using CallCredentials from Python

[smb...@gmail.com]

Hi, I'm trying to attach CallCredentials to an RPC. This is what I've done, using AccessTokenCallCredentials as an example:

class UsernamePasswordCallCredentials(grpc.AuthMetadataPlugin):

 def __init__(self, username):

       self._username = username

 def __call__(self, context, callback):

       print "in __call__"

       metadata = (('x-custom-auth-ticket', self._username),)

       callback(metadata, None)

       

call_creds = metadata_call_credentials(UsernamePasswordCallCredentials("foo"))

channel = grpc.insecure_channel("localhost:50055")

stub = my_pb2_grpc.myStub(channel)

        stub.ListUser(Empty(), credentials=call_creds)

Not only does my custom header not appear to be set, but I can't find an evidence that UsernamePasswordCallCredentials.__call__ is ever being called. Where am I going wrong?

Thanks,
Scott

[Ken Payson]

Call credentials can only be used on a secure channel.

In your example, it should look something like:

call_creds = grpc.metadata_call_credentials(UsernamePasswordCallCredentials("foo"))

ssl_creds = grpc.ssl_channel_credentials()

channel_creds = grpc.composite_channel_credentials(ssl_creds, call_creds)

channel = grpc.secure_channel("localhost:50055", channel_creds)

Note that your server will need to host a secure port on localhost:50055

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[JI Ioannidis]

Are SSL credentials supported by the python client yet? IOW, if my client does 

  creds = grpc.ssl_channel_credentials(
    root_certificates=ca.crt, 
    private_key=client.key,
    certificate_chain=client.crt)

how can the server access the client cert? I already have mechanisms in place for issuing client certs, it's a bit annoying to have a parallel mechanism for issuing and validating, not to mention worrying about a proper implementation thereof, channel credentials.

I've had this issue for a long time and I still don't have a satisfactory workaround.

tx

/ji

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[Nathaniel Manista]

On Thu, Jan 19, 2017 at 12:34 PM, JI Ioannidis <jay...@gmail.com> wrote:

Are SSL credentials supported by the python client yet?

Well, you can provide them (as you've done in the code below, right?).

IOW, if my client does 

  creds = grpc.ssl_channel_credentials(
    root_certificates=ca.crt, 
    private_key=client.key,
    certificate_chain=client.crt)

how can the server access the client cert?

I don't know that this will be possible prior to the resolution of issue 7710, which isn't on our list of things to fix soon. Can you tell us more about how onerous the feature's absence is to you and how valuable you would find its implementation?

-Nathaniel