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"]["$oid"])}, {"$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     with open(config_file_path, encoding="utf-8", mode="r") as config_file:
  67         config_file_yaml = yaml.safe_load(config_file)
  68     if config_file_yaml is None:
  69         config_file_yaml = {}
  70     if "scrape_configs" not in config_file_yaml:
  71         config_file_yaml["scrape_configs"] = []
  72
  73     for prometheus_job in prometheus_jobs:
  74         cleaned_up_job = clean_up_job(prometheus_job)
  75         config_file_yaml["scrape_configs"].append(cleaned_up_job)
  76
  77     return config_file_yaml
  78
  79
  80 async def reload_prometheus_config(prom_url):
  81     async with aiohttp.ClientSession() as session:
  82         async with session.post(prom_url + "/-/reload") as resp:
  83             if resp.status > 204:
  84                 print(f"Error while updating prometheus config: {resp.text()}")
  85                 return False
  86         await asyncio.sleep(5)
  87         return True
  88
  89
  90 def check_configuration_equal(a_config, b_config):
  91     if a_config is None and b_config is None:
  92         return True
  93     if a_config is None or b_config is None:
  94         return False
  95     if "scrape_configs" not in a_config and "scrape_configs" not in b_config:
  96         return True
  97     if "scrape_configs" not in a_config or "scrape_configs" not in b_config:
  98         return False
  99     a_jobs = [j["job_name"] for j in a_config["scrape_configs"]]
 100     b_jobs = [j["job_name"] for j in b_config["scrape_configs"]]
 101
 102     return a_jobs == b_jobs
 103
 104
 105 async def validate_configuration(prom_url, new_config):
 106     async with aiohttp.ClientSession() as session:
 107         # Gets the configuration from prometheus
 108         # and compares with the inserted one
 109         # If prometheus does not admit this configuration,
 110         # the old one will remain
 111         async with session.get(prom_url + "/api/v1/status/config") as resp:
 112             if resp.status > 204:
 113                 print(f"Error while updating prometheus config: {resp.text()}")
 114                 return False
 115             current_config = await resp.json()
 116             return check_configuration_equal(
 117                 yaml.safe_load(current_config["data"]["yaml"]), new_config
 118             )
 119
 120
 121 async def main_task(client):
 122     stored_jobs = get_jobs(client)
 123     print(f"Jobs detected : {len(stored_jobs):d}")
 124     generated_prometheus_config = generate_prometheus_config(
 125         stored_jobs, prometheus_base_config_file
 126     )
 127     print(f"Writing new config file to {prometheus_config_file}")
 128     config_file = open(prometheus_config_file, "w")
 129     config_file.truncate(0)
 130     config_file.write(yaml.safe_dump(generated_prometheus_config))
 131     config_file.close()
 132     print("New config written, updating prometheus")
 133     update_resp = await reload_prometheus_config(prometheus_url)
 134     is_valid = await validate_configuration(prometheus_url, generated_prometheus_config)
 135     if update_resp and is_valid:
 136         print("Prometheus config update successful")
 137         save_successful_jobs(client, stored_jobs)
 138     else:
 139         print(
 140             "Error while updating prometheus config: "
 141             "current config doesn't match with updated values"
 142         )
 143
 144
 145 async def main():
 146     client = pymongo.MongoClient(mongodb_url)
 147     print("Created MongoClient to connect to MongoDB!")
 148
 149     # Initial loop. First refresh of prometheus config file
 150     first_refresh_completed = False
 151     tries = 1
 152     while tries <= 3:
 153         try:
 154             print("Refreshing prometheus config file for first time")
 155             await main_task(client)
 156             first_refresh_completed = True
 157         except Exception as error:
 158             print(f"Error in configuration attempt! Number of tries: {tries}/3")
 159             print(error)
 160         time.sleep(5)
 161         tries += 1
 162     if not first_refresh_completed:
 163         print("Not possible to refresh prometheus config file for first time")
 164         return
 165
 166     # Main loop
 167     while True:
 168         try:
 169             # Needs mongodb in replica mode as this feature relies in OpLog
 170             change_stream = client[target_database].prometheus_jobs.watch(
 171                 [
 172                     {
 173                         "$match": {
 174                             # If you want to modify a particular job,
 175                             # delete and insert it again
 176                             "operationType": {"$in": ["insert", "delete"]}
 177                         }
 178                     }
 179                 ]
 180             )
 181
 182             # Single thread, no race conditions and ops are queued up in order
 183             print("Listening to changes in prometheus jobs collection")
 184             for change in change_stream:
 185                 print("Change detected, updating prometheus config")
 186                 print(f"{change}")
 187                 await main_task(client)
 188                 print()
 189         except Exception as error:
 190             print(error)
 191         print(
 192             "Detected failure while listening to prometheus jobs collection, "
 193             "retrying..."
 194         )
 195         time.sleep(5)
 196
 197
 198 asyncio.run(main())