#!/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.
        """

        pass

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

        # Run any imports first
        from re import match
        from json import dumps
        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(dumps(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