How can I disable spring cloud stream for development purpose when there are not kafka broker running?

Question

I have multiples spring boot apps implementing spring cloud stream with kafka brokers. I'd like to know if I can stop or disable spring cloud stream or kafka broker connections to enable apps to start.

Answer 1

Apps should start even the brokers are not available.

You could add a noop Binder in the classpath and make it a default binder or specify it for your binding. Here some code with Kotlin:

The NoOpBinder implementation class:

package com.demo

import org.slf4j.LoggerFactory
import org.springframework.cloud.stream.binder.Binder
import org.springframework.cloud.stream.binder.Binding
import org.springframework.cloud.stream.binder.ConsumerProperties
import org.springframework.cloud.stream.binder.ProducerProperties
import org.springframework.messaging.MessageChannel

class NoOpBinder : Binder<MessageChannel, ConsumerProperties, ProducerProperties> {
    val logger = LoggerFactory.getLogger(javaClass)!!
    override fun bindConsumer(
        name: String,
        group: String,
        inboundBindTarget: MessageChannel,
        consumerProperties: ConsumerProperties
    ): Binding<MessageChannel> = NoOpBinding(name).also { logger.info("bindConsumer: $it") }

    override fun bindProducer(
        name: String,
        outboundBindTarget: MessageChannel,
        producerProperties: ProducerProperties
    ): Binding<MessageChannel> = NoOpBinding(name).also { logger.info("bindProducer: $it") }

    private class NoOpBinding(val binderName: String) : Binding<MessageChannel> {
        val logger = LoggerFactory.getLogger(javaClass)!!

        override fun getName() = binderName
        override fun unbind() {
            logger.info("unbind: $this")
        }

        override fun toString() = "NoOpBinding [$name]"
    }
}

A configuration class:

package com.demo

import org.springframework.context.annotation.Bean

// Warn: this class is referenced in META-INF/spring.binders and used by spring cloud stream to instantiate binders.
class NoOpBinderServiceConfigurer {

    @Bean
    fun noOpBinder() = NoOpBinder()

}

// resources/META-INF/spring.binders

noop: com.demo.NoOpBinderServiceConfigurer

Specify the binder in your configuration file application.yml

spring:
  cloud:
    stream:
      bindings:
        my-binding:
          destination: my-destination
          group: my-group
          binder: noop

Or specify the default binder in your configuration file application.yml

spring:
  cloud:
    stream:
      bindings:
        defaultBinder: noop

--

Reference:

• https://cloud.spring.io/spring-cloud-stream/spring-cloud-stream.html#multiple-binders

Answer 2

You can do this by disabling the kafka binding in the spring boot application

1. Application class

   import org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration;
   
   @SpringBootApplication(exclude = KafkaAutoConfiguration.class)
   
   public class Application {
     ...
   }
   

2. application.yml (If using yml)

   spring: 
     autoconfigure:
       exclude: org.org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration
   

3. application.properties (If using properties)

   spring.autoconfigure.exclude=org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration