docker/Prometheus/src/app.py

   1 #!/usr/bin/env python
   2
   3 # Copyright 2021 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
  21 # For those usages not covered by the Apache License, Version 2.0 please
  22 # contact: fbravo@whitestack.com
  23 ##
  24
  25 import os
  26 import pymongo
  27 import yaml
  28 import aiohttp
  29 import asyncio
  30 import copy
  31 import json
  32 import time
  33 from bson.json_util import dumps
  34 from bson import ObjectId
  35
  36 # Env variables
  37 mongodb_url = os.environ["MONGODB_URL"]
  38 target_database = os.environ["TARGET_DATABASE"]
  39 prometheus_config_file = os.environ["PROMETHEUS_CONFIG_FILE"]
  40 prometheus_base_config_file = os.environ["PROMETHEUS_BASE_CONFIG_FILE"]
  41 prometheus_url = os.environ["PROMETHEUS_URL"]
  42
  43
  44 def get_jobs(client):
  45     return json.loads(dumps(client[target_database].prometheus_jobs.find({})))
  46
  47
  48 def save_successful_jobs(client, jobs):
  49     for job in jobs:
  50         client[target_database].prometheus_jobs.update_one(
  51             {"_id": ObjectId(job["_id"]["$oid"])},
  52             {"$set": {"is_active": True}}
  53         )
  54
  55
  56 def clean_up_job(prometheus_job):
  57     cleaned_prometheus_job = copy.deepcopy(prometheus_job)
  58     # take out _id and internal keys
  59     cleaned_prometheus_job.pop("_id", None)
  60     cleaned_prometheus_job.pop("is_active", None)
  61     cleaned_prometheus_job.pop("vnfr_id", None)
  62     cleaned_prometheus_job.pop("nsr_id", None)
  63     return cleaned_prometheus_job
  64
  65
  66 def generate_prometheus_config(prometheus_jobs, config_file_path):
  67     with open(config_file_path, encoding="utf-8", mode="r") as config_file:
  68         config_file_yaml = yaml.safe_load(config_file)
  69     if config_file_yaml is None:
  70         config_file_yaml = {}
  71     if "scrape_configs" not in config_file_yaml:
  72         config_file_yaml["scrape_configs"] = []
  73
  74     for prometheus_job in prometheus_jobs:
  75         cleaned_up_job = clean_up_job(prometheus_job)
  76         config_file_yaml["scrape_configs"].append(cleaned_up_job)
  77
  78     return config_file_yaml
  79
  80
  81 async def reload_prometheus_config(prom_url):
  82     async with aiohttp.ClientSession() as session:
  83         async with session.post(prom_url + "/-/reload") as resp:
  84             if resp.status > 204:
  85                 print(f"Error while updating prometheus config: {resp.text()}")
  86                 return False
  87         await asyncio.sleep(5)
  88         return True
  89
  90
  91 def check_configuration_equal(a_config, b_config):
  92     if a_config is None and b_config is None:
  93         return True
  94     if a_config is None or b_config is None:
  95         return False
  96     if "scrape_configs" not in a_config and "scrape_configs" not in b_config:
  97         return True
  98     if "scrape_configs" not in a_config or "scrape_configs" not in b_config:
  99         return False
 100     a_jobs = [j["job_name"] for j in a_config["scrape_configs"]]
 101     b_jobs = [j["job_name"] for j in b_config["scrape_configs"]]
 102
 103     return a_jobs == b_jobs
 104
 105
 106 async def validate_configuration(prom_url, new_config):
 107     async with aiohttp.ClientSession() as session:
 108         # Gets the configuration from prometheus
 109         # and compares with the inserted one
 110         # If prometheus does not admit this configuration,
 111         # the old one will remain
 112         async with session.get(prom_url + "/api/v1/status/config") as resp:
 113             if resp.status > 204:
 114                 print(f"Error while updating prometheus config: {resp.text()}")
 115                 return False
 116             current_config = await resp.json()
 117             return check_configuration_equal(
 118                 yaml.safe_load(current_config["data"]["yaml"]), new_config
 119             )
 120
 121
 122 async def main_task(client):
 123     stored_jobs = get_jobs(client)
 124     print(f"Jobs detected : {len(stored_jobs):d}")
 125     generated_prometheus_config = generate_prometheus_config(
 126         stored_jobs, prometheus_base_config_file
 127     )
 128     print(f"Writing new config file to {prometheus_config_file}")
 129     config_file = open(prometheus_config_file, "w")
 130     config_file.truncate(0)
 131     config_file.write(yaml.safe_dump(generated_prometheus_config))
 132     config_file.close()
 133     print("New config written, updating prometheus")
 134     update_resp = await reload_prometheus_config(prometheus_url)
 135     is_valid = await validate_configuration(
 136         prometheus_url, generated_prometheus_config
 137     )
 138     if update_resp and is_valid:
 139         print("Prometheus config update successful")
 140         save_successful_jobs(client, stored_jobs)
 141     else:
 142         print(
 143             "Error while updating prometheus config: "
 144             "current config doesn't match with updated values"
 145         )
 146
 147
 148 async def main():
 149     client = pymongo.MongoClient(mongodb_url)
 150     print("Connected to MongoDB!")
 151
 152     try:
 153         print("Refreshing prometheus config file for first time")
 154         await main_task(client)
 155     except Exception as error:
 156         print("Error in first configuration attempt!")
 157         print(error)
 158
 159     while True:
 160         try:
 161             # Needs mongodb in replica mode as this feature relies in OpLog
 162             change_stream = client[target_database].prometheus_jobs.watch(
 163                 [
 164                     {
 165                         "$match": {
 166                             # If you want to modify a particular job,
 167                             # delete and insert it again
 168                             "operationType": {"$in": ["insert", "delete"]}
 169                         }
 170                     }
 171                 ]
 172             )
 173
 174             # Single thread, no race conditions and ops are queued up in order
 175             print("Listening to changes in prometheus jobs collection")
 176             for change in change_stream:
 177                 print("Change detected, updating prometheus config")
 178                 await main_task(client)
 179                 print()
 180         except Exception as error:
 181             print(error)
 182         print(
 183             "Detected failure while listening to prometheus jobs collection, "
 184             "retrying..."
 185         )
 186         time.sleep(5)
 187
 188
 189 asyncio.run(main())