Python の traceback で例外発生時の情報を取得する方法のメモ。

プログラム

以下で traceback で取得できる情報を確認する。

traceback.py

import traceback


def func():
    print(f"func(): begin")
    raise "error"
    print(f"func(): end")


def main():
    print(f"main(): start")
    try:
        func()
    except Exception as e:
        print("\ntraceback.format_exception()")
        print(traceback.format_exception(e))

        print("\ntraceback.format_stack()")
        print(traceback.format_stack())

        print("\ntraceback.extract_tb(e.__traceback__)")
        print(traceback.extract_tb(e.__traceback__))

        print("\ne.__traceback__")
        print(e.__traceback__)

    print(f"main(): end")
    return 0


if __name__ == "__main__":
    res = main()
    exit(res)

実行結果

traceback.format_exception()

['Traceback (most recent call last):\n', '  File "/.../traceback.py", line 18, in main\n    func()\n', '  File "/.../traceback.py", line 11, in func\n    raise "error"\n', 'TypeError: exceptions must derive from BaseException\n']

traceback.format_stack()

python:
['  File "/.../traceback.py", line 37, in <module>\n    res = main()\n', '  File "/.../traceback.py", line 24, in main\n    print(traceback.format_stack())\n']

traceback.extract_tb(e.traceback)

['  File "/.../traceback.py", line 37, in <module>\n    res = main()\n', '  File "/.../traceback.py", line 24, in main\n    print(traceback.format_stack())\n']

e.traceback

<traceback object at 0x7fbf1770b740>