python.d/python_modules/base.py

   1 # -*- coding: utf-8 -*-
   2 # Description: base for netdata python.d plugins
   3 # Author: Pawel Krupa (paulfantom)
   4
   5 from time import time
   6 import sys
   7
   8
   9 class BaseService(object):
  10     """
  11     Prototype of Service class.
  12     Implemented basic functionality to run jobs by `python.d.plugin`
  13     """
  14     def __init__(self, configuration=None, name=None):
  15         """
  16         This needs to be initialized in child classes
  17         :param configuration: dict
  18         :param name: str
  19         """
  20         self.name = name
  21         if configuration is None:
  22             self.error("BaseService: no configuration parameters supplied. Cannot create Service.")
  23             raise RuntimeError
  24         else:
  25             self._extract_base_config(configuration)
  26             self.timetable = {}
  27             self.create_timetable()
  28             self.chart_name = ""
  29
  30     def _extract_base_config(self, config):
  31         """
  32         Get basic parameters to run service
  33         Minimum config:
  34             config = {'update_every':1,
  35                       'priority':100000,
  36                       'retries':0}
  37         :param config: dict
  38         """
  39         self.update_every = int(config.pop('update_every'))
  40         self.priority = int(config.pop('priority'))
  41         self.retries = int(config.pop('retries'))
  42         self.retries_left = self.retries
  43         self.configuration = config
  44
  45     def create_timetable(self, freq=None):
  46         """
  47         Create service timetable.
  48         `freq` is optional
  49         Example:
  50             timetable = {'last': 1466370091.3767564,
  51                          'next': 1466370092,
  52                          'freq': 1}
  53         :param freq: int
  54         """
  55         if freq is None:
  56             freq = self.update_every
  57         now = time()
  58         self.timetable = {'last': now,
  59                           'next': now - (now % freq) + freq,
  60                           'freq': freq}
  61
  62     @staticmethod
  63     def error(msg, exception=""):
  64         if exception != "":
  65             exception = " " + str(exception).replace("\n"," ")
  66         sys.stderr.write(str(msg)+exception+"\n")
  67         sys.stderr.flush()
  68
  69     def check(self):
  70         """
  71         check() prototype
  72         :return: boolean
  73         """
  74         self.error("Service " + str(self.__name__) + "doesn't implement check() function")
  75         return False
  76
  77     def create(self):
  78         """
  79         create() prototype
  80         :return: boolean
  81         """
  82         self.error("Service " + str(self.__name__) + "doesn't implement create() function?")
  83         return False
  84
  85     def update(self):
  86         """
  87         update() prototype
  88         :return: boolean
  89         """
  90         self.error("Service " + str(self.__name__) + "doesn't implement update() function")
  91         return False