1 # -*- Mode: python; indent-tabs-mode: nil -*- */
3 # This file is part of systemd.
5 # Copyright 2012 David Strauss
7 # systemd is free software; you can redistribute it and/or modify it
8 # under the terms of the GNU Lesser General Public License as published by
9 # the Free Software Foundation; either version 2.1 of the License, or
10 # (at your option) any later version.
12 # systemd is distributed in the hope that it will be useful, but
13 # WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 # Lesser General Public License for more details.
17 # You should have received a copy of the GNU Lesser General Public License
18 # along with systemd; If not, see <http://www.gnu.org/licenses/>.
20 import traceback as _traceback
22 import logging as _logging
23 from syslog import (LOG_EMERG, LOG_ALERT, LOG_CRIT, LOG_ERR,
24 LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG)
25 from ._journal import sendv, stream_fd
27 def _make_line(field, value):
28 if isinstance(value, bytes):
29 return field.encode('utf-8') + b'=' + value
31 return field + '=' + value
33 def send(MESSAGE, MESSAGE_ID=None,
34 CODE_FILE=None, CODE_LINE=None, CODE_FUNC=None,
36 r"""Send a message to journald.
38 >>> journal.send('Hello world')
39 >>> journal.send('Hello, again, world', FIELD2='Greetings!')
40 >>> journal.send('Binary message', BINARY=b'\xde\xad\xbe\xef')
42 Value of the MESSAGE argument will be used for the MESSAGE=
45 MESSAGE_ID can be given to uniquely identify the type of
48 Other parts of the message can be specified as keyword
51 Both MESSAGE and MESSAGE_ID, if present, must be strings, and
52 will be sent as UTF-8 to journal. Other arguments can be
53 bytes, in which case they will be sent as-is to journal.
55 CODE_LINE, CODE_FILE, and CODE_FUNC can be specified to
56 identify the caller. Unless at least on of the three is given,
57 values are extracted from the stack frame of the caller of
58 send(). CODE_FILE and CODE_FUNC must be strings, CODE_LINE
61 Other useful fields include PRIORITY, SYSLOG_FACILITY,
62 SYSLOG_IDENTIFIER, SYSLOG_PID.
65 args = ['MESSAGE=' + MESSAGE]
67 if MESSAGE_ID is not None:
68 args.append('MESSAGE_ID=' + MESSAGE_ID)
70 if CODE_LINE == CODE_FILE == CODE_FUNC == None:
71 CODE_FILE, CODE_LINE, CODE_FUNC = \
72 _traceback.extract_stack(limit=2)[0][:3]
73 if CODE_FILE is not None:
74 args.append('CODE_FILE=' + CODE_FILE)
75 if CODE_LINE is not None:
76 args.append('CODE_LINE={:d}'.format(CODE_LINE))
77 if CODE_FUNC is not None:
78 args.append('CODE_FUNC=' + CODE_FUNC)
80 args.extend(_make_line(key, val) for key, val in kwargs.items())
83 def stream(identifier, priority=LOG_DEBUG, level_prefix=False):
84 r"""Return a file object wrapping a stream to journal.
86 Log messages written to this file as simple newline sepearted
87 text strings are written to the journal.
89 The file will be line buffered, so messages are actually sent
90 after a newline character is written.
92 >>> stream = journal.stream('myapp')
94 <open file '<fdopen>', mode 'w' at 0x...>
95 >>> stream.write('message...\n')
97 will produce the following message in the journal:
100 SYSLOG_IDENTIFIER=myapp
103 Using the interface with print might be more convinient:
105 >>> from __future__ import print_function
106 >>> print('message...', file=stream)
108 priority is the syslog priority, one of LOG_EMERG, LOG_ALERT,
109 LOG_CRIT, LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG.
111 level_prefix is a boolean. If true, kernel-style log priority
112 level prefixes (such as '<1>') are interpreted. See
113 sd-daemon(3) for more information.
116 fd = stream_fd(identifier, priority, level_prefix)
117 return _os.fdopen(fd, 'w', 1)
119 class JournalHandler(_logging.Handler):
120 """Journal handler class for the Python logging framework.
122 Please see the Python logging module documentation for an
123 overview: http://docs.python.org/library/logging.html
125 To create a custom logger whose messages go only to journal:
127 >>> log = logging.getLogger('custom_logger_name')
128 >>> log.propagate = False
129 >>> log.addHandler(journal.JournalHandler())
130 >>> log.warn("Some message: %s", detail)
132 Note that by default, message levels INFO and DEBUG are ignored
133 by the logging framework. To enable those log levels:
135 >>> log.setLevel(logging.DEBUG)
137 To attach journal MESSAGE_ID, an extra field is supported:
139 >>> log.warn("Message with ID",
140 >>> extra={'MESSAGE_ID': '22bb01335f724c959ac4799627d1cb61'})
142 To redirect all logging messages to journal regardless of where
143 they come from, attach it to the root logger:
145 >>> logging.root.addHandler(journal.JournalHandler())
147 For more complex configurations when using dictConfig or
148 fileConfig, specify 'systemd.journal.JournalHandler' as the
149 handler class. Only standard handler configuration options
150 are supported: level, formatter, filters.
152 The following journal fields will be sent:
154 MESSAGE, PRIORITY, THREAD_NAME, CODE_FILE, CODE_LINE,
155 CODE_FUNC, LOGGER (name as supplied to getLogger call),
156 MESSAGE_ID (optional, see above).
159 def emit(self, record):
160 """Write record as journal event.
162 MESSAGE is taken from the message provided by the
163 user, and PRIORITY, LOGGER, THREAD_NAME,
164 CODE_{FILE,LINE,FUNC} fields are appended
165 automatically. In addition, record.MESSAGE_ID will be
169 msg = self.format(record)
170 pri = self.mapPriority(record.levelno)
171 mid = getattr(record, 'MESSAGE_ID', None)
174 PRIORITY=format(pri),
176 THREAD_NAME=record.threadName,
177 CODE_FILE=record.pathname,
178 CODE_LINE=record.lineno,
179 CODE_FUNC=record.funcName)
181 self.handleError(record)
184 def mapPriority(levelno):
185 """Map logging levels to journald priorities.
187 Since Python log level numbers are "sparse", we have
188 to map numbers in between the standard levels too.
190 if levelno <= _logging.DEBUG:
192 elif levelno <= _logging.INFO:
194 elif levelno <= _logging.WARNING:
196 elif levelno <= _logging.ERROR:
198 elif levelno <= _logging.CRITICAL: