling it"
@actions[event].call(self,obj,event)
else
p @actions
end
end
#---------------------------------------------------------------
#---------------------------------------------------------------
# subscribe to an event or all events
# this entire event system is a hack job and needs to
# be replaced with a central event handler
def subscribe(args,&block)
obj = args[:object]
event = args[:event] || '*'.intern
if obj.nil? or event.nil?
raise "subscribe was called wrongly; #{obj} #{event}"
end
obj.action[event] = block
#events.each { |event|
unless @notify.key?(event)
@notify[event] = Array.new
end
unless @notify[event].include?(obj)
Puppet.debug "pushing event '%s' for object '%s'" % [event,obj]
@notify[event].push(obj)
end
# }
#else
# @notify['*'.intern].push(obj)
end
#---------------------------------------------------------------
#---------------------------------------------------------------
# initiate a response to an event
def trigger(event)
subscribers = Array.new
if @notify.include?('*') and @notify['*'].length > 0
@notify['*'].each { |obj| subscribers.push(obj) }
end
if (@notify.include?(event) and (! @notify[event].empty?) )
@notify[event].each { |obj| subscribers.push(obj) }
end
Puppet.debug "triggering #{event}"
subscribers.each { |obj|
Puppet.debug "calling #{event} on #{obj}"
obj.event(event,self)
}
end
#---------------------------------------------------------------
#---------------------------------------------------------------
end # Puppet::Type
|
