# Slave-0.2.0 **URL:** \ **Category:** Ruby\ **Created:** [September 24, 2006, 12:56am UTC](https://www.ruby-forum.com/t/slave-0-2-0/69769 "2006-09-24T00:56:17Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [September 24, 2006, 12:56am UTC](https://www.ruby-forum.com/t/slave-0-2-0/69769/1 "2006-09-24T00:56:17Z")
SYNOPSIS the Slave class forks a process and starts a drb server in the child using any object as the server. the process is detached so it is not required (nor possible) to wait on the child pid. a Heartbeat is set up between the parent and child processes so that the child will exit of the parent exits for any reason - preventing orphaned slaves from running indefinitely. the purpose of Slaves is to be able to easily set up a collection of objects communicating via drb protocols instead of having to use IPC. typical usage: ``` obj = AnyClass::new slave = Slave::new obj p slave.object # handle on drb object p slave.uri # uri of the drb object p slave.socket # unix domain socket path for drb ``` object p slave.psname # title shown in ps/top other usage: set the pulse\_rate used for the Heartbeat ``` slave = Slave::new MyClass::new, 'pulse_rate' => 10 ``` same ``` Slave::pulse_rate = 10 slave = Slave::new MyClass::new ``` same ``` ENV['SLAVE_PULSE_RATE'] = 10 slave = Slave::new MyClass::new ``` to avoid having a copy of the object in both the parent and child use the block form ``` slave = Slave::new{ Server::new } # copy only in child! server = slave.object ``` if both an object AND a block are passed the object is passed to the block in the child process ``` slave = Slave::new(Server::new){|server| p 'in child!' } ``` slaves may be configured via the environment, the Slave class, or via the ctor for object itself. attributes which may be configured include ``` * socket_creation_attempts * pulse_rate * psname * debug ``` HISTORY 0.2.0: incorporated joel vanderWerf’s patch such that, if no object is passed the block is used to create one ONLY in the child. this avoids having a copy in both parent and child is that needs to be avoided due to, for instance, resource consumption. 0.0.1: - patch from Logan C. adds block form to slave new, block is run in the child ``` - added a few more samples/* - added Slave#wait - added status information to slaves - added close-on-exec flag to pipes in parent process ``` 0.0.0: - initial version enjoy. -a ---
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [September 24, 2006, 6:28am UTC](https://www.ruby-forum.com/t/slave-0-2-0/69769/2 "2006-09-24T06:28:43Z")
On Sep 23, 2006, at 3:52 PM, removed\_email\_address@domain.invalid wrote: > parent exits > for any reason - preventing orphaned slaves from running > indefinitely. the > purpose of Slaves is to be able to easily set up a collection of > objects > communicating via drb protocols instead of having to use IPC. > > -a ``` This is a great library Ara, I am writing a library that wraps up ``` the slave lib into another interface for controlling jobs with timers and a few other things. So the master process holds a thread pool with references to slave classes in it so that you can set a limit on the number of running slaves. Using it to offload jobs from a rails app to not hold up the http flow. I have a question though. What would be the cleanest way to have a slave class signal that it is finished working and needs to be kill’ed. I know there is the shutdown method that you could call from the master process to shutdown a slave. But is there something similar that can be called from a slave process? Or should I just let the slave process exit! and let the heartbeat cleanup after the dead slaves? Thanks -Ezra ---
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [September 24, 2006, 5:58pm UTC](https://www.ruby-forum.com/t/slave-0-2-0/69769/3 "2006-09-24T17:58:01Z")
On Sun, 24 Sep 2006, Ezra Z. wrote: > just let the slave process exit! and let the heartbeat cleanup after > the dead slaves? hmmm. good question. i could add a feature where at\_exit handlers could be added, somthing like s = Slave.new( :at\_exit =\> lambda{}){ do\_child\_stuff } would that be sufficient? -a ---
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [September 24, 2006, 11:40pm UTC](https://www.ruby-forum.com/t/slave-0-2-0/69769/4 "2006-09-24T23:40:42Z")
On Sep 24, 2006, at 8:57 AM, removed\_email\_address@domain.invalid wrote: > > not hold up the http flow. I have a question though. What would > > -a > Ara- ``` Yeah that would work fine I think. So that would call the lambda ``` when the child process calls exit! ? Is there any way for a slave to call back to the parent process? Or is there a way to get the drb uri of the parent from the child? ``` Thanks for slave and all your other codeforpeople ;) I have learned ``` a lot by reading through your code and by googling “cat a.rb” 😉 Cheers- -Ezra