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 from bson.json_util import dumps
  33 from bson import ObjectId
  34
  35 #Env variables
  36 mongodb_url = os.environ['MONGODB_URL']
  37 target_database = os.environ['TARGET_DATABASE']
  38 prometheus_config_file = os.environ['PROMETHEUS_CONFIG_FILE']
  39 prometheus_url = os.environ['PROMETHEUS_URL']
  40
  41 def get_jobs(client):
  42   return json.loads(dumps(client[target_database].prometheus_jobs.find({})))
  43
  44 def save_successful_jobs(client, jobs):
  45   for job in jobs:
  46     client[target_database].prometheus_jobs.update_one({
  47       "_id": ObjectId(job["_id"]["$oid"])
  48     }, {
  49       "$set": {
  50         "is_active": True
  51       }
  52     })
  53
  54 def clean_up_job(prometheus_job):
  55   cleaned_prometheus_job = copy.deepcopy(prometheus_job)
  56   #take out _id and internal keys
  57   cleaned_prometheus_job.pop('_id', None)
  58   cleaned_prometheus_job.pop('is_active', None)
  59   cleaned_prometheus_job.pop('vnfr_id', None)
  60   cleaned_prometheus_job.pop('nsr_id', None)
  61   return cleaned_prometheus_job
  62
  63 def generate_prometheus_config(prometheus_jobs, config_file_path):
  64   config_file = open(config_file_path, encoding='utf-8', mode='r')
  65   config_file_contents = config_file.read()
  66   config_file.close()
  67
  68   config_file_yaml = yaml.load(config_file_contents, yaml.FullLoader)
  69   if config_file_yaml is None:
  70     config_file_yaml = {}
  71
  72   if len(prometheus_jobs) == 0:
  73     config_file_yaml['scrape_configs'] = []
  74     return config_file_yaml
  75
  76   config_file_yaml['scrape_configs'] = []
  77
  78   for prometheus_job in prometheus_jobs:
  79     cleaned_up_job = clean_up_job(prometheus_job)
  80     config_file_yaml['scrape_configs'].append(cleaned_up_job)
  81
  82   return config_file_yaml
  83
  84 async def reload_prometheus_config(the_prometheus_url):
  85   async with aiohttp.ClientSession() as session:
  86     async with session.post(the_prometheus_url + "/-/reload") as resp:
  87       if resp.status > 204:
  88         print(f"Error while updating prometheus config : {resp.text()}")
  89         return False
  90     await asyncio.sleep(5)
  91     return True
  92
  93 def check_configuration_equal(a_config, b_config):
  94   if a_config is None and b_config is None:
  95     return True
  96   if a_config is None or b_config is None:
  97     return False
  98   if not "scrape_configs" in a_config and not "scrape_configs" in b_config:
  99     return True
 100   if not "scrape_configs" in a_config or not "scrape_configs" in b_config:
 101     return False
 102   a_jobs = [j["job_name"] for j in a_config["scrape_configs"]]
 103   b_jobs = [j["job_name"] for j in b_config["scrape_configs"]]
 104
 105   return a_jobs == b_jobs
 106
 107 async def validate_configuration(the_prometheus_url, new_config):
 108   async with aiohttp.ClientSession() as session:
 109     # If prometheus does not admit this configuration, remains with the old one
 110     # Then, to check if the configuration has been accepted, get the configuration from prometheus
 111     # and compares with the inserted one
 112     async with session.get(the_prometheus_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(yaml.load(current_config["data"]["yaml"], yaml.FullLoader), new_config)
 118
 119 async def main_task(client):
 120   stored_jobs = get_jobs(client)
 121   print(f"Jobs detected : {len(stored_jobs):d}")
 122   generated_prometheus_config = generate_prometheus_config(stored_jobs, prometheus_config_file)
 123   print(f"Writing new config file to {prometheus_config_file}")
 124   config_file = open(prometheus_config_file, "w")
 125   config_file.truncate(0)
 126   config_file.write(yaml.dump(generated_prometheus_config))
 127   config_file.close()
 128   print("New config written, updating prometheus")
 129   update_resp = await reload_prometheus_config(prometheus_url)
 130   is_valid = await validate_configuration(prometheus_url, generated_prometheus_config)
 131   if update_resp and is_valid:
 132     print("Prometheus config update successful")
 133     save_successful_jobs(client, stored_jobs)
 134   else:
 135     print("Error while updating prometheus config: current config doesn't match with updated values")
 136
 137 async def main():
 138   client = pymongo.MongoClient(mongodb_url)
 139   print('Connected to MongoDB!')
 140
 141   print('Refreshing prometheus config file for first time')
 142   await main_task(client)
 143
 144   #Needs mongodb in replica mode as this feature relies in OpLog
 145   change_stream = client[target_database].prometheus_jobs.watch([{
 146     '$match': {
 147       #If you want to modify a particular job, delete and insert it again
 148       'operationType': { '$in': ['insert', 'delete'] }
 149     }
 150   }])
 151
 152   #Single thread, no race conditions and ops are queued up in order
 153   for change in change_stream:
 154     print("Change detected, updating prometheus config")
 155     await main_task(client)
 156     print()
 157
 158 asyncio.run(main())