python warnings.warn test

chenlijun@redis00 /tmp/test_warn $ python tmp.py
see each key the first time
  File "tmp.py", line 5, in <module>
    func1("aaa")
  File "/tmp/test_warn/app_code.py", line 5, in func1
    get1(val)
  File "/tmp/test_warn/fake_libmc.py", line 14, in get1
    warnings.warn(val)
  File "/tmp/test_warn/fake_libmc.py", line 7, in warn_with_traceback
    traceback.print_stack(file=log)
/tmp/test_warn/fake_libmc.py:14: UserWarning: aaa
  warnings.warn(val)
  File "tmp.py", line 6, in <module>
    func1("bbb")
  File "/tmp/test_warn/app_code.py", line 5, in func1
    get1(val)
  File "/tmp/test_warn/fake_libmc.py", line 14, in get1
    warnings.warn(val)
  File "/tmp/test_warn/fake_libmc.py", line 7, in warn_with_traceback
    traceback.print_stack(file=log)
/tmp/test_warn/fake_libmc.py:14: UserWarning: bbb
  warnings.warn(val)
see each key the second time
see each key the third time, diff source code
  File "tmp.py", line 13, in <module>
    func2("aaa")
  File "/tmp/test_warn/app_code.py", line 9, in func2
    get2(val)
  File "/tmp/test_warn/fake_libmc.py", line 18, in get2
    warnings.warn(val)
  File "/tmp/test_warn/fake_libmc.py", line 7, in warn_with_traceback
    traceback.print_stack(file=log)
/tmp/test_warn/fake_libmc.py:18: UserWarning: aaa
  warnings.warn(val)
  File "tmp.py", line 14, in <module>
    func2("bbb")
  File "/tmp/test_warn/app_code.py", line 9, in func2
    get2(val)
  File "/tmp/test_warn/fake_libmc.py", line 18, in get2
    warnings.warn(val)
  File "/tmp/test_warn/fake_libmc.py", line 7, in warn_with_traceback
    traceback.print_stack(file=log)
/tmp/test_warn/fake_libmc.py:18: UserWarning: bbb
  warnings.warn(val)
chenlijun@redis00 /tmp/test_warn $ cat tmp.py
from app_code import func1, func2


print("see each key the first time")
func1("aaa")
func1("bbb")

print("see each key the second time")
func1("aaa")
func1("bbb")

print("see each key the third time, diff source code")
func2("aaa")
func2("bbb")
chenlijun@redis00 /tmp/test_warn $ cat app_code.py
from fake_libmc import get1, get2


def func1(val):
    get1(val)


def func2(val):
    get2(val)
chenlijun@redis00 /tmp/test_warn $ cat fake_libmc.py
import traceback
import warnings
import sys

def warn_with_traceback(message, category, filename, lineno, file=None, line=None):
    log = file or sys.stderr
    traceback.print_stack(file=log)
    log.write(warnings.formatwarning(message, category, filename, lineno, line))

warnings.showwarning = warn_with_traceback


def get1(val):
    warnings.warn(val)


def get2(val):
    warnings.warn(val)