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# -*- coding: utf-8 -*- |
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"""Abstract classes that define the reader and writer plugin base classes. |
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.. moduleauthor:: Kenny Freeman <[email protected]> |
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""" |
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__author__ = 'Kenny Freeman' |
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__email__ = '[email protected]' |
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__license__ = "ISCL" |
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__docformat__ = 'reStructuredText' |
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from abc import ABCMeta, abstractmethod |
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class Plugin(object): |
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"""The base class for all plugins. |
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:param config: an instance of plumd.conf configuration helper |
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:type config: conf |
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""" |
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__metaclass__ = ABCMeta |
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defaults = {} |
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def __init__(self, log, config): |
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"""reader abstract class constructor - each plugin must sub class. |
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:param config: an instance of plumd.conf configuration helper |
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:type config: conf |
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""" |
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self.config = config |
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self.log = log |
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# plugins can set their own defaults byt defining self.defaults |
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self.config.defaults(self.defaults) |
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def __str__(self): |
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"""Return a human readable str. |
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:rtype: str""" |
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s = "Plugin(class={1})".format(self.__class__.__name__) |
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return s |
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def __repr__(self): |
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"""Return a human readable str. |
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:rtype: str""" |
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s = "Plugin(class={1})".format(self.__class__.__name__) |
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return s |
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def onstart(self): |
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"""onstart() is called before the first call to push().""" |
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self.log.debug("Plugin: onstart: {0}".format(self.config.get('name'))) |
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pass |
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def onstop(self): |
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"""onstop() is called just before the main process exits.""" |
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self.log.debug("Plugin: onstop: {0}".format(self.config.get('name'))) |
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pass |
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def onreload(self): |
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"""onreload() is called to reload configuration at runtime.""" |
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raise NotImplementedError("todo") |
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class Reader(Plugin): |
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"""An abstract base class that all writer pluguns subclass.""" |
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__metaclass__ = ABCMeta |
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@abstractmethod |
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def poll(self): |
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"""Reader plugins must define this method, it measures and returns a |
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metrics string. |
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format <name:str> <value:float|int> <timestamp:time.time()>\n[...] |
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set to change to a python object. |
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:rtype: str |
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""" |
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# this will never get called |
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raise NotImplementedError("poll() not defined") |
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class Writer(Plugin): |
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"""An abstract base class that all writer pluguns subclass.""" |
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__metaclass__ = ABCMeta |
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@abstractmethod |
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def push(self, metrics): |
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"""Writer plugins must define this method, it accepts a metrics string |
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and sends to its backend(s). |
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:param metrics: metrics collection from reader poll() call. |
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:type metrics: str |
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""" |
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# this will never get called |
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raise NotImplementedError("push() not defined") |
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