Spring Boot + Kafka handle if Kafka is not available - spring

Question

I'm trying to push some non-critical data into Kafka, but I'd still like the application to run without Kafka. However my Spring Boot (with spring-kafka 2.7.2) now won't start normall and it's in a loop of:
[AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available.
Basically this blocks all http requests to my app because I guess the startup process cannot be completed until it connects to Kafka. After maybe a minute, I get the "Tomcat started xx" message, so now the application runs, I guess?
Except when now anything calls a Kafka related services, it again goes into a loop of:
org.apache.kafka.clients.NetworkClient : [Producer clientId=producer-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available.
[ad | producer-1] org.apache.kafka.clients.NetworkClient : [Producer clientId=producer-1] Bootstrap broker localhost:9092 (id: -1 rack: null) disconnected
This again goes for 60 seconds, then it stops, and I get internal server error.
I'd like to simply treat Kafka as an optional service even though on production we will have it up constantly, this might not be true for any of the testing or development servers or developer machines etc. Basically "if it is running, push this data to this topic, if its not running, fine" situation.
Is there a way to config Spring with Kafka so it does not block everything like this (and ideally this all should run in a background thread, which is another thing, but very weird that Kafka would block all the main thread of a request)?
Thanks

Answer 1

I have experienced the same in one of the projects so I did enabled/disabled the Kafka service class through conditionalOnExpression like below.
#Service
#ConditionalOnExpression(value = "'${kafka.enabled}'.equalsIgnoreCase('true')")
public class kafkaPosting {
....
}
Please note to add the property (kafka.enabled) in your application.properties file.
Moreover, if you are Autowiring Kafka bean into your service class then don't forget to add the below to the injection.
#Autowired(required=false)
KafkaClient kafkaClient;
This will help to bypass the kafka based on the configured properties.