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-rwxr-xr-xsrc/system/vyos-event-handler.py120
1 files changed, 120 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..f4b793dbe
--- /dev/null
+++ b/src/system/vyos-event-handler.py
@@ -0,0 +1,120 @@
+#!/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
+from pathlib import Path
+from signal import signal, SIGTERM, SIGINT
+from systemd import journal
+from sys import exit
+from vyos.util import call
+
+# 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)
+
+
+# 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'])
+
+
+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())
+ 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())
+
+ # 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)
+
+ 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:
+ analyze_message(message, patterns)