osm_lcm/lcm_hc.py

   1 #!/usr/bin/python3
   2 # -*- coding: utf-8 -*-
   3
   4 ##
   5 # Copyright 2018 Telefonica S.A.
   6 #
   7 # Licensed under the Apache License, Version 2.0 (the "License"); you may
   8 # not use this file except in compliance with the License. You may obtain
   9 # a copy of the License at
  10 #
  11 #         http://www.apache.org/licenses/LICENSE-2.0
  12 #
  13 # Unless required by applicable law or agreed to in writing, software
  14 # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  15 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  16 # License for the specific language governing permissions and limitations
  17 # under the License.
  18 ##
  19
  20 from time import time, sleep
  21 from sys import stderr
  22
  23 from osm_lcm.lcm_utils import LcmException
  24 import yaml
  25
  26 """ This module is used for health check. A file called time_last_ping is used
  27 This contains the last time where something is received from kafka
  28 """
  29
  30
  31 def get_health_check_file(config_file=None):
  32     try:
  33         health_check_file = "/app/storage/time_last_ping"
  34         if not config_file:
  35             return health_check_file
  36         # If config_input is dictionary
  37         if isinstance(config_file, dict) and config_file.get("storage"):
  38             health_check_file = config_file["storage"]["path"] + "/time_last_ping"
  39         # If config_input is file
  40         elif isinstance(config_file, str):
  41             with open(config_file) as f:
  42                 # read file as yaml format
  43                 conf = yaml.safe_load(f)
  44                 # Ensure all sections are not empty
  45                 if conf.get("storage"):
  46                     health_check_file = conf["storage"]["path"] + "/time_last_ping"
  47
  48         return health_check_file
  49     except (IOError, FileNotFoundError, TypeError, AttributeError, KeyError) as error:
  50         raise LcmException(
  51             f"Error occured while getting the health check file location: {error}"
  52         )
  53
  54
  55 def health_check(config_file=None, ping_interval_pace=120):
  56     health_check_file = get_health_check_file(config_file)
  57     retry = 2
  58     while retry:
  59         retry -= 1
  60         try:
  61             with open(health_check_file, "r") as f:
  62                 last_received_ping = f.read()
  63
  64             if (
  65                 time() - float(last_received_ping) < 2 * ping_interval_pace
  66             ):  # allow one ping not received every two
  67                 exit(0)
  68         except Exception as e:
  69             print(e, file=stderr)
  70         if retry:
  71             sleep(6)
  72     exit(1)
  73
  74
  75 if __name__ == "__main__":
  76     health_check()