[Web-SIG] Daemon server management
mso at oz.net
Fri Jun 10 00:00:36 CEST 2005
Shannon -jj Behrens said:
> On 6/9/05, mso at oz.net <mso at oz.net> wrote:
>> Shannon -jj Behrens said:
>> > I usually just write a wrapper that matches whatever OS I'm on. I.e.
>> > I sacrifice the cross-platform requirement. Creating a FreeBSD
>> > rc.sh-type script is quite simple. Perhaps I'm being naive.
>> I've got a similar situation now. I've been using start-stop-daemon on
>> Linux to daemonize a naive Quixote application, but there's no
>> wrapper for Mac OSX 10.3. We're looking at teaching the Python program
>> itself to daemonize, although I think that's less ideal than using a
>> platform-standard wrapper. There's a couple examples in the Python
>> Cookbook (search for "daemon"); this is the one we're going to try:
>> Essentially, your application calls a function and then continues,
>> blissfully unaware it's been forked. However, it doesn't make a PID
>> or change uid. These are essential for production services. We're
>> looking at extending the function to do these.
>> The top-level executable needs --pidfile, --user and --group flags or
>> equivalent. (start-stop-daemon uses --chuid USER:GROUP).
> I would give up root manually. Afterall, no library code knows when
> the right time is, eh?
Perhaps it should be a separate function then. I'm thinking mostly of
code reuse. It would be nice to have a common module Paste and Quixote
and others can use to handle daemonizing, one that works with Unix and Mac
But who does the stop operation? I guess the executable needs a --stop
flag, which would imply:
# === daemon.py ===
@param pidfile filename or None. If none, no PID file.
@param overwrite boolean. If false and PID file exists, abort.
If true and PID file exists but process doesn't, overwrite.
PURPOSE: a reference implementation for daemozing and PID creation.
@param user name or uid. None means don't change.
@param group name or gid. None means don't change.
PURPOSE: do the name-to-id lookup and change in one step.
@param pidfile filename.
As for the RC script itself, those are very OS dependent. For instance,
Gentoo, Red Hat, and Debian are all different. The best you can do is a
directory of sample RC scripts. But even the "right" sample can be wrong
if the target OS has recently changed a feature. The best advice is to
copy a currently-installed script on the target platform.
-- Mike Orr <mso at oz.net>
More information about the Web-SIG