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Diffstat (limited to 'src/python-systemd/journal.py')
| -rw-r--r-- | src/python-systemd/journal.py | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/src/python-systemd/journal.py b/src/python-systemd/journal.py new file mode 100644 index 0000000000..516ca1ab56 --- /dev/null +++ b/src/python-systemd/journal.py @@ -0,0 +1,201 @@ +# -*- Mode: python; indent-tabs-mode: nil -*- */ +# +# This file is part of systemd. +# +# Copyright 2012 David Strauss +# +# systemd 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. +# +# systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>. + +import traceback as _traceback +import os as _os +import logging as _logging +from syslog import (LOG_EMERG, LOG_ALERT, LOG_CRIT, LOG_ERR, + LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG) +from ._journal import sendv, stream_fd + +def _make_line(field, value): + if isinstance(value, bytes): + return field.encode('utf-8') + b'=' + value + else: + return field + '=' + value + +def send(MESSAGE, MESSAGE_ID=None, + CODE_FILE=None, CODE_LINE=None, CODE_FUNC=None, + **kwargs): + r"""Send a message to journald. + + >>> journal.send('Hello world') + >>> journal.send('Hello, again, world', FIELD2='Greetings!') + >>> journal.send('Binary message', BINARY=b'\xde\xad\xbe\xef') + + Value of the MESSAGE argument will be used for the MESSAGE= + field. + + MESSAGE_ID can be given to uniquely identify the type of + message. + + Other parts of the message can be specified as keyword + arguments. + + Both MESSAGE and MESSAGE_ID, if present, must be strings, and + will be sent as UTF-8 to journal. Other arguments can be + bytes, in which case they will be sent as-is to journal. + + CODE_LINE, CODE_FILE, and CODE_FUNC can be specified to + identify the caller. Unless at least on of the three is given, + values are extracted from the stack frame of the caller of + send(). CODE_FILE and CODE_FUNC must be strings, CODE_LINE + must be an integer. + + Other useful fields include PRIORITY, SYSLOG_FACILITY, + SYSLOG_IDENTIFIER, SYSLOG_PID. + """ + + args = ['MESSAGE=' + MESSAGE] + + if MESSAGE_ID is not None: + args.append('MESSAGE_ID=' + MESSAGE_ID) + + if CODE_LINE == CODE_FILE == CODE_FUNC == None: + CODE_FILE, CODE_LINE, CODE_FUNC = \ + _traceback.extract_stack(limit=2)[0][:3] + if CODE_FILE is not None: + args.append('CODE_FILE=' + CODE_FILE) + if CODE_LINE is not None: + args.append('CODE_LINE={:d}'.format(CODE_LINE)) + if CODE_FUNC is not None: + args.append('CODE_FUNC=' + CODE_FUNC) + + args.extend(_make_line(key, val) for key, val in kwargs.items()) + return sendv(*args) + +def stream(identifier, priority=LOG_DEBUG, level_prefix=False): + r"""Return a file object wrapping a stream to journal. + + Log messages written to this file as simple newline sepearted + text strings are written to the journal. + + The file will be line buffered, so messages are actually sent + after a newline character is written. + + >>> stream = journal.stream('myapp') + >>> stream + <open file '<fdopen>', mode 'w' at 0x...> + >>> stream.write('message...\n') + + will produce the following message in the journal: + + PRIORITY=7 + SYSLOG_IDENTIFIER=myapp + MESSAGE=message... + + Using the interface with print might be more convinient: + + >>> from __future__ import print_function + >>> print('message...', file=stream) + + priority is the syslog priority, one of LOG_EMERG, LOG_ALERT, + LOG_CRIT, LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG. + + level_prefix is a boolean. If true, kernel-style log priority + level prefixes (such as '<1>') are interpreted. See + sd-daemon(3) for more information. + """ + + fd = stream_fd(identifier, priority, level_prefix) + return _os.fdopen(fd, 'w', 1) + +class JournalHandler(_logging.Handler): + """Journal handler class for the Python logging framework. + + Please see the Python logging module documentation for an + overview: http://docs.python.org/library/logging.html + + To create a custom logger whose messages go only to journal: + + >>> log = logging.getLogger('custom_logger_name') + >>> log.propagate = False + >>> log.addHandler(journal.JournalHandler()) + >>> log.warn("Some message: %s", detail) + + Note that by default, message levels INFO and DEBUG are ignored + by the logging framework. To enable those log levels: + + >>> log.setLevel(logging.DEBUG) + + To attach journal MESSAGE_ID, an extra field is supported: + + >>> log.warn("Message with ID", + >>> extra={'MESSAGE_ID': '22bb01335f724c959ac4799627d1cb61'}) + + To redirect all logging messages to journal regardless of where + they come from, attach it to the root logger: + + >>> logging.root.addHandler(journal.JournalHandler()) + + For more complex configurations when using dictConfig or + fileConfig, specify 'systemd.journal.JournalHandler' as the + handler class. Only standard handler configuration options + are supported: level, formatter, filters. + + The following journal fields will be sent: + + MESSAGE, PRIORITY, THREAD_NAME, CODE_FILE, CODE_LINE, + CODE_FUNC, LOGGER (name as supplied to getLogger call), + MESSAGE_ID (optional, see above). + """ + + def emit(self, record): + """Write record as journal event. + + MESSAGE is taken from the message provided by the + user, and PRIORITY, LOGGER, THREAD_NAME, + CODE_{FILE,LINE,FUNC} fields are appended + automatically. In addition, record.MESSAGE_ID will be + used if present. + """ + try: + msg = self.format(record) + pri = self.mapPriority(record.levelno) + mid = getattr(record, 'MESSAGE_ID', None) + send(msg, + MESSAGE_ID=mid, + PRIORITY=format(pri), + LOGGER=record.name, + THREAD_NAME=record.threadName, + CODE_FILE=record.pathname, + CODE_LINE=record.lineno, + CODE_FUNC=record.funcName) + except Exception: + self.handleError(record) + + @staticmethod + def mapPriority(levelno): + """Map logging levels to journald priorities. + + Since Python log level numbers are "sparse", we have + to map numbers in between the standard levels too. + """ + if levelno <= _logging.DEBUG: + return LOG_DEBUG + elif levelno <= _logging.INFO: + return LOG_INFO + elif levelno <= _logging.WARNING: + return LOG_WARNING + elif levelno <= _logging.ERROR: + return LOG_ERR + elif levelno <= _logging.CRITICAL: + return LOG_CRIT + else: + return LOG_ALERT |