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