Monthly Archives: 2009-7

Debugging Plone with Eclipse and PyDev remote debugger

Posted on by
1

Plone is a very heavy Python CMS containing thousands of modules. PyDev is Python extension for Eclipse IDE. Plone doesn’t run very well in PyDev debug mode:

  • Debug mode is many times slower than normal Python execution
  • At least on  some Linux system OS limitations prevent proper running [1]

But you can still use Eclipse and PyDev remote debugger to debug your software.

  • All communications happen over sockets so you can debug software running on test server besides local machine
  • Downsite is that you need to manually place pydevd.settrace() call to your code instead of just right clicking the line and choosing Set Breakpoint from menu

pydev_and_plone In both cases you need to use a custom non-forking Plone launch script from Plone and Eclipse tutorial which prevents Zope to escape itself into a child process and keeps the debug process information intact.

1. PyDev Extension remote debugger

Note that you need the commercial PyDev Extension license, this does not work with the basic plug-in. Free evaluation trial available. Get it here.

Benefits

  • GUI stepping support
  • Inspect Python run-time environment and variables using GUI
  • Better integration with Eclipse console

2. Setting up local remote debugger

0. Install Eclipse. Do a local install, do not trust your Linux distribution package installation. http://johnpaulett.com/2009/06/26/install-eclipse-galileo-3-5-on-ubuntu-jaunty-9-04/

1. Set up idelauncher.py for your Zope application server

2. Right-click your project in Eclipse. Put pydevd in your PyDev – PYTHONPATH -> External libraries. Mine (local Eclipse 3.5 install) is /home/moo/eclipse3.5/plugins/org.pyhon.pydev.debug.XXX/pysrc

3. Switch to Eclipse Debug perspective. Start pydevd server by clicking the icon with a bug and P letter.

3. Start your Plone instance / unit tests idelauncher.py using Run (play icon – not debug). The debug server stays active even if you terminate the application launcher run.

4. When your code runs to *import pydevd ; pydevd.settrace()* (no underscore in settrace()) you should be able to start examining your site in the debugger

Now you can

  • Examine and edit local variables in Variables view
  • Execute Python console commands
  • Examine different threads (kind of pointless with Plone…)

Note: Python console behaves funnily. You need to enter the commands to Console -> Display selected console (computer icon) -> Debug server view and output will appear  Console -> Display selected console (computer icon) -> your launcher name view.

3. Remote debugging not enabled

The following exception means that your pydevd server is not running. Click the P bug icon before running the launcher.

Traceback (most recent call last):
  File "/home/moo/eclipse3.5/plugins/org.python.pydev.debug_1.4.7.2843/pysrc/pydevd.py", line 624, in trace_dispatch
    return dbFrame.trace_dispatch(frame, event, arg)
  File "/home/moo/eclipse3.5/plugins/org.python.pydev.debug_1.4.7.2843/pysrc/pydevd_frame.py", line 107, in trace_dispatch
    raise
  File "/home/moo/eclipse3.5/plugins/org.python.pydev.debug_1.4.7.2843/pysrc/pydevd_frame.py", line 102, in trace_dispatch
    self.doWaitSuspend(thread, frame, event, arg)
  File "/home/moo/eclipse3.5/plugins/org.python.pydev.debug_1.4.7.2843/pysrc/pydevd_frame.py", line 25, in doWaitSuspend
    self._args[0].doWaitSuspend(*args, **kwargs)
  File "/home/moo/eclipse3.5/plugins/org.python.pydev.debug_1.4.7.2843/pysrc/pydevd.py", line 532, in doWaitSuspend
    def doWaitSuspend(self, thread, frame, event, arg): #@UnusedVariable
  File "/home/moo/eclipse3.5/plugins/org.python.pydev.debug_1.4.7.2843/pysrc/pydevd.py", line 539, in doWaitSuspend
    self.writer.addCommand(cmd)

4. Pydevd and Linux Resource temporarily unavailable

[1] I get the following Resource temporarily unavailable traceback when I try to run PyDev debugger against Plone – I tried to pindown the reason using strace, but no luck. Applies both for unit testing and for the actual instance launch.

