Manually Removing Local Persistent Utilities

by Nathan Van Gheem — last modified Dec 13, 2010 02:11 PM

This document explains how you can manually remove local persistent utilities that were not properly removed from a product while uninstalling.

Update

There is now a useful tool available, wildcard.fixpersistentutilities, to address these issues TTW(Through The Web). I would suggest trying it before you go through this article.

Purpose

Occasionally you'll download and install a product in Plone that uses local persistent utilities. This usually seems pretty innocent in itself; however, it sometimes happens that when you uninstall the product and remove its egg from the file system, the utility is still registered. This will essentially break your instance unless you make the egg available again so the ZODB can reference the utilities during lookups. This how-to will explain how to remove these utilities manually.

Symptoms

You'll find zope throwing errors like this,

AttributeError: type object 'IQueue' has no attribute '__iro__'

AttributeError: type object 'ISalt' has no attribute '__iro__'

Prerequisites

You will need appropriate access to the zope server in order to run the site in debug mode.

Step by step

First off, fire up the instance in debug mode

./bin/instance debug

Get the site manager for your Plone instance. 'app' references the zope root.

sm = app.Plone.getSiteManager()

Then you'll want to import the guilty utility's interface, unregister it and delete it. It should look somethings like this,

from collective.product.interfaces import IUtility, INamedUtility

# for unnamed utility
util = sm.getUtility(IUtility)
sm.unregisterUtility(IUtility)
del util
sm.utilities.unsubscribe((), IUtility)
del sm.utilities.__dict__['_provided'][IUtility]
del sm.utilities._subscribers[0][IUtility]

#also for named utility
util = sm.queryUtility(INamedUtility, name='utility-name')
sm.unregisterUtility(util, INamedUtility, name='utility-name')
del util
del sm.utilities._subscribers[0][INamedUtility]

Now you need to commit your changes to the ZODB.

import transaction
transaction.commit()
app._p_jar.sync()

An Example

I found myself in this situation with the Singing and Dancing product so I'll just go through the code here to fix both a normal utility and named utility found in it.

from collective.singing.interfaces import ISalt
from collective.singing.async import IQueue
import transaction

portal = app.Plone
sm = portal.getSiteManager()

util_obj = sm.getUtility(ISalt)
sm.unregisterUtility(provided=ISalt)
del util_obj
sm.utilities.unsubscribe((), ISalt)
del sm.utilities.__dict__['_provided'][ISalt]
del sm.utilities._subscribers[0][ISalt]

util = sm.queryUtility(IQueue, name='collective.dancing.jobs')
sm.unregisterUtility(util, IQueue, name='collective.dancing.jobs')
del util
del sm.utilities._subscribers[0][IQueue]

Handling subscribers, adapters and utilities

sm = app.myportal.getSiteManager()
adapters = sm.utilities._adapters
for x in adapters[0].keys():
    if x.__module__.find("collective.myproduct") != -1:
      print "deleting %s" % x
      del adapters[0][x]
sm.utilities._adapters = adapters

subscribers = sm.utilities._subscribers
for x in subscribers[0].keys():
    if x.__module__.find("collective.myproduct") != -1:
      print "deleting %s" % x
      del subscribers[0][x]
sm.utilities._subscribers = subscribers

provided = sm.utilities._provided
for x in provided.keys():
    if x.__module__.find("collective.myproduct") != -1:
      print "deleting %s" % x
      del provided[x]
sm.utilities._provided = provided

from transaction import commit
commit()
app._p_jar.sync()

Removing portal tools

If you still have problems (re)installing products after you removed the broken local persistent components, you probably have to clean the Portal setup tool.You probably see something like this in the error log :

setup_tool = app.myportal.portal_setup
toolset = setup_tool.getToolsetRegistry()
if 'portal_myproduct' in toolset._required.keys():
    del toolset._required['portal_myproduct']
    setup_tool._toolset_registry = toolset

from transaction import commit
commit()
app._p_jar.sync()

References

I didn't by any means figure this all our on my own so please do not give me credit for it. Actually, most of this is shamelessly stolen. Thanks for the original fixers of the problem! Here are my references:

http://blog.fourdigits.nl/removing-a-persistent-local-utility
http://blog.fourdigits.nl/removing-a-persistent-local-utility-part-ii
http://plone.org/support/forums/addons#nabble-td3341437
http://74.125.155.132/search?q=cache:EMU7OpF6ekEJ:https://bugs.launchpad.net/singing-dancing/%2Bbug/363127+Error+Value:+type+object+'IQueue'+has+no+attribute+'__iro__'&cd=1&hl=en&ct=clnk&gl=us

Current