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# (C) Copyright 2007-2023 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!
""" A plugin manager that finds plugins in packages on the 'plugin_path'. """
import logging
import sys
import warnings
from apptools.io import File
from traits.api import Directory, List, on_trait_change
from .plugin_manager import PluginManager
logger = logging.getLogger(__name__)
class PackagePluginManager(PluginManager):
"""A plugin manager that finds plugins in packages on the 'plugin_path'.
All items in 'plugin_path' are directory names and they are all added to
'sys.path' (if not already present). Each directory is then searched for
plugins as follows:-
a) If the package contains a 'plugins.py' module, then we import it and
look for a callable 'get_plugins' that takes no arguments and returns
a list of plugins (i.e. instances that implement 'IPlugin'!).
b) If the package contains any modules named in the form 'xxx_plugin.py'
then the module is imported and if it contains a callable 'XXXPlugin' it is
called with no arguments and it must return a single plugin.
"""
def __init__(self, **traits):
warnings.warn(
(
"The PackagePluginManager is deprecated. The recommended "
"approach is to install plugin-containing packages into "
"site-packages and advertise the plugins via entry points. "
),
DeprecationWarning,
stacklevel=2,
)
super().__init__(**traits)
# Plugin manifest.
PLUGIN_MANIFEST = "plugins.py"
#### 'PackagePluginManager' protocol ######################################
# A list of directories that will be searched to find plugins.
plugin_path = List(Directory)
@on_trait_change("plugin_path[]")
def _update_path_and_reset_plugins(self, obj, trait_name, removed, added):
self._update_sys_dot_path(removed, added)
self.reset_traits(["_plugins"])
#### Protected 'PluginManager' protocol ###################################
def __plugins_default(self):
"""Trait initializer."""
plugins = [
plugin
for plugin in self._harvest_plugins_in_packages()
if self._include_plugin(plugin.id)
]
logger.debug("package plugin manager found plugins <%s>", plugins)
return plugins
#### Private protocol #####################################################
def _get_plugins_module(self, package_name):
"""Import 'plugins.py' from the package with the given name.
If the package does not exist, or does not contain 'plugins.py' then
return None.
"""
try:
module = __import__(
package_name + ".plugins", fromlist=["plugins"]
)
except ImportError:
module = None
return module
# smell: Looooong and ugly!
def _harvest_plugins_in_package(self, package_name, package_dirname):
"""Harvest plugins found in the given package."""
# If the package contains a 'plugins.py' module, then we import it and
# look for a callable 'get_plugins' that takes no arguments and returns
# a list of plugins (i.e. instances that implement 'IPlugin'!).
plugins_module = self._get_plugins_module(package_name)
if plugins_module is not None:
factory = getattr(plugins_module, "get_plugins", None)
if factory is not None:
plugins = factory()
# Otherwise, look for any modules in the form 'xxx_plugin.py' and
# see if they contain a callable in the form 'XXXPlugin' and if they
# do, call it with no arguments to get a plugin!
else:
plugins = []
logger.debug("Looking for plugins in %s" % package_dirname)
for child in File(package_dirname).children or []:
if child.ext == ".py" and child.name.endswith("_plugin"):
module = __import__(
package_name + "." + child.name, fromlist=[child.name]
)
atoms = child.name.split("_")
capitalized = [atom.capitalize() for atom in atoms]
factory_name = "".join(capitalized)
factory = getattr(module, factory_name, None)
if factory is not None:
plugins.append(factory())
return plugins
def _harvest_plugins_in_packages(self):
"""Harvest plugins found in packages on the plugin path."""
plugins = []
for dirname in self.plugin_path:
for child in File(dirname).children or []:
if child.is_package:
plugins.extend(
self._harvest_plugins_in_package(
child.name, child.path
)
)
return plugins
def _update_sys_dot_path(self, removed, added):
"""Add/remove the given entries from sys.path."""
for dirname in removed:
if dirname in sys.path:
sys.path.remove(dirname)
for dirname in added:
if dirname not in sys.path:
sys.path.append(dirname)
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