Installing PloneLanguageTool ... done (0.174s)
Running Products.SitsHospital.tests.rememberbase.RememberProfileLayer tests:
  Set up Products.PloneTestCase.layer.ZCML
Traceback (most recent call last):
...
  File "/home/moo/sits/parts/zope2/lib/python/zope/testing/testrunner.py", line 688, in setup_layer
    setup_layer(base, setup_layers)
  File "/home/moo/sits/parts/zope2/lib/python/zope/testing/testrunner.py", line 692, in setup_layer
    layer.setUp()
  File "/home/moo/sits/parts/plone/PloneTestCase/layer.py", line 17, in setUp
...
  File "/usr/lib/python2.4/xml/sax/xmlreader.py", line 123, in parse
    self.feed(buffer)
  File "/usr/lib/python2.4/xml/sax/expatreader.py", line 207, in feed
    self._parser.Parse(data, isFinal)
  File "/usr/lib/python2.4/xml/sax/expatreader.py", line 348, in end_element_ns
    self._cont_handler.endElementNS(pair, None)
  File "/home/moo/sits/parts/zope2/lib/python/zope/configuration/xmlconfig.py", line 349, in endElementNS
    self.context.end()
  File "/home/moo/sits/parts/zope2/lib/python/zope/configuration/config.py", line 544, in end
    self.stack.pop().finish()
  File "/home/moo/sits/parts/zope2/lib/python/zope/configuration/config.py", line 692, in finish
    actions = self.handler(context, **args)
  File "/home/moo/sits/parts/plone/PlacelessTranslationService/patches.py", line 27, in compile_translations
    func(*args, **kwargs)
  File "/home/moo/sits/eggs/zope.i18n-3.7.0-py2.4.egg/zope/i18n/zcml.py", line 57, in registerTranslations
    for language in os.listdir(path):
zope.configuration.xmlconfig.ZopeXMLConfigurationError: File "/home/moo/sits/parts/instance/etc/site.zcml", line 5.2-5.37
    ZopeXMLConfigurationError: File "/home/moo/sits/parts/zope2/lib/python/Products/Five/configure.zcml", line 6.2-6.30
    ZopeXMLConfigurationError: File "/home/moo/sits/parts/zope2/lib/python/Products/Five/i18n.zcml", line 24.4-24.52
    OSError: [Errno 11] Resource temporarily unavailable: '/home/moo/sits/parts/zope2/lib/python/zope/app/locales'
Debugging Plone with PyDev Extensions remote debugger

Plone is a very heavy Python CMS containing thousands of modules. Plone doesn’t run very well in PyDev debug mode (normal process launch):

* Debug mode is many times slower than normal execution

* At least on Linux some system limitations prevent proper running [1]

You can still use PyDev remote debugger to debug your software http://fabioz.com/pydev/manual_adv_remote_debugger.html

* All communications happen over sockets so you can debug software running on test server besides local machine

* Downsite is that you need to manually place pydevd.settrace() call to your code instead of just right clicking the line and choosing Set Breakpoint from menu

In both cases you need to use a custom non-forking launch script which prevents Zope to escape itself into a child process and keeps the debug process information intact.

PyDev Extension remote debugger

Note that you need the commercial PyDev Extension license, this does not work with the basic plug-in. Free evaluation trial available. Get it here. http://fabioz.com/pydev/download.html

Benefits

– GUI stepping support

– Inspect Python run-time environment and variables using GUI

– Better integration with Eclipse console

Setting up local remote debugger

0. Install Eclipse. Do a local install, do not trust your Linux distribution package installation. http://johnpaulett.com/2009/06/26/install-eclipse-galileo-3-5-on-ubuntu-jaunty-9-04/

1. Set up idelauncher.py for your Zope application server

2. Right-click your project in Eclipse. Put pydevd in your PyDev – PYTHONPATH -> External libraries. Mine (local Eclipse 3.5 install) is /home/moo/eclipse3.5/plugins/org.pyhon.pydev.debug.XXX/pysrc

3. Switch to Eclipse Debug perspective. Start pydevd server by clicking the icon with a bug and P letter.

3. Start your Plone instance / unit tests idelauncher.py using Run (play icon – not debug). The debug server stays active even if you terminate the application launcher run.

