python - 回溯仅显示多行命令的一行

Question

我在我的服务器上添加了一个小的调试辅助工具。它记录从 traceback.format_stack()

获得的堆栈跟踪

它包含一些像这样的不完整行:

File "/home/...../base/loop.py", line 361, in run
    self.outputs.fd_list, (), sleep)

这不是很有帮助。

源代码行 360 和 361:

rlist, wlist, unused = select.select(self.inputs.fd_list,
                                     self.outputs.fd_list, (), sleep)

如果只有一行可以作为堆栈跟踪的一部分，我会说带有函数名称(这里是 select.select)的第 360 行是正确的，因为堆栈是通过调用创建的功能。

无论如何，我希望打印整行(逻辑)。或者至少是一些上下文(例如之前的 2 行)。那可能吗？当然，我的意思是只要付出足够的努力。

尝试添加续行字符 \，但没有成功。

---

结语:根据 Jean-François Fabre 的回答和他的代码，我将使用这个函数:

def print_trace():
    for fname, lnum, func, line in traceback.extract_stack()[:-1]:
        print('File "{}", line {}, in {}'.format(fname, lnum, func))
        try:
            with open(fname) as f:
                rl = f.readlines()
        except OSError:
            if line is not None:
                print("    " + line + "  <===")
            continue
        first = max(0, lnum-3)
        # read 2 lines before and 2 lines after
        for i, line in enumerate(rl[first:lnum+2]):
            line = line.rstrip()
            if i + first + 1 == lnum:
                print("    " + line + "  <===")
            elif line:
                print("    " + line)

Answer 1

“只要付出足够的努力”这是可以做到的。但它很像黑客

检查这个例子:

import traceback,re,os,sys

r = re.compile(r'File\s"(.*)",\sline\s(\d+)')

def print_trace():
    # discard the 2 deepest entries since they're a call to print_trace()
    lines = [str.split(x,"\n")[0] for x in traceback.format_stack()][:-2]

    for l in lines:
        m = r.search(l)
        if m != None:
            sys.stdout.write(l+"\n")
            file = m.group(1)
            line = int(m.group(2))-1
            if os.path.exists(file):
                with open(file,"r") as f:
                    rl = f.readlines()
                    tblines = rl[max(line-2,0):min(line+3,len(rl))]
                    # read 2 lines before and 2 lines after
                    for i,tl in enumerate(tblines):
                        tl = tl.rstrip()

                        if i==2:
                            sys.stdout.write("    "+tl+" <====\n")
                        elif tl:
                            sys.stdout.write("    "+tl+"\n")


def foo():
    print_trace()

foo()

输出:

  File "C:\Users\dartypc\AppData\Roaming\PyScripter\remserver.py", line 63, in <module>
    if __name__ == "__main__":
        main() <====
  File "C:\Users\dartypc\AppData\Roaming\PyScripter\remserver.py", line 60, in main
        t = SimpleServer(ModSlaveService, port = port, auto_register = False)
        t.start() <====
    if __name__ == "__main__":
  File "C:\Program Files\PyScripter\Lib\rpyc.zip\rpyc\utils\server.py", line 227, in start
  File "C:\Program Files\PyScripter\Lib\rpyc.zip\rpyc\utils\server.py", line 139, in accept
  File "C:\Users\dartypc\AppData\Roaming\PyScripter\remserver.py", line 14, in _accept_method
    class SimpleServer(Server):
        def _accept_method(self, sock):
            self._serve_client(sock, None) <====
    class ModSlaveService(SlaveService):
  File "C:\Program Files\PyScripter\Lib\rpyc.zip\rpyc\utils\server.py", line 191, in _serve_client
  File "C:\Program Files\PyScripter\Lib\rpyc.zip\rpyc\core\protocol.py", line 391, in serve_all
  File "C:\Program Files\PyScripter\Lib\rpyc.zip\rpyc\core\protocol.py", line 382, in serve
  File "C:\Program Files\PyScripter\Lib\rpyc.zip\rpyc\core\protocol.py", line 350, in _dispatch
  File "C:\Program Files\PyScripter\Lib\rpyc.zip\rpyc\core\protocol.py", line 298, in _dispatch_request
  File "C:\Program Files\PyScripter\Lib\rpyc.zip\rpyc\core\protocol.py", line 528, in _handle_call
  File "<string>", line 420, in run_nodebug
  File "C:\DATA\jff\data\python\stackoverflow\traceback_test.py", line 31, in <module>
        print_trace()
    foo() <====

编辑:VPfB 建议使用 extract_stack，它不那么“hacky”，不需要解析字符串，只需获取带有回溯信息的四元组(需要重建文本消息，但是这样更好)

import traceback,os,sys


def print_trace():
    # discard the 2 deepest entries since they're a call to print_trace()

    for file,line,w1,w2 in traceback.extract_stack()[:-2]:
        sys.stdout.write('  File "{}", line {}, in {}\n'.format(file,line,w1))

        if os.path.exists(file):
            line -= 1
            with open(file,"r") as f:
                rl = f.readlines()
                tblines = rl[max(line-2,0):min(line+3,len(rl))]
                # read 2 lines before and 2 lines after
                for i,tl in enumerate(tblines):
                    tl = tl.rstrip()

                    if i==2:
                        sys.stdout.write("    "+tl+" <====\n")
                    elif tl:
                        sys.stdout.write("    "+tl+"\n")


def foo():
    print_trace()

foo()