osm_lcm/prometheus.py

   1 # -*- coding: utf-8 -*-
   2
   3 ##
   4 # Copyright 2020 Telefonica S.A.
   5 #
   6 # Licensed under the Apache License, Version 2.0 (the "License"); you may
   7 # not use this file except in compliance with the License. You may obtain
   8 # a copy of the License at
   9 #
  10 #         http://www.apache.org/licenses/LICENSE-2.0
  11 #
  12 # Unless required by applicable law or agreed to in writing, software
  13 # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  14 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  15 # License for the specific language governing permissions and limitations
  16 # under the License.
  17 ##
  18
  19 import asyncio
  20 from time import time
  21 import logging
  22 import aiohttp
  23 import yaml
  24 import os
  25 from osm_lcm.lcm_utils import LcmException
  26 from osm_common.dbbase import DbException
  27 from osm_lcm.data_utils.database.database import Database
  28 from jinja2 import Template, TemplateError, TemplateNotFound, TemplateSyntaxError
  29
  30 __author__ = "Alfonso Tierno <alfonso.tiernosepulveda@telefonica.com>"
  31
  32 initial_prometheus_data = {
  33     "_id": "prometheus",
  34     "_admin": {
  35         "locked_at": 0,
  36         "locked_by": None,
  37         "modified": 1593445184,  # 2020-06-29
  38         "created": 1593445184,
  39         "version": "1.0"    # to allow future version updates
  40     },
  41     'scrape_configs': {   # Dictionary at database. Converted to list before sending to prometheus
  42         'mon_exporter': {'static_configs': [{'targets': ['mon:8000']}], 'job_name': 'mon_exporter'},
  43     },
  44     'global': {'evaluation_interval': '15s', 'scrape_interval': '15s'},
  45     'rule_files': None,
  46     'alerting': {'alertmanagers': [{'static_configs': [{'targets': None}]}]}
  47 }
  48
  49
  50 class Prometheus:
  51     """
  52     Implements a class to update Prometheus
  53     """
  54
  55     PROMETHEUS_LOCKED_TIME = 120
  56
  57     def __init__(self, config, worker_id, loop, logger=None):
  58         self.worker_id = worker_id
  59         self.db = Database().instance.db
  60         self.loop = loop
  61         self.logger = logger or logging.getLogger("lcm.prometheus")
  62         self.server = config["uri"]
  63         self.path = config["path"]
  64         if not self.path.endswith("/"):
  65             self.path += "/"
  66         self.cfg_file = self.path + "prometheus.yml"
  67         self.cfg_file_backup = self.path + "prometheus.yml-backup"
  68
  69     @staticmethod
  70     def parse_job(job_data: str, variables: dict) -> dict:
  71         try:
  72             template = Template(job_data)
  73             job_parsed = template.render(variables or {})
  74             return yaml.safe_load(job_parsed)
  75         except (TemplateError, TemplateNotFound, TemplateSyntaxError) as e:
  76             # TODO yaml exceptions
  77             raise LcmException("Error parsing Jinja2 to prometheus job. job_data={}, variables={}. Error={}".format(
  78                 job_data, variables, e))
  79
  80     async def start(self):
  81         for retry in range(4):
  82             try:
  83                 # self.logger("Starting prometheus ")
  84                 # read from database
  85                 prometheus_data = self.db.get_one("admin", {"_id": "prometheus"}, fail_on_empty=False)
  86                 if not prometheus_data:
  87                     self.logger.info("Init db.admin.prometheus content")
  88                     self.db.create("admin", initial_prometheus_data)
  89                 # send database config file to prometheus. Ignore loading errors, as prometheus may be starting
  90                 # but at least an initial configuration file is set
  91                 await self.update()
  92                 return
  93             except DbException as e:
  94                 if retry == 3:
  95                     raise LcmException("Max retries trying to init prometheus configuration: {}".format(e))
  96                 await asyncio.sleep(5, loop=self.loop)
  97
  98     async def update(self, add_jobs: dict = None, remove_jobs: list = None) -> bool:
  99         """
 100
 101         :param add_jobs: dictionary with {job_id_1: job_content, job_id_2: job_content}
 102         :param remove_jobs: list with jobs to remove [job_id_1, job_id_2]
 103         :return: result. If false prometheus denies this configuration. Exception on error
 104         """
 105         for retry in range(20):
 106             result = True
 107             if retry:  # first time do not wait
 108                 await asyncio.sleep(4 + retry, loop=self.loop)
 109
 110             # lock database
 111             now = time()
 112             if not self.db.set_one(
 113                     "admin",
 114                     q_filter={"_id": "prometheus", "_admin.locked_at.lt": now - self.PROMETHEUS_LOCKED_TIME},
 115                     update_dict={"_admin.locked_at": now, "_admin.locked_by": self.worker_id},
 116                     fail_on_empty=False):
 117                 continue
 118             # read database
 119             prometheus_data = self.db.get_one("admin", {"_id": "prometheus"})
 120             update_dict = {"_admin.locked_at": 0,
 121                            "_admin.locked_by": None}
 122
 123             # Make changes from prometheus_incremental
 124             push_dict = pull_dict = None
 125             if add_jobs or remove_jobs:
 126                 log_text_list = []
 127                 if add_jobs:
