Daniel Nouri's Old Blog

Building the egg

1. Checkout a bundle of Plone that contains all the necessary products in the Products/ subdirectory
2. Run setup.py bdist_egg. This requires you to have setuptools installed.

The egg should be now in dist/Plone*egg, ready for installation. You can distribute your egg at this point.

Note: Currently there is a problem that prevents ATContentTypes' thirdparty package from being included. This should probably be fixed in ATContentTypes. For now, you need to put an empty __init__.py file into the Products/ATContentTypes/thirdparty directory.

Installing the egg

You can install the egg site-wide. With the effect that the Products will be available for import implicitly for every Zope 2 instance in the site. Doing this is very simple:

easy_install dist/Plone*egg

Because Zope 2 will automatically scan all packages inside Products, there is no way to control exclusion of a Product in your instance. This is less than ideal. If our Product were not to use Zope2's Products namespace (which is well doable using Rocky Burt's pythonproducts), we could have more control of what is included, using Five's new registerPackage directive. (Note that pythonproducts was merged into Five.)

Now that all packages in Plone use the Products namespace, we'll have to think about a way to deal with this. Fortunately, easy_install comes with the --multi-version command line option, which allows you to have more control over which packages are available at runtime.

Using --multi-version, we can install our egg into the instance's lib/python directory to effectively make our egg only available in that instance:

easy_install --multi-version \
             --install-dir=$INSTANCE_HOME/lib/python/ \
             --site-dirs=$INSTANCE_HOME/lib/python/ \
             dist/Plone*egg

When you install something --multi-version, client code that uses your package has to be aware of that and do an explicit import pkg_resources; pkg_resources.require(name). In our example, we need to require('Plone') somewhen in our Zope process. I had the idea of requiring packages in zcml, similiar to how pythonproducts registers ordinary Python packages as Products. There's a pending patch for pythonproducts that enables this, although pythonproducts is maybe the wrong place to implement this:

Index: src/pythonproducts/fivedirectives.py
===================================================================
--- src/pythonproducts/fivedirectives.py      (revision 26757)
+++ src/pythonproducts/fivedirectives.py      (working copy)
@@ -16,6 +16,7 @@
 """

 from zope.interface import Interface
+from zope.schema import BytesLine
 from zope.configuration.fields import GlobalObject


@@ -35,4 +36,11 @@
                     u'with a ProductContext instance',
         required=False
         )
-
\ No newline at end of file
+
+class IRequireDistributionDirective(Interface):
+    """pkg_resources.require() a distribution."""
+
+    name = BytesLine(
+        title=u'Target distribution',
+        required=True,
+        )
Index: src/pythonproducts/meta.zcml
===================================================================
--- src/pythonproducts/meta.zcml      (revision 26757)
+++ src/pythonproducts/meta.zcml      (working copy)
@@ -12,6 +12,12 @@
        handler="Products.pythonproducts.pythonproducts.registerPackage"
        />

+    <meta:directive
+       name="requireDistribution"
+       schema="Products.pythonproducts.fivedirectives.IRequireDistributionDirective"
+       handler="Products.pythonproducts.pythonproducts.requireDistribution"
+       />
+
   </meta:directives>

 </configure>
Index: src/pythonproducts/pythonproducts.py
===================================================================
--- src/pythonproducts/pythonproducts.py      (revision 26757)
+++ src/pythonproducts/pythonproducts.py      (working copy)
@@ -37,6 +37,13 @@
         args = (package,initialize)
         )

+def requireDistribution(_context, name):
+    """ZCML directive function for requiring a distribution using
+    pkg_resources.
+    """
+
+    import pkg_resources
+    pkg_resources.require(name)

 def _registerPackage(module_, initFunc=None):
     """Registers the given python package as a Zope 2 style product

After applying this patch to your pythonproducts installation, you can go ahead and include Plone in your instance using zcml. Create a $INSTANCE_HOME/etc/package-includes/plone-configure.zcml file and put the following in it:

<configure xmlns="http://namespaces.zope.org/zope"
           xmlns:five="http://namespaces.zope.org/five">
    <five:requireDistribution name="Plone" />
</configure>

Please refer to the pythonproducts README for details on where to add zcml and why.

Now start up your Zope and hopefully see Plone getting loaded.

Note that for packages which are not in the Products namespace package, i.e. for Product-less Python packages you would need to use pythonproducts' registerPackage directive as well. (Which is a good thing.) For these packages, the whole process becomes a lot easier, because you can just easy_install away and be done, or if you need instance- specific versions/packages, use --multi-version and the requireDistribution directive.