126 lines
4.7 KiB
Python
126 lines
4.7 KiB
Python
from .enabled import EnabledExtensionManager
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class DispatchExtensionManager(EnabledExtensionManager):
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"""Loads all plugins and filters on execution.
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This is useful for long-running processes that need to pass
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different inputs to different extensions.
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:param namespace: The namespace for the entry points.
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:type namespace: str
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:param check_func: Function to determine which extensions to load.
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:type check_func: callable
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:param invoke_on_load: Boolean controlling whether to invoke the
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object returned by the entry point after the driver is loaded.
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:type invoke_on_load: bool
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:param invoke_args: Positional arguments to pass when invoking
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the object returned by the entry point. Only used if invoke_on_load
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is True.
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:type invoke_args: tuple
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:param invoke_kwds: Named arguments to pass when invoking
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the object returned by the entry point. Only used if invoke_on_load
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is True.
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:type invoke_kwds: dict
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"""
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def map(self, filter_func, func, *args, **kwds):
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"""Iterate over the extensions invoking func() for any where
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filter_func() returns True.
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The signature of filter_func() should be::
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def filter_func(ext, *args, **kwds):
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pass
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The first argument to filter_func(), 'ext', is the
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:class:`~stevedore.extension.Extension`
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instance. filter_func() should return True if the extension
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should be invoked for the input arguments.
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The signature for func() should be::
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def func(ext, *args, **kwds):
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pass
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The first argument to func(), 'ext', is the
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:class:`~stevedore.extension.Extension` instance.
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Exceptions raised from within filter_func() and func() are
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logged and ignored.
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:param filter_func: Callable to test each extension.
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:param func: Callable to invoke for each extension.
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:param args: Variable arguments to pass to func()
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:param kwds: Keyword arguments to pass to func()
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:returns: List of values returned from func()
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"""
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if not self.extensions:
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# FIXME: Use a more specific exception class here.
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raise RuntimeError('No %s extensions found' % self.namespace)
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response = []
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for e in self.extensions:
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if filter_func(e, *args, **kwds):
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self._invoke_one_plugin(response.append, func, e, args, kwds)
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return response
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class NameDispatchExtensionManager(DispatchExtensionManager):
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"""Loads all plugins and filters on execution.
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This is useful for long-running processes that need to pass
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different inputs to different extensions and can predict the name
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of the extensions before calling them.
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:param namespace: The namespace for the entry points.
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:type namespace: str
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:param invoke_on_load: Boolean controlling whether to invoke the
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object returned by the entry point after the driver is loaded.
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:type invoke_on_load: bool
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:param invoke_args: Positional arguments to pass when invoking
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the object returned by the entry point. Only used if invoke_on_load
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is True.
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:type invoke_args: tuple
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:param invoke_kwds: Named arguments to pass when invoking
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the object returned by the entry point. Only used if invoke_on_load
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is True.
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:type invoke_kwds: dict
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"""
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def __init__(self, namespace, check_func, invoke_on_load=False,
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invoke_args=(), invoke_kwds={}):
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super(NameDispatchExtensionManager, self).__init__(
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namespace=namespace,
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check_func=check_func,
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invoke_on_load=invoke_on_load,
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invoke_args=invoke_args,
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invoke_kwds=invoke_kwds,
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)
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self.by_name = dict((e.name, e) for e in self.extensions)
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def map(self, names, func, *args, **kwds):
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"""Iterate over the extensions invoking func() for any where
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the name is in the given list of names.
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The signature for func() should be::
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def func(ext, *args, **kwds):
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pass
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The first argument to func(), 'ext', is the
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:class:`~stevedore.extension.Extension` instance.
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Exceptions raised from within func() are logged and ignored.
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:param names: List or set of name(s) of extension(s) to invoke.
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:param func: Callable to invoke for each extension.
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:param args: Variable arguments to pass to func()
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:param kwds: Keyword arguments to pass to func()
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:returns: List of values returned from func()
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"""
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response = []
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for name in names:
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e = self.by_name[name]
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self._invoke_one_plugin(response.append, func, e, args, kwds)
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return response
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