 128                     log_text_list.append("adding jobs: {}".format(list(add_jobs.keys())))
 129                     prometheus_data["scrape_configs"].update(add_jobs)
 130                     push_dict = {"scrape_configs." + job_id: job_data for job_id, job_data in add_jobs.items()}
 131                 elif remove_jobs:
 132                     log_text_list.append("removing jobs: {}".format(list(remove_jobs)))
 133                     for job_id in remove_jobs:
 134                         prometheus_data["scrape_configs"].pop(job_id, None)
 135                     pull_dict = {"scrape_configs." + job_id: None for job_id in remove_jobs}
 136                 self.logger.debug("Updating. " + ". ".join(log_text_list))
 137
 138             if not await self.send_data(prometheus_data):
 139                 self.logger.error("Cannot update add_jobs: {}. remove_jobs: {}".format(add_jobs, remove_jobs))
 140                 push_dict = pull_dict = None
 141                 result = False
 142
 143             # unblock database
 144             if push_dict:
 145                 update_dict.update(push_dict)
 146             if push_dict or pull_dict:
 147                 update_dict["_admin.modified_at"] = now
 148             if not self.db.set_one(
 149                     "admin", {"_id": "prometheus", "_admin.locked_at": now, "_admin.locked_by": self.worker_id},
 150                     update_dict=update_dict, unset=pull_dict, fail_on_empty=False):
 151                 continue
 152             return result
 153         raise LcmException("Cannot update prometheus database. Reached max retries")
 154
 155     async def send_data(self, new_config):
 156         restore_backup = False
 157         del new_config["_id"]
 158         del new_config["_admin"]
 159         new_scrape_configs = []
 160
 161         # generate a list with the values of scrape_configs
 162         for scrape_config in new_config["scrape_configs"].values():
 163             scrape_config = scrape_config.copy()
 164             # remove nsr_id metadata from scrape_configs
 165             scrape_config.pop("nsr_id", None)
 166             new_scrape_configs.append(scrape_config)
 167         new_config["scrape_configs"] = new_scrape_configs
 168
 169         try:
 170             if os.path.exists(self.cfg_file):
 171                 os.rename(self.cfg_file, self.cfg_file_backup)
 172                 restore_backup = True
 173             with open(self.cfg_file, "w+") as f:
 174                 yaml.safe_dump(new_config, f, indent=4, default_flow_style=False)
 175             # self.logger.debug("new configuration: {}".format(yaml.safe_dump(new_config, indent=4,
 176             #                                                                 default_flow_style=False)))
 177             async with aiohttp.ClientSession() as session:
 178                 async with session.post(self.server + "-/reload") as resp:
 179                     if resp.status > 204:
 180                         raise LcmException(await resp.text())
 181                 await asyncio.sleep(5, loop=self.loop)
 182                 # If prometheus does not admit this configuration, remains with the old one
 183                 # Then, to check if the configuration has been accepted, get the configuration from prometheus
 184                 # and compares with the inserted one
 185                 async with session.get(self.server + "api/v1/status/config") as resp:
 186                     if resp.status > 204:
 187                         raise LcmException(await resp.text())
 188                     current_config = await resp.json()
 189                     if not self._check_configuration_equal(current_config, new_config):
 190                         return False
 191                     else:
 192                         restore_backup = False
 193             return True
 194         except Exception as e:
 195             self.logger.error("Error updating configuration url={}: {}".format(self.server, e))
 196             return False
 197         finally:
 198             if restore_backup:
 199                 try:
 200                     os.rename(self.cfg_file_backup, self.cfg_file)
 201                 except Exception as e:
 202                     self.logger.critical("Exception while rolling back: {}".format(e))
 203
 204     def _check_configuration_equal(self, current_config, expected_config):
 205         try:
 206             # self.logger.debug("Comparing current_config='{}' with expected_config='{}'".format(current_config,
 207             #                                                                                    expected_config))
 208             current_config_yaml = yaml.safe_load(current_config['data']['yaml'])
 209             current_jobs = [j["job_name"] for j in current_config_yaml["scrape_configs"]]
 210             expected_jobs = [j["job_name"] for j in expected_config["scrape_configs"]]
 211             if current_jobs == expected_jobs:
 212                 return True
 213             else:
 214                 self.logger.error("Not all jobs have been loaded. Target jobs: {} Loaded jobs: {}".format(
 215                     expected_jobs, current_jobs))
 216                 return False
 217         except Exception as e:
 218             self.logger.error("Invalid obtained status from server. Error: '{}'. Obtained data: '{}'".format(
 219                 e, current_config))
 220             # if format is not understood, cannot be compared, assume it is ok
 221             return True