Plugin

Complexity

Total Complexity

4

Size/Duplication

Total Lines	33
Duplicated Lines	0 %

Importance

Changes	1
Bugs	1	Features	0

4 Methods

Rating	Name	Duplication	Size	Complexity
A	onstart()	0	3	1
A	onreload()	0	3	1
A	onstop()	0	3	1
A	__init__()	0	10	1

# -*- coding: utf-8 -*-
"""Abstract classes that define the reader and writer plugin base classes.

.. moduleauthor:: Kenny Freeman <kenny.freeman@gmail.com>

"""
__author__ = 'Kenny Freeman'
__email__ = 'kenny.freeman@gmail.com'
__license__ = "ISCL"
__docformat__ = 'reStructuredText'

from abc import ABCMeta, abstractmethod


class Plugin(object):
    """The base class for all plugins.

    :param config: an instance of plumd.conf configuration helper
    :type config: conf
    """
    defaults = {}

    def __init__(self, log, config):
        """reader abstract class constructor - each plugin must sub class.

        :param config: an instance of plumd.conf configuration helper
        :type config: conf
        """
        self.config = config
        self.log = log
        # plugins can set their own defaults byt defining self.defaults
        self.config.defaults(self.defaults)


    def onstart(self):
        """onstart() is called before the first call to push()."""
        pass


    def onstop(self):
        """onstop() is called just before the main process exits."""
        pass


    def onreload(self):
        """onreload() is called to reload configuration at runtime."""
        raise NotImplementedError("todo")


class Reader(Plugin):
    """An abstract base class that all writer pluguns subclass."""
    __metaclass__ = ABCMeta

    @abstractmethod
    def poll(self):
        """Reader plugins must define this method, it measures and returns a
        metrics string.

        format <name:str> <value:float|int> <timestamp:time.time()>\n[...]
        set to change to a python object.

        :rtype: str
        """
        # this will never get called
        raise NotImplementedError("poll() not defined")


class Writer(Plugin):
    """An abstract base class that all writer pluguns subclass."""
    __metaclass__ = ABCMeta

    @abstractmethod
    def push(self, metrics):
        """Writer plugins must define this method, it accepts a metrics string
        and sends to its backend(s).

        :param metrics: metrics collection from reader poll() call.

        :type metrics: str
        """
        # this will never get called
        raise NotImplementedError("push() not defined")