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= How to develop Trac with Eclipse !PyDev =

Follow the instructions for ''Setting up the environment'' and ''Installing and configuring Trac'' on the [TracDev/DevelopmentEnvironmentSetup Developer setup for Trac] page, before configuring Eclipse and !PyDev.

== Installing and configuring Eclipse ==

 1. Install [http://www.eclipse.org Eclipse] (3.3 or newer will do).
 1. Install the [http://pydev.org PyDev] plugin for Eclipse.
 1. Alternatively, install [[http://brainwy.github.io/liclipse|LiClipse]], it comes with !PyDev already integrated.
 1. (Optional) Install either [http://subclipse.tigris.org Subclipse] or [http://www.eclipse.org/subversive/ Subversive] for Eclipse-integrated Subversion tools.
 1. Create a new project in Eclipse that contains the sources for trac
 1. In Eclipse, make sure that the PYTHONPATH in the project properties dialog includes the sources for trac and for genshi.
 1. Create an initial run configuration by clicking right on ''trac/web/standalone.py file'', and choosing ''Run As->Python Run''. Trac will complain that no environment has been set.
 1. Select ''Run->Open Run Dialog...'' and set the correct command line arguments in the ''arguments'' tab, eg. ''--port 8000 /path/to/myproject''. 
  * Note that the option --auto-reload will cause tracd to restart every time source code has been changed, but it seems to prevent debugging with !PyDev. This seems to have something to do way Trac reloads new instance as a child thread using "thread" library which doesn't seem to be compatible with !PyDev debugging. Googling revelead some hints that instead using "thread"-module you should use "threading"-module (higherlevel)
  * Note that if you debugging doesn't work with a plugin then remove the package from the install destination (eg. ''rm -Rf'') and soft link it from your source.
 1. You should now be able to run tracd, as well as to debug it using the same run configuration. To run the test cases, just click on a test folder and select ''Run->Python unit tests''

== Automatic translation compilation ==

If you want to setup automatic translation compilation it can be done very easily.

 1. Right click on trac project and select ''Properties''. Select ''Builders''. Click ''New''. Select ''Program''.
 1. Name builder, like 'Locale fi_FI builder'
 1. ''Main'' tab: 
  * ''Location'': click ''Browse File System...''. Select Python executable.
  * ''Working Directory'': set it to ''${project_loc}''
  * ''Arguments'': ''setup.py compile_catalog -f -l fi_FI'' (change to your locale)
 1. ''Refresh'' tab:
  * Check ''Refresh resources upon completion''.
  * Select ''Spesific resources'' and select ''trac/locale/fi_FI'' (select your locale)
 1. ''Build Options'' tab:
  * Check ''During auto builds''.
  * Check ''Specify working set of relevan resources''.[[BR]]
  * Click ''Specify resources...''. select ''trac/locale/fi_FI'' (select your locale, same as in step 4).
  *  Name it like ''fi_FI locale''.
 1. After modifying your message.po file you should get following output:
 {{{
  running compile_catalog
  compiling catalog 'trac/locale\\fi_FI\\LC_MESSAGES\\messages.po' to 'trac/locale\\fi_FI\\LC_MESSAGES\\messages.mo'
 }}}

If Trac is running, your changes will be effective immediately.

== pylint integration

Pylint is a validator and quality checker for the Python programming language. It can be integrated with !PyDev, see [http://pydev.org/manual_adv_pylint.html pydev.org] for details.

For developing Trac plugins, you should reference to all dependend eggs (such as Tarc, Genshi, Babel, etc.). To do this open  `Project > Properties`, go to node `PyDev - PYTHONPATH` and click on `Add zip/jar/egg/` in tab `External Libraries`. Search for your `Trac-$VERSION-.egg` and do the same for all required libraries (Genshi, Babel).

If you import from `pkg_resources` you need to add `#@UnresolvedImport` after it, because otherwise you get the error: `Unresolved import: resource_filename` (see [http://stackoverflow.com/questions/6336882/pylint-doesnt-like-pkg-resources-resource-filename stackoverflow-question] for details):

{{{#!py
from pkg_resources import resource_filename #@UnresolvedImport
}}}

== Remote Debugging

With Eclipse [http://pydev.org/ PyDev] it is possible to debug Trac remotely. This means you can evaluate all varaibles and "Step into" (`F5`), "Step over" (`F6`) and "Step out" (`F7`) of each line of code.

How to setup the remote debugger is described in [http://pydev.org/manual_adv_remote_debugger.html PyDev Manual]. Basically you need to follow these steps:
1. Go to the debug perspective
1. Start the remote debugger server
1. Make sure `pydevd.py` is in your pythonpath: the python file usually resides under `eclipse/plugins/org.python.pydev_x.x.x/pysrc/pydevd.py`

Then you can insert following code to start the debug mode (see [attachment:pydev_debug_screenshot.png Screenshot]):
{{{#!py
try: import pydevd;pydevd.settrace() #@UnresolvedImport
except ImportError: None # avoids throwing an Exception when not in debug mode
}}}

== Thanks ==

Originally these instructions were [http://groups.google.de/group/trac-dev/msg/235281558542b2ff posted on trac-dev list] by Joachim Hoessler.