kafka_franz: No connection errors if `consumer_group: ""`

[kfollesdal]

No connection error when consumer_group: "" If you take the following benthos config and run as it is without any changes. benthos will run without any errors

input:
  kafka_franz:
    seed_brokers:
      - mybroker
    topics:
      - mytopic
    consumer_group: ""
    sasl:
      - mechanism: SCRAM-SHA-256
        username: <USERNAME>
        password: <PASSOWRD>

I would expect this to faile. But benthos runs quietly without any error.

INFO Running main config from file found in a default path  @service=benthos benthos_version=24.1.7 path=connect.yaml
INFO Launching a Redpanda Connect instance, use CTRL+C to close  @service=benthos
INFO Output type stdout is now active              @service=benthos label="" path=root.output
INFO Listening for HTTP requests at: http://0.0.0.0:4195  @service=benthos
INFO Input type kafka_franz is now active          @service=benthos label="" path=root.input

But if you set consumer_group to something other than "" you get expected error, that broker do not exist:

WARN unable to open connection to broker           @service=benthos addr="mybroker:9092" broker=seed_0 err="dial tcp: lookup mybroker on 8.8.8.8:53: no such host" label="" path=root.input

or SASL authentication failed: security: Invalid credentials... if you use and valid broker but wrong username/password. You do not get any of these errors with consumer_group set to ""

Version: rpk version v24.1.7 (rev 53e6eab6ab)