root / lib / utils / log.py @ 7ee045a0
History | View | Annotate | Download (8.4 kB)
1 |
#
|
---|---|
2 |
#
|
3 |
|
4 |
# Copyright (C) 2006, 2007, 2010, 2011 Google Inc.
|
5 |
#
|
6 |
# This program is free software; you can redistribute it and/or modify
|
7 |
# it under the terms of the GNU General Public License as published by
|
8 |
# the Free Software Foundation; either version 2 of the License, or
|
9 |
# (at your option) any later version.
|
10 |
#
|
11 |
# This program is distributed in the hope that it will be useful, but
|
12 |
# WITHOUT ANY WARRANTY; without even the implied warranty of
|
13 |
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
14 |
# General Public License for more details.
|
15 |
#
|
16 |
# You should have received a copy of the GNU General Public License
|
17 |
# along with this program; if not, write to the Free Software
|
18 |
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
19 |
# 02110-1301, USA.
|
20 |
|
21 |
"""Utility functions for logging.
|
22 |
|
23 |
"""
|
24 |
|
25 |
import os.path |
26 |
import logging |
27 |
import logging.handlers |
28 |
|
29 |
from ganeti import constants |
30 |
from ganeti import compat |
31 |
|
32 |
|
33 |
class _ReopenableLogHandler(logging.handlers.BaseRotatingHandler): |
34 |
"""Log handler with ability to reopen log file on request.
|
35 |
|
36 |
In combination with a SIGHUP handler this class can reopen the log file on
|
37 |
user request.
|
38 |
|
39 |
"""
|
40 |
def __init__(self, filename): |
41 |
"""Initializes this class.
|
42 |
|
43 |
@type filename: string
|
44 |
@param filename: Path to logfile
|
45 |
|
46 |
"""
|
47 |
logging.handlers.BaseRotatingHandler.__init__(self, filename, "a") |
48 |
|
49 |
assert self.encoding is None, "Encoding not supported for logging" |
50 |
assert not hasattr(self, "_reopen"), "Base class has '_reopen' attribute" |
51 |
|
52 |
self._reopen = False |
53 |
|
54 |
def shouldRollover(self, _): # pylint: disable-msg=C0103 |
55 |
"""Determine whether log file should be reopened.
|
56 |
|
57 |
"""
|
58 |
return self._reopen or not self.stream |
59 |
|
60 |
def doRollover(self): # pylint: disable-msg=C0103 |
61 |
"""Reopens the log file.
|
62 |
|
63 |
"""
|
64 |
if self.stream: |
65 |
self.stream.flush()
|
66 |
self.stream.close()
|
67 |
self.stream = None |
68 |
|
69 |
# Reopen file
|
70 |
# TODO: Handle errors?
|
71 |
self.stream = open(self.baseFilename, "a") |
72 |
|
73 |
def RequestReopen(self): |
74 |
"""Register a request to reopen the file.
|
75 |
|
76 |
The file will be reopened before writing the next log record.
|
77 |
|
78 |
"""
|
79 |
self._reopen = True |
80 |
|
81 |
|
82 |
def _LogErrorsToConsole(base): |
83 |
"""Create wrapper class writing errors to console.
|
84 |
|
85 |
This needs to be in a function for unittesting.
|
86 |
|
87 |
"""
|
88 |
class wrapped(base): # pylint: disable-msg=C0103 |
89 |
"""Log handler that doesn't fallback to stderr.
|
90 |
|
91 |
When an error occurs while writing on the logfile, logging.FileHandler
|
92 |
tries to log on stderr. This doesn't work in Ganeti since stderr is
|
93 |
redirected to a logfile. This class avoids failures by reporting errors to
|
94 |
/dev/console.
|
95 |
|
96 |
"""
|
97 |
def __init__(self, console, *args, **kwargs): |
98 |
"""Initializes this class.
|
99 |
|
100 |
@type console: file-like object or None
|
101 |
@param console: Open file-like object for console
|
102 |
|
103 |
"""
|
104 |
base.__init__(self, *args, **kwargs)
|
105 |
assert not hasattr(self, "_console") |
106 |
self._console = console
|
107 |
|
108 |
def handleError(self, record): # pylint: disable-msg=C0103 |
109 |
"""Handle errors which occur during an emit() call.
|
110 |
|
111 |
Try to handle errors with FileHandler method, if it fails write to
|
112 |
/dev/console.
|
113 |
|
114 |
"""
|
115 |
try:
|
116 |
base.handleError(record) |
117 |
except Exception: # pylint: disable-msg=W0703 |
118 |
if self._console: |
119 |
try:
|
120 |
# Ignore warning about "self.format", pylint: disable-msg=E1101
|
121 |
self._console.write("Cannot log message:\n%s\n" % |
122 |
self.format(record))
|
123 |
except Exception: # pylint: disable-msg=W0703 |
124 |
# Log handler tried everything it could, now just give up
|
125 |
pass
|
126 |
|
127 |
return wrapped
|
128 |
|
129 |
|
130 |
#: Custom log handler for writing to console with a reopenable handler
|
131 |
_LogHandler = _LogErrorsToConsole(_ReopenableLogHandler) |
132 |
|
133 |
|
134 |
def _GetLogFormatter(program, multithreaded, debug, syslog): |
135 |
"""Build log formatter.