4. When your code runs to *import pydevd ; pydevd.settrace()* (no underscore in settrace()) you should be able to start examining your site in the debugger

Now you can

– Examine and edit local variables in Variables view

– Examine different threads (kind of pointless with Plone…)

– Execute Python console commands

Note: Python console behaves funnily. You need to enter the commands to Console -> Display selected console (computer icon) -> Debug server view and output will appear  Console -> Display selected console (computer icon) -> your launcher name view.

Remote debugging not enabled

The following exception means that your pydevd server is not running. Click the P bug icon before running the launcher.

Traceback (most recent call last): File “/home/moo/eclipse3.5/plugins/org.python.pydev.debug_1.4.7.2843/pysrc/pydevd.py”, line 624, in trace_dispatch return dbFrame.trace_dispatch(frame, event, arg) File “/home/moo/eclipse3.5/plugins/org.python.pydev.debug_1.4.7.2843/pysrc/pydevd_frame.py”, line 107, in trace_dispatch raise File “/home/moo/eclipse3.5/plugins/org.python.pydev.debug_1.4.7.2843/pysrc/pydevd_frame.py”, line 102, in trace_dispatch self.doWaitSuspend(thread, frame, event, arg) File “/home/moo/eclipse3.5/plugins/org.python.pydev.debug_1.4.7.2843/pysrc/pydevd_frame.py”, line 25, in doWaitSuspend self._args[0].doWaitSuspend(*args, **kwargs) File “/home/moo/eclipse3.5/plugins/org.python.pydev.debug_1.4.7.2843/pysrc/pydevd.py”, line 532, in doWaitSuspend def doWaitSuspend(self, thread, frame, event, arg): #@UnusedVariable File “/home/moo/eclipse3.5/plugins/org.python.pydev.debug_1.4.7.2843/pysrc/pydevd.py”, line 539, in doWaitSuspend self.writer.addCommand(cmd)

[1] I get the following traceback when I try to run PyDev debugger against Plone – I tried to pindown the reason using strace, but no luck:

Installing PloneLanguageTool … done (0.174s) Running Products.SitsHospital.tests.rememberbase.RememberProfileLayer tests: Set up Products.PloneTestCase.layer.ZCML Traceback (most recent call last): … File “/home/moo/sits/parts/zope2/lib/python/zope/testing/testrunner.py”, line 688, in setup_layer setup_layer(base, setup_layers) File “/home/moo/sits/parts/zope2/lib/python/zope/testing/testrunner.py”, line 692, in setup_layer layer.setUp() File “/home/moo/sits/parts/plone/PloneTestCase/layer.py”, line 17, in setUp … File “/usr/lib/python2.4/xml/sax/xmlreader.py”, line 123, in parse self.feed(buffer) File “/usr/lib/python2.4/xml/sax/expatreader.py”, line 207, in feed self._parser.Parse(data, isFinal) File “/usr/lib/python2.4/xml/sax/expatreader.py”, line 348, in end_element_ns self._cont_handler.endElementNS(pair, None) File “/home/moo/sits/parts/zope2/lib/python/zope/configuration/xmlconfig.py”, line 349, in endElementNS self.context.end() File “/home/moo/sits/parts/zope2/lib/python/zope/configuration/config.py”, line 544, in end self.stack.pop().finish() File “/home/moo/sits/parts/zope2/lib/python/zope/configuration/config.py”, line 692, in finish actions = self.handler(context, **args) File “/home/moo/sits/parts/plone/PlacelessTranslationService/patches.py”, line 27, in compile_translations func(*args, **kwargs) File “/home/moo/sits/eggs/zope.i18n-3.7.0-py2.4.egg/zope/i18n/zcml.py”, line 57, in registerTranslations for language in os.listdir(path): zope.configuration.xmlconfig.ZopeXMLConfigurationError: File “/home/moo/sits/parts/instance/etc/site.zcml”, line 5.2-5.37 ZopeXMLConfigurationError: File “/home/moo/sits/parts/zope2/lib/python/Products/Five/configure.zcml”, line 6.2-6.30 ZopeXMLConfigurationError: File “/home/moo/sits/parts/zope2/lib/python/Products/Five/i18n.zcml”, line 24.4-24.52 OSError: [Errno 11] Resource temporarily unavailable: ‘/home/moo/sits/parts/zope2/lib/python/zope/app/locales’

