Slave-0.0.1

Ruby
1

URIS

http://codeforpeople.com/lib/ruby/slave/
http://rubyforge.org/frs/?group_id=1024&release_id=5631

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          # object becomes drb server in

another
# process

 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

 obj = slave.object

                                 #
 p obj.method                    # call a method on drb server in

another
# process

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

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

INSTALL

gem install slave

enjoy.

-a

2

Ara,

I am trying to use your package on Windows. I’m running into an issue at
line 341 of slave.rb:

@pipe.fcntl Fcntl::F_SETFD, Fcntl::FD_CLOEXEC

I’m curious what these flags mean and what their equivalent on Windows
might
be (if any).

I already solved a couple of issues (well, hacked around them):

  1. No fork() on windows. Solved by installing Daniel B.'s
    win32-process
    gem
  2. “drbunix” URI fails on non-unix. Solved by passing nil to
    Drb.start_service (ugly hack, hoping to make it cleaner later)

Thanks for any help!

Justin

3

On Fri, 9 Jun 2006, Justin B. wrote:

hi justin-

I am trying to use your package on Windows. I’m running into an issue at
line 341 of slave.rb:

@pipe.fcntl Fcntl::F_SETFD, Fcntl::FD_CLOEXEC

I’m curious what these flags mean and what their equivalent on Windows might
be (if any).

it means that, should the parent do something like

exec ‘another_program.exe’

the pipe will be closed. it’s important since pids are recycled and
pipes
transfered the slave would live on for while - perhaps indefinitely.

of course it’s possible that behaviour is desireable, but then a zombie
would
also be created… anyhow, for hacking it’s safe to comment that out.

I already solved a couple of issues (well, hacked around them):

  1. No fork() on windows. Solved by installing Daniel B.'s win32-process
    gem
  2. “drbunix” URI fails on non-unix. Solved by passing nil to
    Drb.start_service (ugly hack, hoping to make it cleaner later)

this could easily be configured - check out how the other stuff is
configured
and do something like allow the ENV var ‘SLAVE_DRB_PROTOCOL’ to override
this… perhaps a better option might be

Drb.start_server ‘drb://localhost.localdomain:0’

note that ‘nil’ here doesn’t work on macs for some reason…

i’m running out the door now, but i’d love to make this work on windows

  • just
    for the challenge. maybe dan can lend a hand? :wink:

maybe we can work together and make another release that’s portable.
ping me
offline if your’re interested.

cheers.

-a

4

Ara.T.Howard wrote:

http://codeforpeople.com/lib/ruby/slave/
…
the Slave class forks a process and starts a drb server in the child
…
slave = Slave::new MyClass::new, ‘pulse_rate’ => 10

‘Master’ and ‘Slave’ labels unacceptable.

“Based on the cultural diversity and sensitivity of Los A. County,
this is not an acceptable identification label.”

http://www.cnn.com/2003/TECH/ptech/11/26/master.term.reut/

Enjoy,
Dave

5

Cloexec doesn’t exist on Windows. It would be meaningless anyway,
because
there’s no notion of a fork. In effect, everything is cloexec.

6

On Fri, 9 Jun 2006, Francis C. wrote:

Cloexec doesn’t exist on Windows. It would be meaningless anyway, because
there’s no notion of a fork. In effect, everything is cloexec.

everything on windows is meaningless to me :wink: care to review the code
and
suggest a way to make it portable?

cheers.

-a

7

On Jun 8, 2006, at 5:58 PM, [email protected] wrote:

note that ‘nil’ here doesn’t work on macs for some reason…

IPv6?

–
Eric H. - [email protected] - http://blog.segment7.net
This implementation is HODEL-HASH-9600 compliant

http://trackmap.robotcoop.com