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1# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5import abc, logging, os, re, time
6import subprocess
7
8import common
9from autotest_lib.client.bin import utils
10from autotest_lib.client.common_lib import error
11from constants import CLEANUP_LOGS_PAUSED_FILE
12
13
14def strip_timestamp(msg):
15    """
16    Strips timestamps and PIDs from a syslog message to facilitate
17    failure reason aggregation when this message is used as an autotest
18    exception text.
19    """
20    kernel = re.search(r' kernel: \[ *\d+.\d+\] (.*)$', msg)
21    if kernel:
22        return 'kernel: ' + kernel.group(1)
23
24    user = re.match(r'[^a-z]+ [^ ]* ([^\[ ]+)(?:\[.*\])?(: .*)$', msg)
25    if user:
26        return user.group(1) + user.group(2)
27
28    logging.warning('Could not parse syslog message: ' + msg)
29    return msg
30
31
32def extract_kernel_timestamp(msg):
33    """Extract a timestmap that appears in kernel log messages and looks
34    like this:
35    ... kernel: [78791.721832] ...
36
37    Returns:
38        The timestamp as float in seconds since last boot.
39    """
40
41    match = re.search('\[\s*([0-9]+\.[0-9]+)\] ', msg)
42    if match:
43        return float(match.group(1))
44    raise error.TestError('Could not extract timestamp from message: ' + msg)
45
46
47class AbstractLogReader(object):
48
49    def __init__(self):
50        self._start_line = 1
51
52    @abc.abstractmethod
53    def read_all_logs(self):
54        """Read all content from log files.
55
56        Generator function.
57        Return an iterator on the content of files.
58
59        This generator can peek a line once (and only once!) by using
60        .send(offset). Must iterate over the peeked line before you can
61        peek again.
62        """
63        pass
64
65    def set_start_by_regexp(self, index, regexp):
66        """Set the start of logs based on a regular expression.
67
68        @param index: line matching regexp to start at, earliest log at 0.
69                Negative numbers indicate matches since end of log.
70        """
71        regexp_compiled = re.compile(regexp)
72        starts = []
73        line_number = 1
74        self._start_line = 1
75        for line in self.read_all_logs():
76            if regexp_compiled.match(line):
77                starts.append(line_number)
78            line_number += 1
79        if index < -len(starts):
80            self._start_line = 1
81        elif index >= len(starts):
82            self._start_line = line_number
83        else:
84            self._start_line = starts[index]
85
86
87    def set_start_by_reboot(self, index):
88        """ Set the start of logs (must be system log) based on reboot.
89
90        @param index: reboot to start at, earliest log at 0.  Negative
91                numbers indicate reboots since end of log.
92        """
93        return self.set_start_by_regexp(index,
94                                        r'.*000\] Linux version \d')
95
96
97    def set_start_by_current(self, relative=0):
98        """ Set start of logs based on current last line.
99
100        @param relative: line relative to current to start at.  1 means
101                to start the log after this line.
102        """
103        count = self._start_line + relative
104        for line in self.read_all_logs():
105            count += 1
106        self._start_line = count
107
108
109    def get_logs(self):
110        """ Get logs since the start line.
111
112        Start line is set by set_start_* functions or
113        since the start of the file if none were called.
114
115        @return string of contents of file since start line.
116        """
117        logs = []
118        for line in self.read_all_logs():
119            logs.append(line)
120        return ''.join(logs)
121
122
123    def can_find(self, string):
124        """ Try to find string in the logs.
125
126        @return boolean indicating if we found the string.
127        """
128        return string in self.get_logs()
129
130
131    def get_last_msg(self, patterns, retries=0, sleep_seconds=0.2):
132        """Search the logs and return the latest occurrence of a message
133        matching one of the patterns.
134
135        Args:
136            patterns: A regexp or a list of regexps to search the logs with.
137                The function returns as soon as it finds any match to one of
138                the patters, it will not search for the other patterns.
139            retries: Number of times to retry if none of the patterns were
140                found. Default is one attempt.
141            sleep_seconds: Time to sleep between retries.
142
143        Returns:
144            The last occurrence of the first matching pattern. "None" if none
145            of the patterns matched.
