"""
Plugin Manager
--------------
A plugin manager class is used to load plugins, manage the list of
loaded plugins, and proxy calls to those plugins.
The plugin managers provided with nose are:
:class:`PluginManager`
This manager doesn't implement loadPlugins, so it can only work
with a static list of plugins.
:class:`BuiltinPluginManager`
This manager loads plugins referenced in ``nose.plugins.builtin``.
:class:`EntryPointPluginManager`
This manager uses setuptools entrypoints to load plugins.
:class:`ExtraPluginsPluginManager`
This manager loads extra plugins specified with the keyword
`addplugins`.
:class:`DefaultPluginMananger`
This is the manager class that will be used by default. If
setuptools is installed, it is a subclass of
:class:`EntryPointPluginManager` and :class:`BuiltinPluginManager`;
otherwise, an alias to :class:`BuiltinPluginManager`.
:class:`RestrictedPluginManager`
This manager is for use in test runs where some plugin calls are
not available, such as runs started with ``python setup.py test``,
where the test runner is the default unittest :class:`TextTestRunner`. It
is a subclass of :class:`DefaultPluginManager`.
Writing a plugin manager
========================
If you want to load plugins via some other means, you can write a
plugin manager and pass an instance of your plugin manager class when
instantiating the :class:`nose.config.Config` instance that you pass to
:class:`TestProgram` (or :func:`main` or :func:`run`).
To implement your plugin loading scheme, implement ``loadPlugins()``,
and in that method, call ``addPlugin()`` with an instance of each plugin
you wish to make available. Make sure to call
``super(self).loadPlugins()`` as well if have subclassed a manager
other than ``PluginManager``.
"""
import inspect
import logging
import os
import sys
from itertools import chain as iterchain
from warnings import warn
import nose.config
from nose.failure import Failure
from nose.plugins.base import IPluginInterface
from nose.pyversion import sort_list
try:
import cPickle as pickle
except:
import pickle
try:
from cStringIO import StringIO
except:
from StringIO import StringIO
__all__ = ['DefaultPluginManager', 'PluginManager', 'EntryPointPluginManager',
'BuiltinPluginManager', 'RestrictedPluginManager']
log = logging.getLogger(__name__)
class PluginProxy(object):
"""Proxy for plugin calls. Essentially a closure bound to the
given call and plugin list.
The plugin proxy also must be bound to a particular plugin
interface specification, so that it knows what calls are available
and any special handling that is required for each call.
"""
interface = IPluginInterface
def __init__(self, call, plugins):
try:
self.method = getattr(self.interface, call)
except AttributeError:
raise AttributeError("%s is not a valid %s method"
% (call, self.interface.__name__))
self.call = self.makeCall(call)
self.plugins = []
for p in plugins:
self.addPlugin(p, call)
def __call__(self, *arg, **kw):
return self.call(*arg, **kw)
def addPlugin(self, plugin, call):
"""Add plugin to my list of plugins to call, if it has the attribute
I'm bound to.
"""
meth = getattr(plugin, call, None)
if meth is not None:
if call == 'loadTestsFromModule' and \
len(inspect.getargspec(meth)[0]) == 2:
orig_meth = meth
meth = lambda module, path, **kwargs: orig_meth(module)
self.plugins.append((plugin, meth))
def makeCall(self, call):
if call == 'loadTestsFromNames':
# special case -- load tests from names behaves somewhat differently
# from other chainable calls, because plugins return a tuple, only
# part of which can be chained to the next plugin.
return self._loadTestsFromNames
meth = self.method
if getattr(meth, 'generative', False):
# call all plugins and yield a flattened iterator of their results
return lambda *arg, **kw: list(self.generate(*arg, **kw))
elif getattr(meth, 'chainable', False):
return self.chain
else:
# return a value from the first plugin that returns non-None
return self.simple
def chain(self, *arg, **kw):
"""Call plugins in a chain, where the result of each plugin call is
sent to the next plugin as input. The final output result is returned.
"""
result = None
# extract the static arguments (if any) from arg so they can
# be passed to each plugin call in the chain
static = [a for (static, a)
in zip(getattr(self.method, 'static_args', []), arg)
if static]
for p, meth in self.plugins:
result = meth(*arg, **kw)
arg = static[:]
arg.append(result)
return result
def generate(self, *arg, **kw):
"""Call all plugins, yielding each item in each non-None result.
