osm_mon/evaluator/backends/prometheus.py

   1 # -*- coding: utf-8 -*-
   2
   3 # Copyright 2018 Whitestack, LLC
   4 # *************************************************************
   5
   6 # This file is part of OSM Monitoring module
   7 # All Rights Reserved to Whitestack, LLC
   8
   9 # Licensed under the Apache License, Version 2.0 (the "License"); you may
  10 # not use this file except in compliance with the License. You may obtain
  11 # a copy of the License at
  12
  13 #         http://www.apache.org/licenses/LICENSE-2.0
  14
  15 # Unless required by applicable law or agreed to in writing, software
  16 # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  17 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  18 # License for the specific language governing permissions and limitations
  19 # under the License.
  20 # For those usages not covered by the Apache License, Version 2.0 please
  21 # contact: bdiaz@whitestack.com or glavado@whitestack.com
  22 ##
  23 import base64
  24 import logging
  25 from typing import Dict
  26
  27 import requests
  28
  29 from osm_mon.core.config import Config
  30 from osm_mon.evaluator.backends.base import BaseBackend
  31
  32 log = logging.getLogger(__name__)
  33
  34 OSM_METRIC_PREFIX = 'osm_'
  35
  36
  37 class PrometheusBackend(BaseBackend):
  38
  39     def __init__(self, config: Config):
  40         super().__init__(config)
  41         self.conf = config
  42
  43     def get_metric_value(self, metric_name: str, tags: dict):
  44         query = self._build_query(metric_name, tags)
  45         request_url = self._build_url(query)
  46         request_headers = self._build_headers()
  47         return self._query_metric(request_url, request_headers)
  48
  49     def _query_metric(self, request_url: str, headers: Dict[str, str]):
  50         log.info("Querying Prometheus: %s", request_url)
  51         r = requests.get(
  52             request_url,
  53             timeout=int(self.conf.get("global", "request_timeout")),
  54             headers=headers,
  55         )
  56         if r.status_code == 200:
  57             json_response = r.json()
  58             if json_response['status'] == 'success':
  59                 return self._get_metric_value_from_response(json_response)
  60             else:
  61                 log.warning("Prometheus response is not success. Got status %s", json_response['status'])
  62         else:
  63             log.warning("Error contacting Prometheus. Got status code %s: %s", r.status_code, r.text)
  64         return None
  65
  66     def _build_query(self, metric_name: str, tags: dict) -> str:
  67         query_section_tags = []
  68         for k, v in tags.items():
  69             query_section_tags.append(k + '=\"' + v + '\"')
  70         query_section = "query={0}{{{1}}}".format(OSM_METRIC_PREFIX + metric_name, ','.join(query_section_tags))
  71         return query_section
  72
  73     def _build_url(self, query: str):
  74         return self.conf.get('prometheus', 'url') + "/api/v1/query?" + query
  75
  76     def _build_headers(self) -> Dict[str, str]:
  77         headers = {}
  78         user = self.conf.get("prometheus", "user")
  79         password = self.conf.get("prometheus", "password")
  80         if user and password:
  81             _phrase = f"{user}:{password}".encode("utf-8")
  82             token = base64.b64encode(_phrase).decode("utf-8")
  83             headers["Authorization"] = f"Basic {token}"
  84         return headers
  85
  86     def _get_metric_value_from_response(self, json_response):
  87         result = json_response['data']['result']
  88         if len(result):
  89             metric_value = float(result[0]['value'][1])
  90             log.info("Metric value: %s", metric_value)
  91             return metric_value
  92         else:
  93             return None