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# -.- coding: utf-8 -.-
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# Copyright © 2009 Markus Korn <thekorn@gmx.de>
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# Copyright © 2009 Siegfried-Angel Gevatter Pujals <rainct@ubuntu.com>
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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# You should have received a copy of the GNU Lesser General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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from xdg import BaseDirectory
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logging.basicConfig(level=logging.DEBUG)
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log = logging.getLogger("zeitgeist.engine")
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DB_PATH = os.path.join(BaseDirectory.save_data_path("zeitgeist"),
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AVAILABLE_ENGINES = ["querymancer", "storm"]
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ENGINE_FALLBACK = AVAILABLE_ENGINES[0]
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def get_engine_type():
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""" Returns the value of the $ZEITGEIST_ENGINE environment variable or,
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if it isn't defined, the default engine."""
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value = os.environ.get("ZEITGEIST_ENGINE")
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if value == "default":
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if value and value.lower() not in AVAILABLE_ENGINES:
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raise RuntimeError("Unknown engine type requested: \"%s\"." % value)
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return value.lower() if value else ENGINE_FALLBACK
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def create_engine(engine_type=None):
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""" Creates an engine instance of the type defined by 'engine_type'.
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If 'engine_type' is None 'ENGINE_FALLBACK' is used.
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This function looks at _zeitgeist.engine to find the engine implementation.
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Each engine implementation has to follow the following conventions:
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1.) it has to be in _zeitgeist/engine/SOMENAME_engine.py
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(where SOMENAME defines the type)
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2.) the name of the class has to be ZeitgeistEngine and the class
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itself has to be a sublass of _zeitgeist.engine.engine_base.BaseEngine
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if engine_type is None:
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engine_type = ENGINE_FALLBACK
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engine_type = engine_type.lower()
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# See if we can reuse _engine
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if _engine and not _engine.is_closed():
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running_type = _engine.__module__.split(".").pop().lower()
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if not running_type == engine_type:
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("There is already a zeitgeist engine running. But this "
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"engine has another than the requested type "
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"(requested='%s', running='%s')" %(engine_type, running_type))
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log.debug("Creating engine '%s'" % engine_type)
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engine_cls = __import__(
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"_zeitgeist.engine.%s_engine" %engine_type,
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globals(), locals(), ["ZeitgeistEngine",], -1
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except ImportError, err:
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logging.exception("Could not load engine implementation for %r" % engine_type)
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_engine = engine_cls.ZeitgeistEngine()
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def get_default_engine():
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""" Get the running engine instance or create a new one. """
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if _engine is None or _engine.is_closed() :
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return create_engine(engine_type=get_engine_type())
added
removed
_zeitgeist/engine/__init__.py
