faulthandler
— 转储 Python 回溯
¶
Added in version 3.3.
faulthandler
— 转储 Python 回溯
¶
Added in version 3.3.
This module contains functions to dump Python tracebacks explicitly, on a fault, after a timeout, or on a user signal. Call
faulthandler.enable()
to install fault handlers for the
SIGSEGV
,
SIGFPE
,
SIGABRT
,
SIGBUS
，和
SIGILL
signals. You can also enable them at startup by setting the
PYTHONFAULTHANDLER
environment variable or by using the
-X
faulthandler
命令行选项。
The fault handler is compatible with system fault handlers like Apport or the Windows fault handler. The module uses an alternative stack for signal handlers if the
sigaltstack()
function is available. This allows it to dump the traceback even on a stack overflow.
The fault handler is called on catastrophic cases and therefore can only use signal-safe functions (e.g. it cannot allocate memory on the heap). Because of this limitation traceback dumping is minimal compared to normal Python tracebacks:
仅支持 ASCII。
backslashreplace
error handler is used on encoding.
Each string is limited to 500 characters.
Only the filename, the function name and the line number are displayed. (no source code)
It is limited to 100 frames and 100 threads.
The order is reversed: the most recent call is shown first.
By default, the Python traceback is written to
sys.stderr
. To see tracebacks, applications must be run in the terminal. A log file can alternatively be passed to
faulthandler.enable()
.
The module is implemented in C, so tracebacks can be dumped on a crash or when Python is deadlocked.
The
Python 开发模式
调用
faulthandler.enable()
在 Python 启动时。
另请参阅
Dump the tracebacks of all threads into
file
。若
all_threads
is
False
, dump only the current thread.
另请参阅
traceback.print_tb()
, which can be used to print a traceback object.
3.5 版改变： Added support for passing file descriptor to this function.
Enable the fault handler: install handlers for the
SIGSEGV
,
SIGFPE
,
SIGABRT
,
SIGBUS
and
SIGILL
signals to dump the Python traceback. If
all_threads
is
True
, produce tracebacks for every running thread. Otherwise, dump only the current thread.
The file must be kept open until the fault handler is disabled: see issue with file descriptors .
3.5 版改变： Added support for passing file descriptor to this function.
3.6 版改变： On Windows, a handler for Windows exception is also installed.
3.10 版改变： The dump now mentions if a garbage collector collection is running if all_threads 为 True。
Disable the fault handler: uninstall the signal handlers installed by
enable()
.
Check if the fault handler is enabled.
Dump the tracebacks of all threads, after a timeout of
timeout
seconds, or every
timeout
seconds if
repeat
is
True
。若
exit
is
True
，调用
_exit()
with status=1 after dumping the tracebacks. (Note
_exit()
exits the process immediately, which means it doesn’t do any cleanup like flushing file buffers.) If the function is called twice, the new call replaces previous parameters and resets the timeout. The timer has a sub-second resolution.
The
file
must be kept open until the traceback is dumped or
cancel_dump_traceback_later()
is called: see
issue with file descriptors
.
This function is implemented using a watchdog thread.
3.5 版改变： Added support for passing file descriptor to this function.
3.7 版改变： This function is now always available.
Cancel the last call to
dump_traceback_later()
.
Register a user signal: install a handler for the
signum
signal to dump the traceback of all threads, or of the current thread if
all_threads
is
False
，进
file
. Call the previous handler if chain is
True
.
The
file
must be kept open until the signal is unregistered by
unregister()
: see
issue with file descriptors
.
不可用于 Windows。
3.5 版改变： Added support for passing file descriptor to this function.
Unregister a user signal: uninstall the handler of the
signum
signal installed by
register()
。返回
True
if the signal was registered,
False
否则。
不可用于 Windows。
enable()
,
dump_traceback_later()
and
register()
keep the file descriptor of their
file
argument. If the file is closed and its file descriptor is reused by a new file, or if
os.dup2()
is used to replace the file descriptor, the traceback will be written into a different file. Call these functions again each time that the file is replaced.
Example of a segmentation fault on Linux with and without enabling the fault handler:
$ python -c "import ctypes; ctypes.string_at(0)"
Segmentation fault
$ python -q -X faulthandler
>>> import ctypes
>>> ctypes.string_at(0)
Fatal Python error: Segmentation fault
Current thread 0x00007fb899f39700 (most recent call first):
File "/home/python/cpython/Lib/ctypes/__init__.py", line 486 in string_at
File "<stdin>", line 1 in <module>
Segmentation fault