tools/helpers/logging.py

   1 # Copyright 2021 Oliver Smith
   2 # SPDX-License-Identifier: GPL-3.0-or-later
   3 import logging
   4 import os
   5 import sys
   6
   7
   8 class log_handler(logging.StreamHandler):
   9     """
  10     Write to stdout and to the already opened log file.
  11     """
  12     _args = None
  13
  14     def emit(self, record):
  15         try:
  16             msg = self.format(record)
  17
  18             # INFO or higher: Write to stdout
  19             if (not self._args.details_to_stdout and
  20                 not self._args.quiet and
  21                     record.levelno >= logging.INFO):
  22                 stream = self.stream
  23                 stream.write(msg)
  24                 stream.write(self.terminator)
  25                 self.flush()
  26
  27             # Everything: Write to logfd
  28             msg = "(" + str(os.getpid()).zfill(6) + ") " + msg
  29             self._args.logfd.write(msg + "\n")
  30             self._args.logfd.flush()
  31
  32         except (KeyboardInterrupt, SystemExit):
  33             raise
  34         except BaseException:
  35             self.handleError(record)
  36
  37
  38 def add_verbose_log_level():
  39     """
  40     Add a new log level "verbose", which is below "debug". Also monkeypatch
  41     logging, so it can be used with logging.verbose().
  42
  43     This function is based on work by Voitek Zylinski and sleepycal:
  44     https://stackoverflow.com/a/20602183
  45     All stackoverflow user contributions are licensed as CC-BY-SA:
  46     https://creativecommons.org/licenses/by-sa/3.0/
  47     """
  48     logging.VERBOSE = 5
  49     logging.addLevelName(logging.VERBOSE, "VERBOSE")
  50     logging.Logger.verbose = lambda inst, msg, * \
  51         args, **kwargs: inst.log(logging.VERBOSE, msg, *args, **kwargs)
  52     logging.verbose = lambda msg, *args, **kwargs: logging.log(logging.VERBOSE,
  53                                                                msg, *args,
  54                                                                **kwargs)
  55
  56
  57 def init(args):
  58     """
  59     Set log format and add the log file descriptor to args.logfd, add the
  60     verbose log level.
  61     """
  62     # Set log file descriptor (logfd)
  63     if args.details_to_stdout:
  64         setattr(args, "logfd", sys.stdout)
  65     else:
  66         # Require containing directory to exist (so we don't create the work
  67         # folder and break the folder migration logic, which needs to set the
  68         # version upon creation)
  69         dir = os.path.dirname(args.log)
  70         if os.path.exists(dir):
  71             setattr(args, "logfd", open(args.log, "a+"))
  72         else:
  73             setattr(args, "logfd", open(os.devnull, "a+"))
  74             if args.action != "init":
  75                 print("WARNING: Can't create log file in '" + dir + "', path"
  76                       " does not exist!")
  77
  78     # Set log format
  79     root_logger = logging.getLogger()
  80     root_logger.handlers = []
  81     formatter = logging.Formatter("[%(asctime)s] %(message)s",
  82                                   datefmt="%H:%M:%S")
  83
  84     # Set log level
  85     add_verbose_log_level()
  86     root_logger.setLevel(logging.DEBUG)
  87     if args.verbose:
  88         root_logger.setLevel(logging.VERBOSE)
  89
  90     # Add a custom log handler
  91     handler = log_handler()
  92     log_handler._args = args
  93     handler.setFormatter(formatter)
  94     root_logger.addHandler(handler)
  95
  96
  97 def disable():
  98     logger = logging.getLogger()
  99     logger.disabled = True