How to redirect python warnings to a custom stream?

Question

Let's say I have a file-like object like StreamIO and want the python's warning module write all warning messages to it. How do I do that?

Answer 1

Try reassigning warnings.showwarning i.e.

#!/sw/bin/python2.5

import warnings, sys

def customwarn(message, category, filename, lineno, file=None, line=None):
    sys.stdout.write(warnings.formatwarning(message, category, filename, lineno))

warnings.showwarning = customwarn
warnings.warn("test warning")

will redirect all warnings to stdout.