Scripting Google analytics for multidomain site

Posted on by
1

We are running few Plone sites which use top level domain (TLD) to identify the site language.

Like many other CMSs out there,  Plone has only one box to enter Google Analytics script snippet.  It is often desirable to use different tracker for different domain and different language combinations, but Google itself doesn’t provide any fancy generator to create complex page tracking code.

Page tracker code, though looks little difficult when spit out by Google Analytics, is just normal Javascript.  You can make the condition to choose the appropriate page tracker id in Javascript itself using document.location property and this way you don’t need to mess with your page templates to create separate tracking Javascript snippet slots.

Here is an example what you can toss in to Plone site setup -> site -> JavaScript for web statistics support:

<script type="text/javascript">
var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");
document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));
</script>

<script type="text/javascript">
try {
// Choose page tracker id according to domain
  var domains = document.location.hostname.split(".");
  var tld = domains[domains.length-1];
if(tld == "fi") {
  // .fi
  pageTracker = _gat._getTracker("UA-8819100-1");
} else {
  // .com
  pageTracker = _gat._getTracker("UA-8819100-4");
}
pageTracker._trackPageview();
} catch(err) {
}

</script>

This is used on www.twinapex.com and www.twinapex.fi sites.

Use console.log(err) to output possible Javascript in catch {} errors using Firebug.

Autoconfiguring dual monitors on Ubuntu

Posted on by
5

The following shell script is a helper script for laptop users who connect an external monitor now and then to their laptop. Since Ubuntu does not provide clever ways to arrange desktop or detect connected displays, you need to run the script from terminal when you change your monitor configuration.

  • detect the numbers of monitors you have attached
  • Activate the second (external) monitor if there are two monitors
  • Use the external monitory as the primary display, otherwise use internal display as a primary display
  • Move your taskbars to the primary display

It is based on disper tool by Willem van Engen. For now (2009), it’s nVidia only. ATI support could be possible.

#!/bin/sh
#
# Detect displays and move panels to the primary display
#
# Copyright 2009 Twinapex Research
#
# Author <mikko.ohtamaa@twinapex.com>
#

# disper command will detect and configure monitors
disper --displays=auto -e

# parse output from disper tool how many displays we have attached
# disper prints 2 lines per displer
lines=`disper -l|wc -l`

display_count=$((lines / 2))

echo $display_count

echo "Detected display count:" $display_count

# Make sure that we move panels to the correct display based
# on the display count
if [ $display_count = 1 ] ; then
   echo "Moving panels to the internal LCD display"
   gconftool-2 \
        --set "/apps/panel/toplevels/bottom_panel_screen0/monitor" \
        --type integer "0"
   gconftool-2 \
        --set "/apps/panel/toplevels/top_panel_screen0/monitor" \
        --type integer "0"
else
   echo "Moving panels to the external display"
   gconftool-2 \
        --set "/apps/panel/toplevels/bottom_panel_screen0/monitor" \
        --type integer "1"
   gconftool-2 \
        --set "/apps/panel/toplevels/top_panel_screen0/monitor" \
        --type integer "1"
fi