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pythonsshparamiko

Paramiko "TypeError: 'NoneType' object is not callable" at the end of a script that execute command on the server

I'm writing a script to execute commands in an EC2 instance, and come back. For that, I'm using Paramiko. My script is like this:

ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect('<hostname>', username='<username>', password='<password>')
print('connected')
stdin, stdout, stderr = ssh.exec_command("ls -lah")
ssh.close()
print('done')

The trace I'm getting is:

connected
done
Exception ignored in: <function BufferedFile.__del__ at 0x7fa5de814950>
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/paramiko/file.py", line 66, in __del__
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/paramiko/channel.py", line 1392, in close
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/paramiko/channel.py", line 991, in shutdown_write
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/paramiko/channel.py", line 963, in shutdown
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/paramiko/channel.py", line 1246, in _send_eof
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/paramiko/message.py", line 232, in add_int
TypeError: 'NoneType' object is not callable

The command which I use to login is:

ssh -o PubkeyAuthentication=no -l <username> <hostname>

Can someone tell me what I'm doing wrong here?

Solution

  • You are not waiting for the command to complete before you close the SSH connection.

    When Python garbage-collects the stdin, stdout and stderr, Paramiko crashes, as it does not expect the connection to be closed.

    For a correct code, see Wait to finish command executed with Python Paramiko.