1"""A simple log mechanism styled after PEP 282."""
2
3# The class here is styled after PEP 282 so that it could later be
4# replaced with a standard Python logging implementation.
5
6DEBUG = 1
7INFO = 2
8WARN = 3
9ERROR = 4
10FATAL = 5
11
12import sys
13
14class Log:
15
16    def __init__(self, threshold=WARN):
17        self.threshold = threshold
18
19    def _log(self, level, msg, args):
20        if level not in (DEBUG, INFO, WARN, ERROR, FATAL):
21            raise ValueError('%s wrong log level' % str(level))
22
23        if level >= self.threshold:
24            if args:
25                msg = msg % args
26            if level in (WARN, ERROR, FATAL):
27                stream = sys.stderr
28            else:
29                stream = sys.stdout
30            if stream.errors == 'strict':
31                # emulate backslashreplace error handler
32                encoding = stream.encoding
33                msg = msg.encode(encoding, "backslashreplace").decode(encoding)
34            stream.write('%s\n' % msg)
35            stream.flush()
36
37    def log(self, level, msg, *args):
38        self._log(level, msg, args)
39
40    def debug(self, msg, *args):
41        self._log(DEBUG, msg, args)
42
43    def info(self, msg, *args):
44        self._log(INFO, msg, args)
45
46    def warn(self, msg, *args):
47        self._log(WARN, msg, args)
48
49    def error(self, msg, *args):
50        self._log(ERROR, msg, args)
51
52    def fatal(self, msg, *args):
53        self._log(FATAL, msg, args)
54
55_global_log = Log()
56log = _global_log.log
57debug = _global_log.debug
58info = _global_log.info
59warn = _global_log.warn
60error = _global_log.error
61fatal = _global_log.fatal
62
63def set_threshold(level):
64    # return the old threshold for use from tests
65    old = _global_log.threshold
66    _global_log.threshold = level
67    return old
68
69def set_verbosity(v):
70    if v <= 0:
71        set_threshold(WARN)
72    elif v == 1:
73        set_threshold(INFO)
74    elif v >= 2:
75        set_threshold(DEBUG)
76