146        """
147
148        if not type(patterns) in (list, tuple):
149            patterns = [patterns]
150
151        for retry in xrange(retries + 1):
152            for pattern in patterns:
153                regexp_compiled = re.compile(pattern)
154                last_match = None
155                for line in self.read_all_logs():
156                    if regexp_compiled.search(line):
157                        last_match = line
158                if last_match:
159                    return last_match
160            time.sleep(sleep_seconds)
161
162        return None
163
164
165class LogRotationPauser(object):
166    """
167    Class to control when logs are rotated from either server or client.
168
169    Assumes all setting of CLEANUP_LOGS_PAUSED_FILE is done by this class
170    and that all calls to begin and end are properly
171    nested.  For instance, [ a.begin(), b.begin(), b.end(), a.end() ] is
172    supported, but [ a.begin(), b.begin(), a.end(), b.end() ]  is not.
173    We do support redundant calls to the same class, such as
174    [ a.begin(), a.begin(), a.end() ].
175    """
176    def __init__(self, host=None):
177        self._host = host
178        self._begun = False
179        self._is_nested = True
180
181
182    def _run(self, command, *args, **dargs):
183        if self._host:
184            return self._host.run(command, *args, **dargs).exit_status
185        else:
186            return utils.system(command, *args, **dargs)
187
188
189    def begin(self):
190        """Make sure that log rotation is disabled."""
191        if self._begun:
192            return
193        self._is_nested = (self._run(('[ -r %s ]' %
194                                      CLEANUP_LOGS_PAUSED_FILE),
195                                     ignore_status=True) == 0)
196        if self._is_nested:
197            logging.info('File %s was already present' %
198                         CLEANUP_LOGS_PAUSED_FILE)
199        else:
200            self._run('touch ' + CLEANUP_LOGS_PAUSED_FILE)
201        self._begun = True
202
203
204    def end(self):
205        assert self._begun
206        if not self._is_nested:
207            self._run('rm -f ' + CLEANUP_LOGS_PAUSED_FILE)
208        else:
209            logging.info('Leaving existing %s file' % CLEANUP_LOGS_PAUSED_FILE)
210        self._begun = False
211
212
213class LogReader(AbstractLogReader):
214    """Class to read traditional text log files.
215
216    Be default reads all logs from /var/log/messages.
217    """
218
219    def __init__(self, filename='/var/log/messages', include_rotated_logs=True):
220        AbstractLogReader.__init__(self)
221        self._filename = filename
222        self._include_rotated_logs = include_rotated_logs
223        if not os.path.exists(CLEANUP_LOGS_PAUSED_FILE):
224            raise error.TestError('LogReader created without ' +
225                                  CLEANUP_LOGS_PAUSED_FILE)
226
227    def read_all_logs(self):
228        log_files = []
229        line_number = 0
230        if self._include_rotated_logs:
231            log_files.extend(utils.system_output(
232                'ls -tr1 %s.*' % self._filename,
233                ignore_status=True).splitlines())
234        log_files.append(self._filename)
235        for log_file in log_files:
236            f = open(log_file)
237            for line in f:
238                line_number += 1
239                if line_number < self._start_line:
240                    continue
241                peek = yield line
242                if peek:
243                  buf = [f.next() for _ in xrange(peek)]
244                  yield buf[-1]
245                  while buf:
246                    yield buf.pop(0)
247            f.close()
248
249
250class JournalLogReader(AbstractLogReader):
251    """A class to read logs stored by systemd-journald.
252    """
253
254    def read_all_logs(self):
255      proc = subprocess.Popen(['journalctl'], stdout=subprocess.PIPE)
256      line_number = 0
257      for line in proc.stdout:
258          line_number += 1
259          if line_number < self._start_line:
260              continue
261          yield line
262      proc.terminate()
263
264def make_system_log_reader():
265    """Create a system log reader.
266
267    This will create JournalLogReader() or LogReader() depending on
268    whether the system is configured with systemd.
269    """
270    if os.path.exists("/var/log/journal"):
271        return JournalLogReader()
272    else:
273        return LogReader()
274