[Twisted-Python] More daemonize() / OSX API / USING_FORK_WITHOUT_EXEC_etc.

Erik van Blokland erik at letterror.com
Fri Nov 5 18:46:49 EDT 2010


Hi,

A while back on Oct 13, 2010, at 7:20 PM, James Y Knight wrote:

> You need to avoid using or importing any OSX APIs until after the daemonization has occurred. Unfortunately, twisted executes the entire script file before daemonizing. [that's unfortunate for other reasons besides this, too]
> 
> Here's a corrected version of your script which works properly. It defers importing Quartz until the reactor is running, by moving it into a function called by reactor.callWhenRunning().

Deferring OSX API's until after daemonisation was the solution. My test script, fixed by James, works on macbook, but when I run it on a remote OSX server mini, it doesn't. It crashes as before with USING_FORK_WITHOUT_EXEC_IS_NOT_SUPPORTED_BY_FILE_MANAGER) . Both machines run the same versions of python, pyobjc, twisted.  Some digging showed that on the mini twisted.application.reactors imports zope.interface, which in turn runs this:
	__import__('pkg_resources').declare_namespace(__name__)
and this causes Carbon to be loaded, before daemonisation. I can't defer loading reactor because I need it to make things tick, so I'm stuck.

Could this be related to http://twistedmatrix.com/trac/ticket/4644 ?
Any clues to why pkg_resources would cause Carbon to load on one machine, but not on another?
Any clues to prevent it these modules from loading?

Local:
  System Version:	Mac OS X 10.6.4 (10F569)
  Kernel Version:	Darwin 10.4.0

Remote:
 System Version:	Mac OS X Server 10.6.4 (10F569)
  Kernel Version:	Darwin 10.4.0

Thanks,
Erik
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