diff options
| -rw-r--r-- | interface-definitions/service-event-handler.xml.in | 70 | ||||
| -rwxr-xr-x | src/conf_mode/service_event_handler.py | 93 | ||||
| -rwxr-xr-x | src/system/vyos-event-handler.py | 162 | ||||
| -rw-r--r-- | src/systemd/vyos-event-handler.service | 11 |
4 files changed, 336 insertions, 0 deletions
diff --git a/interface-definitions/service-event-handler.xml.in b/interface-definitions/service-event-handler.xml.in new file mode 100644 index 000000000..aef6bc1bc --- /dev/null +++ b/interface-definitions/service-event-handler.xml.in @@ -0,0 +1,70 @@ +<?xml version="1.0" encoding="UTF-8"?> +<interfaceDefinition> + <node name="service"> + <children> + <node name="event-handler" owner="${vyos_conf_scripts_dir}/service_event_handler.py"> + <properties> + <help>Service event handler</help> + </properties> + <children> + <tagNode name="event"> + <properties> + <help>Event handler name</help> + </properties> + <children> + <node name="filter"> + <properties> + <help>Logs filter settings</help> + </properties> + <children> + <leafNode name="pattern"> + <properties> + <help>Match pattern (regex)</help> + </properties> + </leafNode> + <leafNode name="syslog-identifier"> + <properties> + <help>Identifier of a process in syslog (string)</help> + </properties> + </leafNode> + </children> + </node> + <node name="script"> + <properties> + <help>Event handler script file</help> + </properties> + <children> + <leafNode name="arguments"> + <properties> + <help>Script arguments</help> + </properties> + </leafNode> + <tagNode name="environment"> + <properties> + <help>Script environment arguments</help> + </properties> + <children> + <leafNode name="value"> + <properties> + <help>Environment value</help> + </properties> + </leafNode> + </children> + </tagNode> + <leafNode name="path"> + <properties> + <help>Path to the script</help> + <constraint> + <validator name="script"/> + </constraint> + </properties> + </leafNode> + </children> + </node> + </children> + </tagNode> + </children> + </node> + </children> + </node> +</interfaceDefinition> diff --git a/src/conf_mode/service_event_handler.py b/src/conf_mode/service_event_handler.py new file mode 100755 index 000000000..23464120b --- /dev/null +++ b/src/conf_mode/service_event_handler.py @@ -0,0 +1,93 @@ +#!/usr/bin/env python3 +# +# Copyright (C) 2023 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 os +import json +from pathlib import Path + +from vyos.config import Config +from vyos.util import call, dict_search +from vyos import ConfigError +from vyos import airbag + +airbag.enable() + +service_name = 'vyos-event-handler' +service_conf = Path(f'/run/{service_name}.conf') + + +def get_config(config=None): + if config: + conf = config + else: + conf = Config() + + base = ['service', 'event-handler', 'event'] + config = conf.get_config_dict(base, + get_first_key=True, + no_tag_node_value_mangle=True) + + return config + + +def verify(config): + # bail out early - looks like removal from running config + if not config: + return None + + for name, event_config in config.items(): + if not dict_search('filter.pattern', event_config) or not dict_search( + 'script.path', event_config): + raise ConfigError( + 'Event-handler: both pattern and script path items are mandatory' + ) + + if dict_search('script.environment.message', event_config): + raise ConfigError( + 'Event-handler: "message" environment variable is reserved for log message text' + ) + + +def generate(config): + if not config: + # Remove old config and return + if os.path.isfile(service_conf): + os.unlink(service_conf) + return None + + # Write configuration file + conf_json = json.dumps(config, indent=4) + service_conf.write_text(conf_json) + + return None + + +def apply(config): + if config: + call(f'systemctl restart {service_name}.service') + else: + call(f'systemctl stop {service_name}.service') + + +if __name__ == '__main__': + try: + c = get_config() + verify(c) + generate(c) + apply(c) + except ConfigError as e: + print(e) + exit(1) diff --git a/src/system/vyos-event-handler.py b/src/system/vyos-event-handler.py new file mode 100755 index 000000000..34f8560f9 --- /dev/null +++ b/src/system/vyos-event-handler.py @@ -0,0 +1,162 @@ +#!/usr/bin/env python3 +# +# Copyright (C) 2023 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) diff --git a/src/systemd/vyos-event-handler.service b/src/systemd/vyos-event-handler.service new file mode 100644 index 000000000..6afe4f95b --- /dev/null +++ b/src/systemd/vyos-event-handler.service @@ -0,0 +1,11 @@ +[Unit] +Description=VyOS event handler +After=network.target vyos-router.service + +[Service] +Type=simple +Restart=always +ExecStart=/usr/bin/python3 /usr/libexec/vyos/system/vyos-event-handler.py --config /run/vyos-event-handler.conf + +[Install] +WantedBy=multi-user.target |