SSHTunnelForwarder - "IP is not a string (NoneType)"

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I am attempting to use SSHTunnelForwarder. I receive an error "IP is not a string (NoneType)". If I understand correctly, that means the host variable I'm passing is of type NoneType and needs to be String type. Printing out the variables type shows that it is of type string: <class 'str'>.

I've generalized the code in question. See below:

def connectToClient(client):
    key, host = getClientInfo(client)
    # Both of the below print statements return <class 'str'>
    print(type(key))
    print(type(host))

    try:
        with SSHTunnelForwarder(
            ssh_username = "username",
            ssh_private_key = key,
            remote_bind_address = (host, 22)) as server:
                # Do stuff here

    except Exception as e:
        # Handle exception

Stack Trace (edited to hide file system info and .py file name. Also testing with 0.0.0.0):

Traceback (most recent call last):
  File "/path/to/file/myPythonFile.py", line 83, in connectToClient
    remote_bind_address = ('0.0.0.0', 22)) as server:
  File "/path/to/file/lib/python3.6/site-packages/sshtunnel.py", line 908, in __init__
    check_host(self.ssh_host)
  File "/path/to/file/lib/python3.6/site-packages/sshtunnel.py", line 79, in check_host
    type(host).__name__
AssertionError: IP is not a string (NoneType)

I'd like to point out that even if I replace the host variable with a string holding an IP (i.e. '127.0.0.1'), I still receive the same error.

Perhaps I'm making a simple mistake. Any ideas?

Edit: Fix formatting and add stack trace

ssh-tunnel ssh python-3.x python
1 Answers

You are missing an argument. See the example.
In practice, you are calling SSHTunnelForwarder without the keyword argument ssh_address_or_host which represents the IP and optionally the port number of the remote host.
Indeed, you are confusing the meaning of remote_bind_address using it as it is the ssh_address_or_host.

When the method will check for the host part relative to the IP will not find a string, but None and here comes the exception. See the code.

user_13590580
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