diff options
Diffstat (limited to 'src/system')
| -rwxr-xr-x | src/system/vyos-event-handler.py | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/src/system/vyos-event-handler.py b/src/system/vyos-event-handler.py new file mode 100755 index 000000000..1c85380bc --- /dev/null +++ b/src/system/vyos-event-handler.py @@ -0,0 +1,162 @@ +#!/usr/bin/env python3 +# +# Copyright (C) 2022 VyOS maintainers and contributors +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License version 2 or later as +# published by the Free Software Foundation. +# +# 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 <http://www.gnu.org/licenses/>. + +import argparse +import json +import re +import select +from copy import deepcopy +from os import getpid, environ +from pathlib import Path +from signal import signal, SIGTERM, SIGINT +from sys import exit +from systemd import journal + +from vyos.util import run, dict_search + +# Identify this script +my_pid = getpid() +my_name = Path(__file__).stem + + +# handle termination signal +def handle_signal(signal_type, frame): + if signal_type == SIGTERM: + journal.send('Received SIGTERM signal, stopping normally', + SYSLOG_IDENTIFIER=my_name) + if signal_type == SIGINT: + journal.send('Received SIGINT signal, stopping normally', + SYSLOG_IDENTIFIER=my_name) + exit(0) + + +# Class for analyzing and process messages +class Analyzer: + # Initialize settings + def __init__(self, config: dict) -> None: + self.config = {} + # Prepare compiled regex objects + for event_id, event_config in config.items(): + script = dict_search('script.path', event_config) + # Check for arguments + if dict_search('script.arguments', event_config): + script_arguments = dict_search('script.arguments', event_config) + script = f'{script} {script_arguments}' + # Prepare environment + environment = deepcopy(environ) + # Check for additional environment options + if dict_search('script.environment', event_config): + for env_variable, env_value in dict_search( + 'script.environment', event_config).items(): + environment[env_variable] = env_value.get('value') + # Create final config dictionary + pattern_raw = event_config['filter']['pattern'] + pattern_compiled = re.compile( + rf'{event_config["filter"]["pattern"]}') + pattern_config = { + pattern_compiled: { + 'pattern_raw': + pattern_raw, + 'syslog_id': + dict_search('filter.syslog-identifier', event_config), + 'pattern_script': { + 'path': script, + 'environment': environment + } + } + } + self.config.update(pattern_config) + + # Execute script safely + def script_run(self, pattern: str, script_path: str, + script_env: dict) -> None: + try: + run(script_path, env=script_env) + journal.send( + f'Pattern found: "{pattern}", script executed: "{script_path}"', + SYSLOG_IDENTIFIER=my_name) + except Exception as err: + journal.send( + f'Pattern found: "{pattern}", failed to execute script "{script_path}": {err}', + SYSLOG_IDENTIFIER=my_name) + + # Analyze a message + def process_message(self, message: dict) -> None: + for pattern_compiled, pattern_config in self.config.items(): + # Check if syslog id is presented in config and matches + syslog_id = pattern_config.get('syslog_id') + if syslog_id and message['SYSLOG_IDENTIFIER'] != syslog_id: + continue + if pattern_compiled.fullmatch(message['MESSAGE']): + # Add message to environment variables + pattern_config['pattern_script']['environment'][ + 'message'] = message['MESSAGE'] + # Run script + self.script_run( + pattern=pattern_config['pattern_raw'], + script_path=pattern_config['pattern_script']['path'], + script_env=pattern_config['pattern_script']['environment']) + + +if __name__ == '__main__': + # Parse command arguments and get config + parser = argparse.ArgumentParser() + parser.add_argument('-c', + '--config', + action='store', + help='Path to even-handler configuration', + required=True, + type=Path) + + args = parser.parse_args() + try: + config_path = Path(args.config) + config = json.loads(config_path.read_text()) + # Create an object for analazyng messages + analyzer = Analyzer(config) + except Exception as err: + print( + f'Configuration file "{config_path}" does not exist or malformed: {err}' + ) + exit(1) + + # Prepare for proper exitting + signal(SIGTERM, handle_signal) + signal(SIGINT, handle_signal) + + # Set up journal connection + data = journal.Reader() + data.seek_tail() + data.get_previous() + p = select.poll() + p.register(data, data.get_events()) + + journal.send(f'Started with configuration: {config}', + SYSLOG_IDENTIFIER=my_name) + + while p.poll(): + if data.process() != journal.APPEND: + continue + for entry in data: + message = entry['MESSAGE'] + pid = entry['_PID'] + # Skip empty messages and messages from this process + if message and pid != my_pid: + try: + analyzer.process_message(entry) + except Exception as err: + journal.send(f'Unable to process message: {err}', + SYSLOG_IDENTIFIER=my_name) |