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     def __init__(self, config: Config):
  39         super().__init__(config)
  40         self.conf = config
  41
  42     def get_metric_value(self, metric_name: str, tags: dict):
  43         query = self._build_query(metric_name, tags)
  44         request_url = self._build_url(query)
  45         request_headers = self._build_headers()
  46         return self._query_metric(request_url, request_headers)
  47
  48     def _query_metric(self, request_url: str, headers: Dict[str, str]):
  49         log.info("Querying Prometheus: %s", request_url)
  50         r = requests.get(
  51             request_url,
  52             timeout=int(self.conf.get("global", "request_timeout")),
  53             headers=headers,
  54         )
  55         if r.status_code == 200:
  56             json_response = r.json()
  57             if json_response["status"] == "success":
  58                 return self._get_metric_value_from_response(json_response)
  59             else:
  60                 log.warning(
  61                     "Prometheus response is not success. Got status %s",
  62                     json_response["status"],
  63                 )
  64         else:
  65             log.warning(
  66                 "Error contacting Prometheus. Got status code %s: %s",
  67                 r.status_code,
  68                 r.text,
  69             )
  70         return None
  71
  72     def _build_query(self, metric_name: str, tags: dict) -> str:
  73         query_section_tags = []
  74         for k, v in tags.items():
  75             query_section_tags.append(k + '="' + v + '"')
  76         query_section = "query={0}{{{1}}}".format(
  77             OSM_METRIC_PREFIX + metric_name, ",".join(query_section_tags)
  78         )
  79         return query_section
  80
  81     def _build_url(self, query: str):
  82         return self.conf.get("prometheus", "url") + "/api/v1/query?" + query
  83
  84     def _build_headers(self) -> Dict[str, str]:
  85         headers = {}
  86         user = self.conf.get("prometheus", "user")
  87         password = self.conf.get("prometheus", "password")
  88         if user and password:
  89             _phrase = f"{user}:{password}".encode("utf-8")
  90             token = base64.b64encode(_phrase).decode("utf-8")
  91             headers["Authorization"] = f"Basic {token}"
  92         return headers
  93
  94     def _get_metric_value_from_response(self, json_response):
  95         result = json_response["data"]["result"]
  96         if len(result):
  97             metric_value = float(result[0]["value"][1])
  98             log.info("Metric value: %s", metric_value)
  99             return metric_value
 100         else:
 101             return None