From 06c0d2f2f9f4b9c97eb9868df166d787ca367ee7 Mon Sep 17 00:00:00 2001 From: zsdc Date: Tue, 7 Jun 2022 14:34:49 +0300 Subject: event-handler: T3083: Extended event-handler features * Added the ability to filter by a syslog identifier * Added the ability to pass arguments to a script * Added the ability to pass preconfigured environment variables to a script * A message that triggered a script is now passed in the `message` variable and can be used in a script * Replaced `call()` to `run()`, since stdout are not need to be printed --- src/system/vyos-event-handler.py | 110 ++++++++++++++++++++++++++------------- 1 file changed, 75 insertions(+), 35 deletions(-) (limited to 'src/system/vyos-event-handler.py') diff --git a/src/system/vyos-event-handler.py b/src/system/vyos-event-handler.py index f4b793dbe..691f674b2 100755 --- a/src/system/vyos-event-handler.py +++ b/src/system/vyos-event-handler.py @@ -18,12 +18,12 @@ import argparse import select import re import json -from os import getpid +from os import getpid, environ from pathlib import Path from signal import signal, SIGTERM, SIGINT from systemd import journal from sys import exit -from vyos.util import call +from vyos.util import run, dict_search # Identify this script my_pid = getpid() @@ -41,25 +41,72 @@ def handle_signal(signal_type, frame): exit(0) -# Execute script safely -def script_run(pattern: str, script_path: str) -> None: - try: - call(script_path) - 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) - - -# iterate trough regexp items -def analyze_message(message: str, regex_patterns: dict) -> None: - for pattern_compiled, pattern_config in regex_patterns.items(): - if pattern_compiled.match(message): - script_run(pattern_config['pattern_raw'], - pattern_config['pattern_script']) +# 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 = 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__': @@ -76,6 +123,8 @@ if __name__ == '__main__': 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}' @@ -93,19 +142,6 @@ if __name__ == '__main__': p = select.poll() p.register(data, data.get_events()) - # Prepare compiled regex objects - patterns = {} - for name, event_config in config.items(): - pattern_raw = f'{event_config["pattern"]}' - pattern_compiled = re.compile(rf'{event_config["pattern"]}') - pattern_config = { - pattern_compiled: { - 'pattern_raw': pattern_raw, - 'pattern_script': event_config['script'] - } - } - patterns.update(pattern_config) - journal.send(f'Started with configuration: {config}', SYSLOG_IDENTIFIER=my_name) @@ -117,4 +153,8 @@ if __name__ == '__main__': pid = entry['_PID'] # Skip empty messages and messages from this process if message and pid != my_pid: - analyze_message(message, patterns) + try: + analyzer.process_message(entry) + except Exception as err: + journal.send(f'Unable to process message: {err}', + SYSLOG_IDENTIFIER=my_name) -- cgit v1.2.3