mirror of https://github.com/cool-RR/PySnooper.git
87 lines
2.6 KiB
Python
87 lines
2.6 KiB
Python
# Copyright 2019 Ram Rachum and collaborators.
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# This program is distributed under the MIT license.
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import sys
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from .third_party import decorator
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from . import utils
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from . import pycompat
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from .tracer import Tracer
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def get_write_and_truncate_functions(output):
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if output is None:
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def write(s):
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stderr = sys.stderr
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try:
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stderr.write(s)
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except UnicodeEncodeError:
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# God damn Python 2
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stderr.write(utils.shitcode(s))
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truncate = None
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elif isinstance(output, (pycompat.PathLike, str)):
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def write(s):
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with open(output, 'a') as output_file:
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output_file.write(s)
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def truncate():
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with open(output, 'w') as output_file:
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pass
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elif callable(output):
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write = output
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truncate = None
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else:
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assert isinstance(output, utils.WritableStream)
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def write(s):
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output.write(s)
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truncate = None
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return (write, truncate)
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def snoop(output=None, variables=(), exploded_variables=(), depth=1, prefix='', overwrite=False):
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'''
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Snoop on the function, writing everything it's doing to stderr.
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This is useful for debugging.
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When you decorate a function with `@pysnooper.snoop()`, you'll get a log of
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every line that ran in the function and a play-by-play of every local
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variable that changed.
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If stderr is not easily accessible for you, you can redirect the output to
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a file::
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@pysnooper.snoop('/my/log/file.log')
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See values of some variables that aren't local variables::
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@pysnooper.snoop(variables=('foo.bar', 'self.whatever'))
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Show snoop lines for functions that your function calls::
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@pysnooper.snoop(depth=2)
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Start all snoop lines with a prefix, to grep for them easily::
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@pysnooper.snoop(prefix='ZZZ ')
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'''
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write, truncate = get_write_and_truncate_functions(output)
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if truncate is None and overwrite:
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raise Exception("`overwrite=True` can only be used when writing "
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"content to file.")
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def decorate(function):
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target_code_object = function.__code__
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tracer = Tracer(target_code_object=target_code_object, write=write,
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truncate=truncate, variables=variables, depth=depth,
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prefix=prefix, overwrite=overwrite,
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exploded_variables=exploded_variables)
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def inner(function_, *args, **kwargs):
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with tracer:
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return function(*args, **kwargs)
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return decorator.decorate(function, inner)
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return decorate
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