'Daemonizing' a script

ruby-talk
1

I got this code from Webrick::Daemon that is supposed to turn a ruby
script into a daemon. Though I don’t fully understand it, I guess that
means that it detaches it from the terminal that called it. The thing
is, when I run the script without the daemonizing code it works fine,
but when I add the following code it silently croaks. Does anybody know
what might be going wrong?

Thanks,
Carl Youngblood

···

#------------------------------

the following lines “daemonize” this script

exit!(0) if fork
Process::setsid
exit!(0) if fork
Dir::chdir("/")
File::umask(0)
[ STDIN, STDOUT, STDERR ].each{|io|
io.reopen("/dev/null", “r+”)
}

This is a session storage daemon which can be shared by multiple FCGI

processes. It’s just a hash which is enabled for DRb access.

require 'drb’
require ‘include/localsettings’

session_data = Hash.new
DRb.start_service(“druby://127.0.0.1:#{SESSION_PORT.to_s}”, session_data)
DRb.thread.join

2

What do you mean by “silently croaks”? Like nothing happens, just a
prompt? Did you check your processes? As a result of this code there
must be a detached process with parent id 1 that do not have
controlling terminal. Try:

ps -ef |grep ruby

and scan for a corresponding process (it is Unix, isn’t it? It may not
work on Windows).

···

On Dec 19, 2003, at 15:11, Carl Youngblood wrote:

I got this code from Webrick::Daemon that is supposed to turn a ruby
script into a daemon. Though I don’t fully understand it, I guess
that means that it detaches it from the terminal that called it. The
thing is, when I run the script without the daemonizing code it works
fine, but when I add the following code it silently croaks. Does
anybody know what might be going wrong?

Thanks,
Carl Youngblood

#------------------------------

the following lines “daemonize” this script

exit!(0) if fork
Process::setsid
exit!(0) if fork
Dir::chdir(“/”)
File::umask(0)
[ STDIN, STDOUT, STDERR ].each{|io|
io.reopen(“/dev/null”, “r+”)
}

This is a session storage daemon which can be shared by multiple FCGI

processes. It’s just a hash which is enabled for DRb access.

require ‘drb’
require ‘include/localsettings’

session_data = Hash.new
DRb.start_service(“druby://127.0.0.1:#{SESSION_PORT.to_s}”,
session_data)
DRb.thread.join

Sincerely,
Gennady Bystritsky

3

Never mind. I feel sheepish for bothering the list with this. I just
needed to turn off error output to /dev/null to see what was going on.
Sorry. :frowning:

Carl Youngblood wrote:

···

I got this code from Webrick::Daemon that is supposed to turn a ruby
script into a daemon. Though I don’t fully understand it, I guess that
means that it detaches it from the terminal that called it. The thing
is, when I run the script without the daemonizing code it works fine,
but when I add the following code it silently croaks. Does anybody know
what might be going wrong?

Thanks,
Carl Youngblood

#------------------------------

the following lines “daemonize” this script

exit!(0) if fork
Process::setsid
exit!(0) if fork
Dir::chdir(“/”)
File::umask(0)
[ STDIN, STDOUT, STDERR ].each{|io|
io.reopen(“/dev/null”, “r+”)
}

This is a session storage daemon which can be shared by multiple FCGI

processes. It’s just a hash which is enabled for DRb access.

require ‘drb’
require ‘include/localsettings’

session_data = Hash.new
DRb.start_service(“druby://127.0.0.1:#{SESSION_PORT.to_s}”, session_data)
DRb.thread.join

4

Carl Youngblood wrote:

Never mind. I feel sheepish for bothering the list with this. I just
needed to turn off error output to /dev/null to see what was going on.
Sorry. :frowning:

Ha, no sweat, Carl. We’ve all done it.

Hal