airbag: T2186: generic syslog

1 files changed, 143 insertions, 0 deletions

diff --git a/python/vyos/logger.py b/python/vyos/logger.py
new file mode 100644
index 000000000..f7cc964d5
--- /dev/null
+++ b/python/vyos/logger.py
@@ -0,0 +1,143 @@
+# Copyright 2020 VyOS maintainers and contributors <maintainers@vyos.io>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library 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
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this library.  If not, see <http://www.gnu.org/licenses/>.
+
+# A wrapper class around logging to make it easier to use
+
+# for a syslog logger:
+# from vyos.logger import syslog
+# syslog.critical('message')
+
+# for a stderr logger:
+# from vyos.logger import stderr
+# stderr.critical('message')
+
+# for a custom logger (syslog and file):
+# from vyos.logger import getLogger
+# combined = getLogger(__name__, syslog=True, stream=sys.stdout, filename='/tmp/test')
+# combined.critical('message')
+
+import sys
+import logging
+import logging.handlers as handlers
+
+TIMED = '%(asctime)s: %(message)s'
+SHORT = '%(filename)s: %(message)s'
+CLEAR = '%(levelname) %(asctime)s %(filename)s: %(message)s'
+
+_levels = {
+    'CRITICAL': logging.CRITICAL,
+   	'ERROR': logging.CRITICAL,
+   	'WARNING': logging.WARNING,
+   	'INFO': logging.INFO,
+   	'DEBUG': logging.DEBUG,
+   	'NOTSET': logging.NOTSET,
+}
+
+# prevent recreation of already created logger
+_created = {}
+
+def getLogger(name=None, **kwargs):
+	if name in _created:
+		if len(kwargs) == 0:
+			return _created[name]
+		raise ValueError('a logger with the name "{name} already exists')
+
+	logger = logging.getLogger(name)
+	logger.setLevel(_levels[kwargs.get('level', 'DEBUG')])
+
+	if 'address' in kwargs or kwargs.get('syslog', False):
+		logger.addHandler(_syslog(**kwargs))
+	if 'stream' in kwargs:
+		logger.addHandler(_stream(**kwargs))
+	if 'filename' in kwargs:
+		logger.addHandler(_file(**kwargs))
+
+	_created[name] = logger
+	return logger
+
+
+def _syslog(**kwargs):
+	formating = kwargs.get('format', SHORT)
+	handler = handlers.SysLogHandler(
+		address=kwargs.get('address', '/dev/log'),
+		facility=kwargs.get('facility', 'syslog'),
+	)
+	handler.setFormatter(logging.Formatter(formating))
+	return handler
+
+
+def _stream(**kwargs):
+	formating = kwargs.get('format', CLEAR)
+	handler = logging.StreamHandler(
+		stream=kwargs.get('stream', sys.stderr),
+	)
+	handler.setFormatter(logging.Formatter(formating))
+	return handler
+
+
+def _file(**kwargs):
+	formating = kwargs.get('format', CLEAR)
+	handler = handlers.RotatingFileHandler(
+		filename=kwargs.get('filename', 1048576),
+		maxBytes=kwargs.get('maxBytes', 1048576),
+		backupCount=kwargs.get('backupCount', 3),
+	)
+	handler.setFormatter(logging.Formatter(formating))
+	return handler
+
+
+# exported pre-built logger, please keep in mind that the names
+# must be unique otherwise the logger are shared
+
+# a logger for stderr
+stderr = getLogger(
+	'VyOS Syslog',
+	format=SHORT,
+	stream=sys.stderr,
+	address='/dev/log'
+)
+
+# a logger to syslog
+syslog = getLogger(
+	'VyOS StdErr',
+	format='%(message)s',
+	address='/dev/log'
+)
+
+
+# testing
+if __name__ == '__main__':
+	# from vyos.logger import getLogger
+	formating = '%(asctime)s (%(filename)s) %(levelname)s: %(message)s'
+
+	# syslog logger
+	# syslog=True if no 'address' field is provided
+	syslog = getLogger(__name__ + '.1', syslog=True, format=formating)
+	syslog.info('syslog test')
+
+	# steam logger
+	stream = getLogger(__name__ + '.2', stream=sys.stdout, level='ERROR')
+	stream.info('steam test')
+
+	# file logger
+	filelog = getLogger(__name__ + '.3', filename='/tmp/test')
+	filelog.info('file test')
+
+	# create a combined logger
+	getLogger('VyOS', syslog=True, stream=sys.stdout, filename='/tmp/test')
+
+	# recover the created logger from name
+	combined = getLogger('VyOS')
+	combined.info('combined test')