Recipe for setting up a filestorage

This recipe can be used to define a file-storage. It creates a ZConfig file-storage database specification that can be used by other recipes to generate ZConfig configuration files.

This recipe takes an optional path option. If none is given, it creates and uses a subdirectory of the buildout parts directory with the same name as the part.

The recipe records a zconfig option for use by other recipes.

We'll show a couple of examples, using a dictionary as a simulated buildout object:

>>> import zc.recipe.filestorage
>>> buildout = dict(
...   buildout = {
...      'directory': '/buildout',
...      },
...   db = {
...      'path': 'foo/Main.fs',
...      },
...   )
>>> recipe = zc.recipe.filestorage.Recipe(
...                   buildout, 'db', buildout['db'])

>>> print(buildout['db']['path'])
/buildout/foo/Main.fs

>>> from six import print_
>>> print_(buildout['db']['zconfig'], end='')
<zodb>
  <filestorage>
    path /buildout/foo/Main.fs
  </filestorage>
</zodb>

>>> recipe.install()
()

>>> import tempfile
>>> d = tempfile.mkdtemp()
>>> buildout = dict(
...   buildout = {
...      'parts-directory': d,
...      },
...   db = {},
...   )

>>> recipe = zc.recipe.filestorage.Recipe(
...                   buildout, 'db', buildout['db'])

>>> print(buildout['db']['path'])
/tmp/tmpQo0DTB/db/Data.fs

>>> print_(buildout['db']['zconfig'], end='')
<zodb>
  <filestorage>
    path /tmp/tmpQo0DTB/db/Data.fs
  </filestorage>
</zodb>

>>> recipe.install()
()

>>> import os
>>> os.listdir(d)
['db']

The update method doesn't do much, as the database part's directory already exists, but it is present, so buildout doesn't complain and doesn't accidentally run install() again:

>>> recipe.update()

If the storage's directory is removed, is it re-added by the update method:

>>> os.rmdir(os.path.join(d, 'db'))
>>> os.listdir(d)
[]
>>> recipe.update()
>>> os.listdir(d)
['db']

This is useful in development when the directory containing the database is removed in order to start the database from scratch.