我如何让python函数返回异常回溯或结果？(How do I have a python function return an exception traceback, or the result?)

 让我们说我有一个功能： 
 
def ReadFile():
    with open("/etc/passwd") as file:
        data = file.read()
 
 这个函数可能会成功，在这种情况下它需要返回一个结果，否则它可能会失败，在这种情况下我想返回一个异常的回溯，它将通过电子邮件发送给我，所以我知道我的程序中有一些失败，并且确切地说什么失败了。 
 
 要做到这一点，我可以这样做： 
 
import traceback

def ReadFile():
    try:
        with open("/etc/passwd") as file:
            data = file.read()
    except IOError:
        return traceback.format_exc()
    return data
 
 如果能够成功读取文件，则返回文件的内容。 否则，它返回异常的回溯。 
 
 traceback.format_exc（）返回一个字符串。 如果ReadFile（）应该返回一个列表，或者如果成功则返回元组或整数，那么事情很容易 - 当你调用ReadFile（）时，如果返回的结果是一个字符串，你知道它失败了你可以运行代码发送电子邮件你错了，如果结果是你期望的类型（int，tuple，list或w / e），那么你知道它有效。 
 
 如果ReadFile（）应该返回一个字符串，就像在我的例子中那样，而不是确定ReadFile（）是成功还是失败变得非常困难，因为你需要解析字符串以确定它是否看起来像一个回溯或你期望的结果。 
 
 有一个更好的方法吗？ 也许某些方法让traceback返回某种类型的对象，其中包含与traceback.format_exc（）包含的信息相同的信息，这样就可以更容易地判断ReadFile（）是成功还是失败？ 

Lets say I have a function:
 
def ReadFile():
    with open("/etc/passwd") as file:
        data = file.read()
 
This function might succeed, in which case it needs to return a result, or it might fail, in which case I want to return a traceback of the exception, which will get emailed to me so I know something failed in my program, and exactly what failed.
 
To do this, I can do something like:
 
import traceback

def ReadFile():
    try:
        with open("/etc/passwd") as file:
            data = file.read()
    except IOError:
        return traceback.format_exc()
    return data
 
If it is able to read the file successfully, it returns the contents of the file. Otherwise, it returns the traceback of the exception.
 
traceback.format_exc() returns a string. If ReadFile() is supposed to return a list, or tuple or integer if it succeeds, than things are easy - when you call ReadFile(), if the result returned is a string, you know it failed and you can run code that emails you the error, and if the result is the type you expected (int, tuple, list or w/e), than you know it worked.
 
If ReadFile() is supposed to return a string, as it does in my example, than figuring out if ReadFile() succeeded or failed becomes significantly more difficult, as you need to parse the string to figure out if it looks like a traceback or the result you expected.
 
Is there a better way to do this? Perhaps some way to have traceback return some sort of object with the same information as traceback.format_exc() contains, so that it's easier to figure out if ReadFile() succeeded or failed?

原文：https://stackoverflow.com/questions/35953283