Disabling DRbUndumped

Ruby
1

anyone got a slick way of temporaily disabling DRbUndumped?

-a

2

[email protected] schrieb:

anyone got a slick way of temporaily disabling DRbUndumped?

Ara, can you tell us a bit more, probably via a testcase?

Regards,
Pit

3

On Feb 9, 2007, at 13:49, [email protected] wrote:

anyone got a slick way of temporaily disabling DRbUndumped?

Hrm, you’d need to move #_dump around to get this to work. Since
#_dump isn’t defined on Object, raising TypeError or calling super
isn’t going to work, and I’m not smart enough to make it work.

4

On Sat, 10 Feb 2007, Eric H. wrote:

On Feb 9, 2007, at 13:49, [email protected] wrote:

anyone got a slick way of temporaily disabling DRbUndumped?

Hrm, you’d need to move #_dump around to get this to work. Since #_dump
isn’t defined on Object, raising TypeError or calling super isn’t going to
work, and I’m not smart enough to make it work.

i’ve just been doing

def marshal src
klass = src.class
dst = klass.allocate
src.instance_variables.each do |ivar|
…
…
…

because the objects in question are simply state… but it’s a work
around.

sigh.

-a

5

On Sat, Feb 10, 2007 at 06:49:59AM +0900, [email protected] wrote:

anyone got a slick way of temporaily disabling DRbUndumped?

Strained, but works. It can be made thread-safe quite easily also.

$ cat drb_client.rb
#!/usr/bin/env ruby
require 'drb'
require 'time_service'

DRb.start_service

r_obj = DRbObject.new_with_uri(ARGV.shift)
p r_obj
puts "-" * 40

def d(o)
  puts "OBJECT -> #{o.inspect}"
  p o.get_time
end

t = r_obj.time
d t

puts "\nDisabling undumped"
t.disable_undumped
t = r_obj.time
d t

puts "\nEnabling"
r_obj.enable_undumped(TimeServer)
t = r_obj.time
d t

$ ruby drb_client.rb  druby://localhost:50011
#<DRb::DRbObject:0xa7d9d4e0 @ref=nil,

@uri=“druby://localhost:50011”>
----------------------------------------
OBJECT -> #<DRb::DRbObject:0xa7d9ccfc @ref=-739674518,
@uri=“druby://localhost:50011”>
Sat Feb 10 17:04:04 +0100 2007

Disabling undumped
OBJECT -> #<TimeServer:0xa7d9bf3c>
Sat Feb 10 17:04:04 +0100 2007

Enabling
OBJECT -> #<DRb::DRbObject:0xa7d9b4ec @ref=-739674518,

@uri=“druby://localhost:50011”>
Sat Feb 10 17:04:04 +0100 2007

$ cat time_service.rb

require 'drb'
require 'suspend_undumped'

class TimeServer
  include DRb::DRbUndumped
  def get_time; return Time.now end
end

$ cat suspend_undumped.rb

module DRb::DRbUndumped
  disabled = @disabled = {}
  ::Kernel.module_eval do

old_kind_of = instance_method(:kind_of?)
define_method(:kind_of?) do |klass|
#puts “OBJ is #{self.inspect} in #{caller[0]}” if $DEBUG
if DRb::DRbUndumped == klass && disabled[self.class]
false
else
old_kind_of.bind(self).call(klass)
end
end
end

  define_method(:respond_to?) do |meth|

if disabled[self.class] && :_dump == meth
false
else
super
end
end

  # all these executed in the server
  def self.disable_undumped(klass)

@disabled[klass] = true
end

  def self.enable_undumped(klass)

@disabled.delete(klass)
end

  def disable_undumped

DRb::DRbUndumped.disable_undumped(self.class)
end
end

class Object
  def enable_undumped(klass)

in the server

DRb::DRbUndumped.enable_undumped(klass)
end
end

class DRb::DRbObject
  def enable_undumped(klass)

in the client

method_missing(:enable_undumped, klass)
end
end

Finally, a trivial server (just so the email is self-complete):

require 'drb'
require 'time_service'

URI = "druby://localhost:50011"

Service = Struct.new(:time, :foo)

obj = Service.new(TimeServer.new, nil)
DRb.start_service(URI, obj)

puts DRb.uri

DRb.thread.join
6

On Sun, 11 Feb 2007, Mauricio F. wrote:

On Sat, Feb 10, 2007 at 06:49:59AM +0900, [email protected] wrote:

anyone got a slick way of temporaily disabling DRbUndumped?

Strained, but works. It can be made thread-safe quite easily also.

coming it at from the other direction - NICE!

boy - it might be easier to patch drb though… seems like a good
feature to
have?

thanks a bunch - i’ll play with this

cheers.

-a

7

[email protected] schrieb:

(… mauricio’s as always fine solution …)

thanks a bunch - i’ll play with this

Ara, do you need to control this on the client or on the server? Per
object or per class? There are several possible implementations based on
Mauricio’s code. For example, with the following the disable/enable
methods work on a per object basis:

module DRbUndumped

 @undumped_disabled = {}

 def self.undumped_disabled? obj
   @undumped_disabled[ DRb.to_id(obj) ]
 end

 def self.disable_undumped obj
   @undumped_disabled[ DRb.to_id(obj) ] = true
 end

 def self.enable_undumped obj
   @undumped_disabled.delete DRb.to_id(obj)
 end

 def undumped_disabled?
   DRbUndumped.undumped_disabled? self
 end

 def disable_undumped
   DRbUndumped.disable_undumped self
 end

 def enable_undumped
   DRbUndumped.enable_undumped self
 end

 def kind_of? arg
   (arg != DRbUndumped || !undumped_disabled?) && super
 end

 def respond_to? arg
   (arg != :_dump || !undumped_disabled?) && super
 end

end

It doesn’t allow to re-enable DRbUndumped on the client side. If you
need this, the code has to be changed a little bit.

Regards,
Pit