#!/usr/bin/env python3

# dpkg.py - PVC Monitoring example plugin for dpkg status
# Part of the Parallel Virtual Cluster (PVC) system
#
#    Copyright (C) 2018-2022 Joshua M. Boniface <joshua@boniface.me>
#
#    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 <https://www.gnu.org/licenses/>.
#
###############################################################################

# This script provides an example of a PVC monitoring plugin script. It will create
# a simple plugin to check the system dpkg status is as expected, with no invalid
# packages or obsolete configuration files, and will return a 1 health delta for each
# flaw in invalid packages, upgradable packages, and obsolete config files.

# 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 = "dpkg"


# 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.

        If you wish for the plugin to not load in certain conditions, do any checks here
        and return a non-None failure message to indicate the error.
        """

        pass

    def run(self):
        """
        run(): Perform the check actions and return a PluginResult object
        """

        # Run any imports first
        from re import match
        import daemon_lib.common as pvc_common

        # Get Debian version
        with open('/etc/debian_version', 'r') as fh:
            debian_version = fh.read().strip()

        # Get a list of dpkg packages for analysis
        retcode, stdout, stderr = pvc_common.run_os_command("/usr/bin/dpkg --list")

        # Get a list of installed packages and states
        packages = list()
        for dpkg_line in stdout.split('\n'):
            if match('^[a-z][a-z] ', dpkg_line):
                line_split = dpkg_line.split()
                package_state = line_split[0]
                package_name = line_split[1]
                packages.append((package_name, package_state))

        count_ok = 0
        count_inconsistent = 0
        list_inconsistent = list()

        for package in packages:
            if package[1] == "ii":
                count_ok += 1
            else:
                count_inconsistent += 1
                list_inconsistent.append(package[0])

        # Get upgradable packages
        retcode, stdout, stderr = pvc_common.run_os_command("/usr/bin/apt list --upgradable")

        list_upgradable = list()
        for apt_line in stdout.split('\n'):
            if match('^[a-z][a-z] ', apt_line):
                line_split = apt_line.split('/')
                package_name = line_split[0]
                list_upgradable.append(package_name)

        count_upgradable = len(list_upgradable)

        # Get obsolete config files (dpkg-* or ucf-* under /etc)
        retcode, stdout, stderr = pvc_common.run_os_command("/usr/bin/find /etc -type f -a \( -name '*.dpkg-*' -o -name '*.ucf-*' \)")

        obsolete_conffiles = list()
        for conffile_line in stdout.split('\n'):
            if conffile_line:
                obsolete_conffiles.append(conffile_line)

        count_obsolete_conffiles = len(obsolete_conffiles)

        # Set health_delta based on the results
        health_delta = 0
        if count_inconsistent > 0:
            health_delta += 1
        if count_upgradable > 0:
            health_delta += 1
        if count_obsolete_conffiles > 0:
            health_delta += 1

        # Set the health delta in our local PluginResult object
        self.plugin_result.set_health_delta(health_delta)

        # Craft the message
        message = f"Debian {debian_version}; Obsolete conffiles: {count_obsolete_conffiles}; Packages valid: {count_ok}, inconsistent: {count_inconsistent}, upgradable: {count_upgradable}"

        # Set the message in our local PluginResult object
        self.plugin_result.set_message(message)

        # Set the detailed data in our local PluginResult object
        detailed_data = {
            "debian_version": debian_version,
            "obsolete_conffiles": obsolete_conffiles,
            "inconsistent_packages": list_inconsistent,
            "upgradable_packages": list_upgradable,
        }
        self.plugin_result.set_data(detailed_data)

        # 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