泄漏到标准错误中的异常

Question

我正在尝试捕获paramiko异常，但它们仍被写入stderr。

有没有办法停止在那儿写作？

编辑：甚至在paramiko参与之前就发生了：

import pysftp

try:
    pysftp.Connection(host="localhost")
except Exception as e:
    print(e)

结果：

具有正确的SFTP参数的示例：

UPDATE：

$ pipenv graph
...
pysftp==0.2.9
  - paramiko [required: >=1.17, installed: 2.6.0]
...

$ pipenv run python
Python 3.7.3 (default, Jul 19 2019, 11:21:39)
[Clang 11.0.0 (clang-1100.0.28.3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pysftp
>>> try:
...     pysftp.Connection(host="localhost")
... except Exception as e:
...     print(e)
...
No hostkey for host localhost found.
Exception ignored in: <function Connection.__del__ at 0x10f7e8268>
Traceback (most recent call last):
  File "/Users/andrei/Work/try/.venv/lib/python3.7/site-packages/pysftp/__init__.py", line 1013, in __del__
    self.close()
  File "/Users/andrei/Work/try/.venv/lib/python3.7/site-packages/pysftp/__init__.py", line 784, in close
    if self._sftp_live:
AttributeError: 'Connection' object has no attribute '_sftp_live'
>>>

Answer 1

我想指出PySFTP（[PyPI]: PySFTP）已有[3 +年未维护（或已移至其他位置-到目前为止保密:)）。

我转载了问题。下面是您的代码的更详细的版本。

code00.py：

#!/usr/bin/env python3

import sys
import pysftp
import traceback


def main(argv):
    hostname = argv[0] if argv else "localhost"
    print("Attempting to connect to {0:s} ...".format(hostname))
    try:
        print("----------Before conn----------")
        conn = pysftp.Connection(host=hostname)
        print("----------After conn----------")
    except:
        print("----------Before exc print----------")
        traceback.print_exc()
        print("----------After exc print----------")
    finally:
        print("----------Finally----------")
    print("----------After try / except / finally----------")

if __name__ == "__main__":
    print("Python {0:s} {1:d}bit on {2:s}".format(" ".join(item.strip() for item in sys.version.split("\n")), 64 if sys.maxsize > 0x100000000 else 32, sys.platform))
    print("pysftp version: {0:s}\n".format(pysftp.__version__))
    main(sys.argv[1:])
    print("\nDone.")

输出：

[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q058110732]> "e:\Work\Dev\VEnvs\py_064_03.07.03_test0\Scripts\python.exe" code00.py
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD64)] 64bit on win32
pysftp version: 0.2.9

Attempting to connect to localhost ...
----------Before conn----------
e:\Work\Dev\VEnvs\py_064_03.07.03_test0\lib\site-packages\pysftp\__init__.py:61: UserWarning: Failed to load HostKeys from C:\Users\cfati\.ssh\known_hosts.  You will need to explicitly load HostKeys (cnopts.hostkeys.load(filename)) or disableHostKey checking (cnopts.hostkeys = None).
  warnings.warn(wmsg, UserWarning)
----------Before exc print----------
Traceback (most recent call last):
  File "code00.py", line 13, in main
    conn = pysftp.Connection(host=hostname)
  File "e:\Work\Dev\VEnvs\py_064_03.07.03_test0\lib\site-packages\pysftp\__init__.py", line 132, in __init__
    self._tconnect['hostkey'] = self._cnopts.get_hostkey(host)
  File "e:\Work\Dev\VEnvs\py_064_03.07.03_test0\lib\site-packages\pysftp\__init__.py", line 71, in get_hostkey
    raise SSHException("No hostkey for host %s found." % host)
paramiko.ssh_exception.SSHException: No hostkey for host localhost found.
----------After exc print----------
Exception ignored in: <function Connection.__del__ at 0x000001CC720C80D0>
Traceback (most recent call last):
  File "e:\Work\Dev\VEnvs\py_064_03.07.03_test0\lib\site-packages\pysftp\__init__.py", line 1013, in __del__
    self.close()
  File "e:\Work\Dev\VEnvs\py_064_03.07.03_test0\lib\site-packages\pysftp\__init__.py", line 784, in close
    if self._sftp_live:
AttributeError: 'Connection' object has no attribute '_sftp_live'
----------Finally----------
----------After try / except / finally----------

Done.

这是PySFTP错误：

1. 在初始化程序中的某个地方发生异常
2. 不执行异常后的行
3. 当对象被（自动）垃圾回收时，在其析构函数中，将引用某些属性
4. 但是由于这些属性初始化发生在＃2。的行的[[after中，所以它们从未被初始化，因此它们的引用引发AttributeError

解决方法很简单：在初始化程序的开头将属性初始化为一些默认值，因此，如果发生上述情况，则对它们的引用不会出现问题。

我注意到您已经在

BitBucket

上提交了问题。考虑：

我不是
• BitBucket

专家我没有[BitBucket]: dundeemt/pysftp - pysftp is an easy to use sftp module that utilizes paramiko and pycrypto.的权限（我既不能推送也不能提交请求请求）

我创建了自己的

repo

（在上一个中），并将更改推送到：[[[BitBucket]: CristiFati0/pysftp - [Issue #144]: Exceptions leaking into stderr（到目前为止，一次提交）。输出（在将修补程序手动应用于

pip

安装的文件之后）：

[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q058110732]> "e:\Work\Dev\VEnvs\py_064_03.07.03_test0\Scripts\python.exe" code00.py
Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD64)] 64bit on win32
pysftp version: 0.2.9

Attempting to connect to localhost ...
----------Before conn----------
e:\Work\Dev\VEnvs\py_064_03.07.03_test0\lib\site-packages\pysftp\__init__.py:61: UserWarning: Failed to load HostKeys from C:\Users\cfati\.ssh\known_hosts.  You will need to explicitly load HostKeys (cnopts.hostkeys.load(filename)) or disableHostKey checking (cnopts.hostkeys = None).
  warnings.warn(wmsg, UserWarning)
----------Before exc print----------
Traceback (most recent call last):
  File "code00.py", line 13, in main
    conn = pysftp.Connection(host=hostname)
  File "e:\Work\Dev\VEnvs\py_064_03.07.03_test0\lib\site-packages\pysftp\__init__.py", line 135, in __init__
    self._tconnect['hostkey'] = self._cnopts.get_hostkey(host)
  File "e:\Work\Dev\VEnvs\py_064_03.07.03_test0\lib\site-packages\pysftp\__init__.py", line 71, in get_hostkey
    raise SSHException("No hostkey for host %s found." % host)
paramiko.ssh_exception.SSHException: No hostkey for host localhost found.
----------After exc print----------
----------Finally----------
----------After try / except / finally----------

Done.

不用说，对于不同的情况，可能会引发其他未处理的异常。