Eclipse/pydev and buildout

Pydev has a nice code completion feature when editing Python code. You start typing a name, and Eclipse/Pydev offers context specific completions with call tips that saves a lot of time when programming for a hugh framework like Plone.

This requires to stuff somehow the PYTHONPATH for your project. This is fairly easy with a Plone bundle install tarball, where you just need to provide the paths to the Products directory, the lib/python of your instance and the global Zope $SOFTWARE_HOME.

With an instance created with buildout, things are not as straightforward. Such an instance is made of tons of eggs that are not in the standard "site-packages", in addition, Zope 2 style products may be located in various places. Adding all this manually in the Pydev project PYTHONPATH is a real nightmare.

Hopefully we have two recipe companions who can help us a lot configuring Eclipse + Pydev on your buildout instance:

From now we assume you already have a ready Plone 3.x instance.

With Eclipse, create a new Pydev project, say at the root of your buildout. Do not add anything to the Pydev - PYTHONPATH of that project. Now quit Eclipse. Your instance root should have a .pydevproject file.

Open your buildout.cfg and add that stuff:

zope-directory = /path/to/your/Zope-2.10.5
parts =
# Do not add parts that add eggs or products after the above parts
# we need this (a Products directory with symlinks to all plone products)
# to have completion of code in the Products namespace
recipe = iw.recipe.cmd:py
on_install = true
cmds =
      >>> import os
      >>> dirs = """${instance:products}""".split("\n")
      >>> prodlinks = os.path.join("""${buildout:directory}""".strip() , 'pydevlinks')
      >>> Products = os.path.join(prodlinks,'Products')
      >>> if not os.path.isdir(prodlinks): os.mkdir(prodlinks)
      >>> if not os.path.isdir(Products): os.mkdir(Products)
      >>> file(os.path.join(Products , ''),'w').write('#')
      >>> for dir in dirs:
      >>>     if not dir: continue
      >>>     for product in [os.path.join(dir,a) for a in os.listdir(dir) if os.path.isdir(os.path.join(dir,))]:
      >>>         linkname = os.path.join(Products, os.path.basename(product))
      >>>         if not os.path.islink(linkname): os.symlink(product,linkname)

recipe =
eggs = ${instance:eggs}

# See [make_pydev_init_files] below
extra_paths =
pydevproject_path = ${buildout:directory}/.pydevproject

Re-run your buildout. That's OK? Now open Eclipse and view your project properties. Et voilĂ ...

Eclipse dashboard

PYTHONPATH of Eclipse / Pydev environment

As you can see we use "os.symlink" to fake a products hierarchy. Windows (NTFS) users should install a symlink tool like "junction" and tweak the script of the make_pydev_init_files part.


do not change manually anything that's in the /prodlinks directory of your buildout unless...

Many thanks to Tim Knapp and Sylvio for the hints in the products developers mailing list. Now this is in a blog.

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