"""
for p, meth in self.plugins:
result = None
try:
result = meth(*arg, **kw)
if result is not None:
for r in result:
yield r
except (KeyboardInterrupt, SystemExit):
raise
except:
exc = sys.exc_info()
yield Failure(*exc)
continue
def simple(self, *arg, **kw):
"""Call all plugins, returning the first non-None result.
"""
for p, meth in self.plugins:
result = meth(*arg, **kw)
if result is not None:
return result
def _loadTestsFromNames(self, names, module=None):
"""Chainable but not quite normal. Plugins return a tuple of
(tests, names) after processing the names. The tests are added
to a suite that is accumulated throughout the full call, while
names are input for the next plugin in the chain.
"""
suite = []
for p, meth in self.plugins:
result = meth(names, module=module)
if result is not None:
suite_part, names = result
if suite_part:
suite.extend(suite_part)
return suite, names
class NoPlugins(object):
"""Null Plugin manager that has no plugins."""
interface = IPluginInterface
def __init__(self):
self._plugins = self.plugins = ()
def __iter__(self):
return ()
def _doNothing(self, *args, **kwds):
pass
def _emptyIterator(self, *args, **kwds):
return ()
def __getattr__(self, call):
method = getattr(self.interface, call)
if getattr(method, "generative", False):
return self._emptyIterator
else:
return self._doNothing
def addPlugin(self, plug):
raise NotImplementedError()
def addPlugins(self, plugins):
raise NotImplementedError()
def configure(self, options, config):
pass
def loadPlugins(self):
pass
def sort(self):
pass
class PluginManager(object):
"""Base class for plugin managers. PluginManager is intended to be
used only with a static list of plugins. The loadPlugins() implementation
only reloads plugins from _extraplugins to prevent those from being
overridden by a subclass.
The basic functionality of a plugin manager is to proxy all unknown
attributes through a ``PluginProxy`` to a list of plugins.
Note that the list of plugins *may not* be changed after the first plugin
call.
"""
proxyClass = PluginProxy
def __init__(self, plugins=(), proxyClass=None):
self._plugins = []
self._extraplugins = ()
self._proxies = {}
if plugins:
self.addPlugins(plugins)
if proxyClass is not None:
self.proxyClass = proxyClass
def __getattr__(self, call):
try:
return self._proxies[call]
except KeyError:
proxy = self.proxyClass(call, self._plugins)
self._proxies[call] = proxy
return proxy
def __iter__(self):
return iter(self.plugins)
def addPlugin(self, plug):
# allow, for instance, plugins loaded via entry points to
# supplant builtin plugins.
new_name = getattr(plug, 'name', object())
self._plugins[:] = [p for p in self._plugins
if getattr(p, 'name', None) != new_name]
self._plugins.append(plug)
def addPlugins(self, plugins=(), extraplugins=()):
"""extraplugins are maintained in a separate list and
re-added by loadPlugins() to prevent their being overwritten
by plugins added by a subclass of PluginManager
"""
self._extraplugins = extraplugins
for plug in iterchain(plugins, extraplugins):
self.addPlugin(plug)
def configure(self, options, config):
"""Configure the set of plugins with the given options
and config instance. After configuration, disabled plugins
are removed from the plugins list.
"""
log.debug("Configuring plugins")
self.config = config
cfg = PluginProxy('configure', self._plugins)
cfg(options, config)
enabled = [plug for plug in self._plugins if plug.enabled]
self.plugins = enabled
self.sort()
log.debug("Plugins enabled: %s", enabled)
def loadPlugins(self):
for plug in self._extraplugins:
self.addPlugin(plug)
def sort(self):
return sort_list(self._plugins, lambda x: getattr(x, 'score', 1), reverse=True)
def _get_plugins(self):
return self._plugins
def _set_plugins(self, plugins):
self._plugins = []
self.addPlugins(plugins)
plugins = property(_get_plugins, _set_plugins, None,
"""Access the list of plugins managed by
this plugin manager""")
class ZeroNinePlugin:
"""Proxy for 0.9 plugins, adapts 0.10 calls to 0.9 standard.
