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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            try:
31                stream.write('%s\n' % msg)
32            except UnicodeEncodeError:
33                # emulate backslashreplace error handler
34                encoding = stream.encoding
35                msg = msg.encode(encoding, "backslashreplace").decode(encoding)
36                stream.write('%s\n' % msg)
37            stream.flush()
38
39    def log(self, level, msg, *args):
40        self._log(level, msg, args)
41
42    def debug(self, msg, *args):
43        self._log(DEBUG, msg, args)
44
45    def info(self, msg, *args):
46        self._log(INFO, msg, args)
47
48    def warn(self, msg, *args):
49        self._log(WARN, msg, args)
50
51    def error(self, msg, *args):
52        self._log(ERROR, msg, args)
53
54    def fatal(self, msg, *args):
55        self._log(FATAL, msg, args)
56
57_global_log = Log()
58log = _global_log.log
59debug = _global_log.debug
60info = _global_log.info
61warn = _global_log.warn
62error = _global_log.error
63fatal = _global_log.fatal
64
65def set_threshold(level):
66    # return the old threshold for use from tests
67    old = _global_log.threshold
68    _global_log.threshold = level
69    return old
70
71def set_verbosity(v):
72    if v <= 0:
73        set_threshold(WARN)
74    elif v == 1:
75        set_threshold(INFO)
76    elif v >= 2:
77        set_threshold(DEBUG)
78