|
136 |
|
137 |
@param program: Program name
|
138 |
@param multithreaded: Whether to add thread name to log messages
|
139 |
@param debug: Whether to enable debug messages
|
140 |
@param syslog: Whether the formatter will be used for syslog
|
141 |
|
142 |
"""
|
143 |
parts = [] |
144 |
|
145 |
if syslog:
|
146 |
parts.append(program + "[%(process)d]:")
|
147 |
else:
|
148 |
parts.append("%(asctime)s: " + program + " pid=%(process)d") |
149 |
|
150 |
if multithreaded:
|
151 |
if syslog:
|
152 |
parts.append(" (%(threadName)s)")
|
153 |
else:
|
154 |
parts.append("/%(threadName)s")
|
155 |
|
156 |
# Add debug info for non-syslog loggers
|
157 |
if debug and not syslog: |
158 |
parts.append(" %(module)s:%(lineno)s")
|
159 |
|
160 |
# Ses, we do want the textual level, as remote syslog will probably lose the
|
161 |
# error level, and it's easier to grep for it.
|
162 |
parts.append(" %(levelname)s %(message)s")
|
163 |
|
164 |
return logging.Formatter("".join(parts)) |
165 |
|
166 |
|
167 |
def _ReopenLogFiles(handlers): |
168 |
"""Wrapper for reopening all log handler's files in a sequence.
|
169 |
|
170 |
"""
|
171 |
for handler in handlers: |
172 |
handler.RequestReopen() |
173 |
logging.info("Received request to reopen log files")
|
174 |
|
175 |
|
176 |
def SetupLogging(logfile, program, debug=0, stderr_logging=False, |
177 |
multithreaded=False, syslog=constants.SYSLOG_USAGE,
|
178 |
console_logging=False, root_logger=None): |
179 |
"""Configures the logging module.
|
180 |
|
181 |
@type logfile: str
|
182 |
@param logfile: the filename to which we should log
|
183 |
@type program: str
|
184 |
@param program: the name under which we should log messages
|
185 |
@type debug: integer
|
186 |
@param debug: if greater than zero, enable debug messages, otherwise
|
187 |
only those at C{INFO} and above level
|
188 |
@type stderr_logging: boolean
|
189 |
@param stderr_logging: whether we should also log to the standard error
|
190 |
@type multithreaded: boolean
|
191 |
@param multithreaded: if True, will add the thread name to the log file
|
192 |
@type syslog: string
|
193 |
@param syslog: one of 'no', 'yes', 'only':
|
194 |
- if no, syslog is not used
|
195 |
- if yes, syslog is used (in addition to file-logging)
|
196 |
- if only, only syslog is used
|
197 |
@type console_logging: boolean
|
198 |
@param console_logging: if True, will use a FileHandler which falls back to
|
199 |
the system console if logging fails
|
200 |
@type root_logger: logging.Logger
|
201 |
@param root_logger: Root logger to use (for unittests)
|
202 |
@raise EnvironmentError: if we can't open the log file and
|
203 |
syslog/stderr logging is disabled
|
204 |
@rtype: callable
|
205 |
@return: Function reopening all open log files when called
|
206 |
|
207 |
"""
|
208 |
progname = os.path.basename(program) |
209 |
|
210 |
formatter = _GetLogFormatter(progname, multithreaded, debug, False)
|
211 |
syslog_fmt = _GetLogFormatter(progname, multithreaded, debug, True)
|
212 |
|
213 |
reopen_handlers = [] |
214 |
|
215 |
if root_logger is None: |
216 |
root_logger = logging.getLogger("")
|
217 |
root_logger.setLevel(logging.NOTSET) |
218 |
|
219 |
# Remove all previously setup handlers
|
220 |
for handler in root_logger.handlers: |
221 |
handler.close() |
222 |
root_logger.removeHandler(handler) |
223 |
|
224 |
if stderr_logging:
|
225 |
stderr_handler = logging.StreamHandler() |
226 |
stderr_handler.setFormatter(formatter) |
227 |
if debug:
|
228 |
stderr_handler.setLevel(logging.NOTSET) |
229 |
else:
|
230 |
stderr_handler.setLevel(logging.CRITICAL) |
231 |
root_logger.addHandler(stderr_handler) |
232 |
|
233 |
if syslog in (constants.SYSLOG_YES, constants.SYSLOG_ONLY): |
234 |
facility = logging.handlers.SysLogHandler.LOG_DAEMON |
235 |
syslog_handler = logging.handlers.SysLogHandler(constants.SYSLOG_SOCKET, |
236 |
facility) |
237 |
syslog_handler.setFormatter(syslog_fmt) |
238 |
# Never enable debug over syslog
|
239 |
syslog_handler.setLevel(logging.INFO) |
240 |
root_logger.addHandler(syslog_handler) |
241 |
|
242 |
if syslog != constants.SYSLOG_ONLY:
|
243 |
# this can fail, if the logging directories are not setup or we have
|
244 |
# a permisssion problem; in this case, it's best to log but ignore
|
245 |
# the error if stderr_logging is True, and if false we re-raise the
|
246 |
# exception since otherwise we could run but without any logs at all
|
247 |
try:
|
248 |
if console_logging:
|
249 |
logfile_handler = _LogHandler(open(constants.DEV_CONSOLE, "a"), |
250 |
logfile) |
251 |
else:
|
252 |
logfile_handler = _ReopenableLogHandler(logfile) |
253 |
|
254 |
logfile_handler.setFormatter(formatter) |
255 |
if debug:
|
256 |
logfile_handler.setLevel(logging.DEBUG) |
257 |
else:
|
258 |
logfile_handler.setLevel(logging.INFO) |
259 |
root_logger.addHandler(logfile_handler) |
260 |
reopen_handlers.append(logfile_handler) |
261 |
except EnvironmentError: |
262 |
if stderr_logging or syslog == constants.SYSLOG_YES: |
263 |
logging.exception("Failed to enable logging to file '%s'", logfile)
|
264 |
else:
|
265 |
# we need to re-raise the exception
|
266 |
raise
|
267 |
|
268 |
return compat.partial(_ReopenLogFiles, reopen_handlers)
|