D7net
Home
Console
Upload
information
Create File
Create Folder
About
Tools
:
/
proc
/
2
/
task
/
2
/
root
/
opt
/
imh-python
/
lib
/
python2.7
/
site-packages
/
stevedore
/
Filename :
dispatch.py
back
Copy
import logging from .enabled import EnabledExtensionManager from .exception import NoMatches LOG = logging.getLogger(__name__) class DispatchExtensionManager(EnabledExtensionManager): """Loads all plugins and filters on execution. This is useful for long-running processes that need to pass different inputs to different extensions. :param namespace: The namespace for the entry points. :type namespace: str :param check_func: Function to determine which extensions to load. :type check_func: callable :param invoke_on_load: Boolean controlling whether to invoke the object returned by the entry point after the driver is loaded. :type invoke_on_load: bool :param invoke_args: Positional arguments to pass when invoking the object returned by the entry point. Only used if invoke_on_load is True. :type invoke_args: tuple :param invoke_kwds: Named arguments to pass when invoking the object returned by the entry point. Only used if invoke_on_load is True. :type invoke_kwds: dict :param propagate_map_exceptions: Boolean controlling whether exceptions are propagated up through the map call or whether they are logged and then ignored :type invoke_on_load: bool """ def map(self, filter_func, func, *args, **kwds): """Iterate over the extensions invoking func() for any where filter_func() returns True. The signature of filter_func() should be:: def filter_func(ext, *args, **kwds): pass The first argument to filter_func(), 'ext', is the :class:`~stevedore.extension.Extension` instance. filter_func() should return True if the extension should be invoked for the input arguments. The signature for func() should be:: def func(ext, *args, **kwds): pass The first argument to func(), 'ext', is the :class:`~stevedore.extension.Extension` instance. Exceptions raised from within func() are propagated up and processing stopped if self.propagate_map_exceptions is True, otherwise they are logged and ignored. :param filter_func: Callable to test each extension. :param func: Callable to invoke for each extension. :param args: Variable arguments to pass to func() :param kwds: Keyword arguments to pass to func() :returns: List of values returned from func() """ if not self.extensions: # FIXME: Use a more specific exception class here. raise NoMatches('No %s extensions found' % self.namespace) response = [] for e in self.extensions: if filter_func(e, *args, **kwds): self._invoke_one_plugin(response.append, func, e, args, kwds) return response def map_method(self, filter_func, method_name, *args, **kwds): """Iterate over the extensions invoking each one's object method called `method_name` for any where filter_func() returns True. This is equivalent of using :meth:`map` with func set to `lambda x: x.obj.method_name()` while being more convenient. Exceptions raised from within the called method are propagated up and processing stopped if self.propagate_map_exceptions is True, otherwise they are logged and ignored. .. versionadded:: 0.12 :param filter_func: Callable to test each extension. :param method_name: The extension method name to call for each extension. :param args: Variable arguments to pass to method :param kwds: Keyword arguments to pass to method :returns: List of values returned from methods """ return self.map(filter_func, self._call_extension_method, method_name, *args, **kwds) class NameDispatchExtensionManager(DispatchExtensionManager): """Loads all plugins and filters on execution. This is useful for long-running processes that need to pass different inputs to different extensions and can predict the name of the extensions before calling them. The check_func argument should return a boolean, with ``True`` indicating that the extension should be loaded and made available and ``False`` indicating that the extension should be ignored. :param namespace: The namespace for the entry points. :type namespace: str :param check_func: Function to determine which extensions to load. :type check_func: callable :param invoke_on_load: Boolean controlling whether to invoke the object returned by the entry point after the driver is loaded. :type invoke_on_load: bool :param invoke_args: Positional arguments to pass when invoking the object returned by the entry point. Only used if invoke_on_load is True. :type invoke_args: tuple :param invoke_kwds: Named arguments to pass when invoking the object returned by the entry point. Only used if invoke_on_load is True. :type invoke_kwds: dict :param propagate_map_exceptions: Boolean controlling whether exceptions are propagated up through the map call or whether they are logged and then ignored :type invoke_on_load: bool :param on_load_failure_callback: Callback function that will be called when a entrypoint can not be loaded. The arguments that will be provided when this is called (when an entrypoint fails to load) are (manager, entrypoint, exception) :type on_load_failure_callback: function :param verify_requirements: Use setuptools to enforce the dependencies of the plugin(s) being loaded. Defaults to False. :type verify_requirements: bool """ def __init__(self, namespace, check_func, invoke_on_load=False, invoke_args=(), invoke_kwds={}, propagate_map_exceptions=False, on_load_failure_callback=None, verify_requirements=False): super(NameDispatchExtensionManager, self).__init__( namespace=namespace, check_func=check_func, invoke_on_load=invoke_on_load, invoke_args=invoke_args, invoke_kwds=invoke_kwds, propagate_map_exceptions=propagate_map_exceptions, on_load_failure_callback=on_load_failure_callback, verify_requirements=verify_requirements, ) def _init_plugins(self, extensions): super(NameDispatchExtensionManager, self)._init_plugins(extensions) self.by_name = dict((e.name, e) for e in self.extensions) def map(self, names, func, *args, **kwds): """Iterate over the extensions invoking func() for any where the name is in the given list of names. The signature for func() should be:: def func(ext, *args, **kwds): pass The first argument to func(), 'ext', is the :class:`~stevedore.extension.Extension` instance. Exceptions raised from within func() are propagated up and processing stopped if self.propagate_map_exceptions is True, otherwise they are logged and ignored. :param names: List or set of name(s) of extension(s) to invoke. :param func: Callable to invoke for each extension. :param args: Variable arguments to pass to func() :param kwds: Keyword arguments to pass to func() :returns: List of values returned from func() """ response = [] for name in names: try: e = self.by_name[name] except KeyError: LOG.debug('Missing extension %r being ignored', name) else: self._invoke_one_plugin(response.append, func, e, args, kwds) return response def map_method(self, names, method_name, *args, **kwds): """Iterate over the extensions invoking each one's object method called `method_name` for any where the name is in the given list of names. This is equivalent of using :meth:`map` with func set to `lambda x: x.obj.method_name()` while being more convenient. Exceptions raised from within the called method are propagated up and processing stopped if self.propagate_map_exceptions is True, otherwise they are logged and ignored. .. versionadded:: 0.12 :param names: List or set of name(s) of extension(s) to invoke. :param method_name: The extension method name to call for each extension. :param args: Variable arguments to pass to method :param kwds: Keyword arguments to pass to method :returns: List of values returned from methods """ return self.map(names, self._call_extension_method, method_name, *args, **kwds)