python/google/appengine/api/logservice/logsutil.py

   1 #!/usr/bin/env python
   2 #
   3 # Copyright 2007 Google Inc.
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #     http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16 #
  17
  18
  19 """Utility methods for working with logs."""
  20
  21
  22 import os
  23 import time
  24
  25
  26
  27 REQUEST_LOG_ID = 'REQUEST_LOG_ID'
  28
  29
  30 _U_SEC = 1000000
  31
  32 LOG_LEVEL_DEBUG = 0
  33 LOG_LEVEL_INFO = 1
  34 LOG_LEVEL_WARNING = 2
  35 LOG_LEVEL_ERROR = 3
  36 LOG_LEVEL_CRITICAL = 4
  37
  38 LOG_LEVELS = [LOG_LEVEL_DEBUG,
  39               LOG_LEVEL_INFO,
  40               LOG_LEVEL_WARNING,
  41               LOG_LEVEL_ERROR,
  42               LOG_LEVEL_CRITICAL]
  43
  44
  45
  46 _DEFAULT_LEVEL = LOG_LEVEL_ERROR
  47
  48
  49 def _CurrentTimeMicro():
  50   return int(time.time() * _U_SEC)
  51
  52
  53 def _Clean(e):
  54   return e.replace('\0', '\n')
  55
  56
  57 def RequestID():
  58   """Returns the ID of the current request assigned by App Engine."""
  59   return os.environ.get(REQUEST_LOG_ID, None)
  60
  61
  62 def _StrictParseLogEntry(entry):
  63   """Parses a single log entry emitted by app_logging.AppLogsHandler.
  64
  65   Parses a log entry of the form LOG <level> <timestamp> <message> where the
  66   level is in the range [0, 4]. If the entry is not of that form, ValueError is
  67   raised.
  68
  69   Args:
  70     entry: The log entry to parse.
  71
  72   Returns:
  73     A (timestamp, level, message) tuple.
  74
  75   Raises:
  76     ValueError: if the entry failed to be parsed.
  77   """
  78   magic, level, timestamp, message = entry.split(' ', 3)
  79   if magic != 'LOG':
  80     raise ValueError()
  81
  82   timestamp, level = int(timestamp), int(level)
  83   if level not in LOG_LEVELS:
  84     raise ValueError()
  85
  86   return timestamp, level, _Clean(message)
  87
  88
  89 def ParseLogEntry(entry):
  90   """Parses a single log entry emitted by app_logging.AppLogsHandler.
  91
  92   Parses a log entry of the form LOG <level> <timestamp> <message> where the
  93   level is in the range [0, 4]. If the entry is not of that form, take the whole
  94   entry to be the message. Null characters in the entry are replaced by
  95   newlines.
  96
  97   Args:
  98     entry: The log entry to parse.
  99
 100   Returns:
 101     A (timestamp, level, message) tuple.
 102   """
 103   try:
 104     return _StrictParseLogEntry(entry)
 105   except ValueError:
 106
 107     return _CurrentTimeMicro(), _DEFAULT_LEVEL, _Clean(entry)
 108
 109
 110 def ParseLogs(logs):
 111   """Parses a str containing newline separated log entries.
 112
 113   Parses a series of log entries in the form LOG <level> <timestamp> <message>
 114   where the level is in the range [0, 4].  Null characters in the entry are
 115   replaced by newlines.
 116
 117   Args:
 118     logs: A string containing the log entries.
 119
 120   Returns:
 121     A list of (timestamp, level, message) tuples.
 122   """
 123   return [ParseLogEntry(line) for line in logs.split('\n') if line]