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Viewing changes to vendor/carrot/backends/__init__.py

  • Committer: Jesse Andrews
  • Date: 2010-05-28 06:05:26 UTC
  • Revision ID: git-v1:bf6e6e718cdc7488e2da87b21e258ccc065fe499
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vendor/carrot/backends/__init__.py
 
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"""
 
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Working with Backends.
 
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"""
 
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import sys
 
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from carrot.utils import rpartition
 
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DEFAULT_BACKEND = "carrot.backends.pyamqplib.Backend"
 
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BACKEND_ALIASES = {
 
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    "amqp": "carrot.backends.pyamqplib.Backend",
 
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    "amqplib": "carrot.backends.pyamqplib.Backend",
 
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    "stomp": "carrot.backends.pystomp.Backend",
 
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    "stompy": "carrot.backends.pystomp.Backend",
 
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    "memory": "carrot.backends.queue.Backend",
 
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    "mem": "carrot.backends.queue.Backend",
 
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    "pika": "carrot.backends.pikachu.AsyncoreBackend",
 
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    "pikachu": "carrot.backends.pikachu.AsyncoreBackend",
 
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    "syncpika": "carrot.backends.pikachu.SyncBackend",
 
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}
 
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_backend_cache = {}
 
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def resolve_backend(backend=None):
 
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    backend = BACKEND_ALIASES.get(backend, backend)
 
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    backend_module_name, _, backend_cls_name = rpartition(backend, ".")
 
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    return backend_module_name, backend_cls_name
 
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def _get_backend_cls(backend=None):
 
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    backend_module_name, backend_cls_name = resolve_backend(backend)
 
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    __import__(backend_module_name)
 
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    backend_module = sys.modules[backend_module_name]
 
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    return getattr(backend_module, backend_cls_name)
 
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def get_backend_cls(backend=None):
 
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    """Get backend class by name.
 
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    The backend string is the full path to a backend class, e.g.::
 
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        "carrot.backends.pyamqplib.Backend"
 
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    If the name does not include "``.``" (is not fully qualified),
 
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    the alias table will be consulted.
 
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    """
 
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    backend = backend or DEFAULT_BACKEND
 
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    if backend not in _backend_cache:
 
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        _backend_cache[backend] = _get_backend_cls(backend)
 
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    return _backend_cache[backend]