#!/usr/bin/env python3 # psql.py - PVC Monitoring example plugin for Postgres/Patroni # Part of the Parallel Virtual Cluster (PVC) system # # Copyright (C) 2018-2022 Joshua M. Boniface # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, version 3. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see . # ############################################################################### # This script provides an example of a PVC monitoring plugin script. It will create # a simple plugin to check the Patroni PostgreSQL instance on the node for operation. # This script can thus be used as an example or reference implementation of a # PVC monitoring pluginscript and expanded upon as required. # A monitoring plugin script must implement the class "MonitoringPluginScript" which # extends "MonitoringPlugin", providing the 3 functions indicated. Detailed explanation # of the role of each function is provided in context of the example; see the other # examples for more potential uses. # WARNING: # # This script will run in the context of the node daemon keepalives as root. # DO NOT install untrusted, unvetted plugins under any circumstances. # This import is always required here, as MonitoringPlugin is used by the # MonitoringPluginScript class from pvcnoded.objects.MonitoringInstance import MonitoringPlugin # A monitoring plugin script must always expose its nice name, which must be identical to # the file name PLUGIN_NAME = "psql" # The MonitoringPluginScript class must be named as such, and extend MonitoringPlugin. class MonitoringPluginScript(MonitoringPlugin): def setup(self): """ setup(): Perform special setup steps during node daemon startup This step is optional and should be used sparingly. """ pass def run(self): """ run(): Perform the check actions and return a PluginResult object """ # Run any imports first from psycopg2 import connect conn_metadata = None cur_metadata = None conn_dns = None cur_dns = None # Set the health delta to 0 (no change) health_delta = 0 # Craft a message that can be used by the clients message = "Successfully connected to PostgreSQL databases on localhost" # Check the Metadata database (primary) try: conn_metadata = connect( host='127.0.0.1', port=self.config["metadata_postgresql_port"], dbname=self.config["metadata_postgresql_dbname"], user=self.config["metadata_postgresql_user"], password=self.config["metadata_postgresql_password"], ) cur_metadata = conn_metadata.cursor() cur_metadata.execute("""SELECT * FROM alembic_version""") data = cur_metadata.fetchone() except Exception as e: health_delta = 50 err = str(e).split('\n')[0] message = f"Failed to connect to PostgreSQL database {self.config['metadata_postgresql_dbname']}: {err}" finally: if cur_metadata is not None: cur_metadata.close() if conn_metadata is not None: conn_metadata.close() if health_delta == 0: # Check the PowerDNS database (secondary) try: conn_pdns = connect( host='127.0.0.1', port=self.config["pdns_postgresql_port"], dbname=self.config["pdns_postgresql_dbname"], user=self.config["pdns_postgresql_user"], password=self.config["pdns_postgresql_password"], ) cur_pdns = conn_pdns.cursor() cur_pdns.execute("""SELECT * FROM supermasters""") data = cur_pdns.fetchone() except Exception as e: health_delta = 50 err = str(e).split('\n')[0] message = f"Failed to connect to PostgreSQL database {self.config['pdns_postgresql_dbname']}: {err}" finally: if cur_pdns is not None: cur_pdns.close() if conn_pdns is not None: conn_pdns.close() # Set the health delta in our local PluginResult object self.plugin_result.set_health_delta(health_delta) # Set the message in our local PluginResult object self.plugin_result.set_message(message) # Return our local PluginResult object return self.plugin_result def cleanup(self): """ cleanup(): Perform special cleanup steps during node daemon termination This step is optional and should be used sparingly. """ pass