"""
def __init__(self, plugin):
self.plugin = plugin
def options(self, parser, env=os.environ):
self.plugin.add_options(parser, env)
def addError(self, test, err):
if not hasattr(self.plugin, 'addError'):
return
# switch off to addSkip, addDeprecated if those types
from nose.exc import SkipTest, DeprecatedTest
ec, ev, tb = err
if issubclass(ec, SkipTest):
if not hasattr(self.plugin, 'addSkip'):
return
return self.plugin.addSkip(test.test)
elif issubclass(ec, DeprecatedTest):
if not hasattr(self.plugin, 'addDeprecated'):
return
return self.plugin.addDeprecated(test.test)
# add capt
capt = test.capturedOutput
return self.plugin.addError(test.test, err, capt)
def loadTestsFromFile(self, filename):
if hasattr(self.plugin, 'loadTestsFromPath'):
return self.plugin.loadTestsFromPath(filename)
def addFailure(self, test, err):
if not hasattr(self.plugin, 'addFailure'):
return
# add capt and tbinfo
capt = test.capturedOutput
tbinfo = test.tbinfo
return self.plugin.addFailure(test.test, err, capt, tbinfo)
def addSuccess(self, test):
if not hasattr(self.plugin, 'addSuccess'):
return
capt = test.capturedOutput
self.plugin.addSuccess(test.test, capt)
def startTest(self, test):
if not hasattr(self.plugin, 'startTest'):
return
return self.plugin.startTest(test.test)
def stopTest(self, test):
if not hasattr(self.plugin, 'stopTest'):
return
return self.plugin.stopTest(test.test)
def __getattr__(self, val):
return getattr(self.plugin, val)
class EntryPointPluginManager(PluginManager):
"""Plugin manager that loads plugins from the `nose.plugins` and
`nose.plugins.0.10` entry points.
"""
entry_points = (('nose.plugins.0.10', None),
('nose.plugins', ZeroNinePlugin))
def loadPlugins(self):
"""Load plugins by iterating the `nose.plugins` entry point.
"""
from pkg_resources import iter_entry_points
loaded = {}
for entry_point, adapt in self.entry_points:
for ep in iter_entry_points(entry_point):
if ep.name in loaded:
continue
loaded[ep.name] = True
log.debug('%s load plugin %s', self.__class__.__name__, ep)
try:
plugcls = ep.load()
except KeyboardInterrupt:
raise
except Exception, e:
# never want a plugin load to kill the test run
# but we can't log here because the logger is not yet
# configured
warn("Unable to load plugin %s: %s" % (ep, e),
RuntimeWarning)
continue
if adapt:
plug = adapt(plugcls())
else:
plug = plugcls()
self.addPlugin(plug)
super(EntryPointPluginManager, self).loadPlugins()
class BuiltinPluginManager(PluginManager):
"""Plugin manager that loads plugins from the list in
`nose.plugins.builtin`.
"""
def loadPlugins(self):
"""Load plugins in nose.plugins.builtin
"""
from nose.plugins import builtin
for plug in builtin.plugins:
self.addPlugin(plug())
super(BuiltinPluginManager, self).loadPlugins()
try:
import pkg_resources
class DefaultPluginManager(EntryPointPluginManager, BuiltinPluginManager):
pass
except ImportError:
class DefaultPluginManager(BuiltinPluginManager):
pass
class RestrictedPluginManager(DefaultPluginManager):
"""Plugin manager that restricts the plugin list to those not
excluded by a list of exclude methods. Any plugin that implements
an excluded method will be removed from the manager's plugin list
after plugins are loaded.
"""
def __init__(self, plugins=(), exclude=(), load=True):
DefaultPluginManager.__init__(self, plugins)
self.load = load
self.exclude = exclude
self.excluded = []
self._excludedOpts = None
def excludedOption(self, name):
if self._excludedOpts is None:
from optparse import OptionParser
self._excludedOpts = OptionParser(add_help_option=False)
for plugin in self.excluded:
plugin.options(self._excludedOpts, env={})
return self._excludedOpts.get_option('--' + name)
def loadPlugins(self):
if self.load:
DefaultPluginManager.loadPlugins(self)
allow = []
for plugin in self.plugins:
ok = True
for method in self.exclude:
if hasattr(plugin, method):
ok = False
self.excluded.append(plugin)
break
if ok:
allow.append(plugin)
self.plugins = allow
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