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_url = os.environ["PROMETHEUS_URL"]
  41
  42
  43 def get_jobs(client):
  44     return json.loads(dumps(client[target_database].prometheus_jobs.find({})))
  45
  46
  47 def save_successful_jobs(client, jobs):
  48     for job in jobs:
  49         client[target_database].prometheus_jobs.update_one(
  50             {"_id": ObjectId(job["_id"]["$oid"])},
  51             {"$set": {"is_active": True}}
  52         )
  53
  54
  55 def clean_up_job(prometheus_job):
  56     cleaned_prometheus_job = copy.deepcopy(prometheus_job)
  57     # take out _id and internal keys
  58     cleaned_prometheus_job.pop("_id", None)
  59     cleaned_prometheus_job.pop("is_active", None)
  60     cleaned_prometheus_job.pop("vnfr_id", None)
  61     cleaned_prometheus_job.pop("nsr_id", None)
  62     return cleaned_prometheus_job
  63
  64
  65 def generate_prometheus_config(prometheus_jobs, config_file_path):
  66     config_file = open(config_file_path, encoding="utf-8", mode="r")
  67     config_file_contents = config_file.read()
  68     config_file.close()
  69
  70     config_file_yaml = yaml.load(config_file_contents, yaml.FullLoader)
  71     if config_file_yaml is None:
  72         config_file_yaml = {}
  73
  74     if len(prometheus_jobs) == 0:
  75         config_file_yaml["scrape_configs"] = []
  76         return config_file_yaml
  77
  78     config_file_yaml["scrape_configs"] = []
  79
  80     for prometheus_job in prometheus_jobs:
  81         cleaned_up_job = clean_up_job(prometheus_job)
  82         config_file_yaml["scrape_configs"].append(cleaned_up_job)
  83
  84     return config_file_yaml
  85
  86
  87 async def reload_prometheus_config(prom_url):
  88     async with aiohttp.ClientSession() as session:
  89         async with session.post(prom_url + "/-/reload") as resp:
  90             if resp.status > 204:
  91                 print(f"Error while updating prometheus config: {resp.text()}")
  92                 return False
  93         await asyncio.sleep(5)
  94         return True
  95
  96
  97 def check_configuration_equal(a_config, b_config):
  98     if a_config is None and b_config is None:
  99         return True
 100     if a_config is None or b_config is None:
 101         return False
 102     if "scrape_configs" not in a_config and "scrape_configs" not in b_config:
 103         return True
 104     if "scrape_configs" not in a_config or "scrape_configs" not in b_config:
 105         return False
 106     a_jobs = [j["job_name"] for j in a_config["scrape_configs"]]
 107     b_jobs = [j["job_name"] for j in b_config["scrape_configs"]]
 108
 109     return a_jobs == b_jobs
 110
 111
 112 async def validate_configuration(prom_url, new_config):
 113     async with aiohttp.ClientSession() as session:
 114         # Gets the configuration from prometheus
 115         # and compares with the inserted one
 116         # If prometheus does not admit this configuration,
 117         # the old one will remain
 118         async with session.get(prom_url + "/api/v1/status/config") as resp:
 119             if resp.status > 204:
 120                 print(f"Error while updating prometheus config: {resp.text()}")
 121                 return False
 122             current_config = await resp.json()
 123             return check_configuration_equal(
 124                 yaml.safe_load(current_config["data"]["yaml"]), new_config
 125             )
 126
 127
 128 async def main_task(client):
 129     stored_jobs = get_jobs(client)
 130     print(f"Jobs detected : {len(stored_jobs):d}")
 131     generated_prometheus_config = generate_prometheus_config(
 132         stored_jobs, prometheus_config_file
 133     )
 134     print(f"Writing new config file to {prometheus_config_file}")
 135     config_file = open(prometheus_config_file, "w")
 136     config_file.truncate(0)
 137     config_file.write(yaml.dump(generated_prometheus_config))
 138     config_file.close()
 139     print("New config written, updating prometheus")
 140     update_resp = await reload_prometheus_config(prometheus_url)
 141     is_valid = await validate_configuration(
 142         prometheus_url, generated_prometheus_config
 143     )
 144     if update_resp and is_valid:
 145         print("Prometheus config update successful")
 146         save_successful_jobs(client, stored_jobs)
 147     else:
 148         print(
 149             "Error while updating prometheus config: "
 150             "current config doesn't match with updated values"
 151         )
 152
 153
 154 async def main():
 155     client = pymongo.MongoClient(mongodb_url)
 156     print("Connected to MongoDB!")
 157
 158     try:
 159         print("Refreshing prometheus config file for first time")
 160         await main_task(client)
 161     except Exception as error:
 162         print("Error in first configuration attempt!")
 163         print(error)
 164
 165     while True:
 166         try:
 167             # Needs mongodb in replica mode as this feature relies in OpLog
 168             change_stream = client[target_database].prometheus_jobs.watch(
 169                 [
 170                     {
 171                         "$match": {
 172                             # If you want to modify a particular job,
 173                             # delete and insert it again
 174                             "operationType": {"$in": ["insert", "delete"]}
 175                         }
 176                     }
 177                 ]
 178             )
 179
 180             # Single thread, no race conditions and ops are queued up in order
 181             print("Listening to changes in prometheus jobs collection")
 182             for change in change_stream:
 183                 print("Change detected, updating prometheus config")
 184                 await main_task(client)
 185                 print()
 186         except Exception as error:
 187             print(error)
 188         print(
 189             "Detected failure while listening to prometheus jobs collection, "
 190             "retrying..."
 191         )
 192         time.sleep(5)
 193
 194
 195 asyncio.run(main())