Fix issues in KafkaAuthnHandler #849
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Type of change
Description
I set up an SASL authentication with the KafkaAuthnHandler. The ApiVersions and SaslHandshake request work just fine. However, the SaslAuthenticate request is sent but not received by netty. After some debugging, I found that the auto-read config is disabled by the KafkaProxyFrontendHandler.
After authentication, kafka client will send an ApiVersions request again that will transition the state from AUTHN_SUCCESS to API_VERSIONS, which I think is inappropriate.
An OpaqueRequestFrame will also be treated as an unexpected message.
Additional Context
Set up custom SASL mechanisms with the KafkaAuthnHandler.
Checklist