Re: Custom Kafka Connect REST Extension for Token Authentication

Hi All, 

Has anyone managed to get a REST extension working with multiple connect instances / workers?
Many Thanks, 
Jamie
On Wednesday 16 April 2025 at 10:57:01 BST, Jamie <jamiedd13@aol.co.uk> wrote:

Hi All, 
I'm trying to implement a custom REST extension for Kafka Connect that allows a token to be used for authentication. 
When I have a single instance of Kafka connect running in distributed mode (i.e. 1 worker) this works as expected. However, when I add another instance (another worker) I get an error when the worker that received the request has to forward it on to the group leader:
Error IO error forwarding REST request: (org.apache.kafka.connect.runtime.rest.RestClient:143)
java.util.concurrent.ExecutionException: org.eclipse.jetty.client.HttpResponseException: HTTP protocol violation: Authentication challenge without WWW-Authenticate header 

I noticed that someone also had the same issue with the basic authentication extension that comes as part of connect: https://stackoverflow.com/questions/60977591/kafkaconnect-rest-api-basic-authentication-issue.
Has anyone been able to get either the basic authentication or another custom authentication extension working with Kafka connect when using more than one instance / worker? 

I'm using version 2.7.1 of Kafka and Kafka connect. 

Many Thanks, 

Jamie.