diff options
Diffstat (limited to 'src')
| -rwxr-xr-x | src/conf_mode/service_event_handler.py | 91 | ||||
| -rwxr-xr-x | src/system/vyos-event-handler.py | 160 | ||||
| -rw-r--r-- | src/systemd/vyos-event-handler.service | 11 | 
3 files changed, 262 insertions, 0 deletions
| diff --git a/src/conf_mode/service_event_handler.py b/src/conf_mode/service_event_handler.py new file mode 100755 index 000000000..5440d1056 --- /dev/null +++ b/src/conf_mode/service_event_handler.py @@ -0,0 +1,91 @@ +#!/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 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 +        service_conf.unlink(missing_ok=True) +        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..691f674b2 --- /dev/null +++ b/src/system/vyos-event-handler.py @@ -0,0 +1,160 @@ +#!/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 select +import re +import json +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 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 = 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 | 
