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['update_every'])
  40         self.priority = int(config['priority'])
  41         self.retries = int(config['retries'])
  42         self.retries_left = self.retries
  43
  44     def create_timetable(self, freq=None):
  45         """
  46         Create service timetable.
  47         `freq` is optional
  48         Example:
  49             timetable = {'last': 1466370091.3767564,
  50                          'next': 1466370092,
  51                          'freq': 1}
  52         :param freq: int
  53         """
  54         if freq is None:
  55             freq = self.update_every
  56         now = time()
  57         self.timetable = {'last': now,
  58                           'next': now - (now % freq) + freq,
  59                           'freq': freq}
  60
  61     @staticmethod
  62     def error(msg, exception=""):
  63         if exception != "":
  64             exception = " " + str(exception).replace("\n"," ")
  65         sys.stderr.write(str(msg)+exception+"\n")
  66         sys.stderr.flush()
  67
  68     def check(self):
  69         """
  70         check() prototype
  71         :return: boolean
  72         """
  73         self.error("Service " + str(self.__name__) + "doesn't implement check() function")
  74         return False
  75
  76     def create(self):
  77         """
  78         create() prototype
  79         :return: boolean
  80         """
  81         self.error("Service " + str(self.__name__) + "doesn't implement create() function?")
  82         return False
  83
  84     def update(self):
  85         """
  86         update() prototype
  87         :return: boolean
  88         """
  89         self.error("Service " + str(self.__name__) + "doesn't implement update() function")
  90         return False