Multi-Binder Configuration

Spring Cloud Stream supports configuring multiple named binders in a single application. The AMPS binder fully supports this, allowing you to connect to multiple AMPS server clusters or combine AMPS with other messaging systems (e.g., Kafka).

Default Binder

When using multiple binders, you should specify a default binder. All bindings without an explicit binder property will use the default:

spring:
  cloud:
    stream:
      default-binder: amps1

Defining Multiple AMPS Binders

Declare named binders under spring.cloud.stream.binders:

spring:
  cloud:
    stream:
      binders:
        amps-primary:
          type: amps
          environment:
            spring.cloud.stream.amps.binder:
              name: primary
              brokers:
                - tcp://amps-primary-1:50000/json
                - tcp://amps-primary-2:50000/json
              publishAmpsHeader: true

        amps-secondary:
          type: amps
          environment:
            spring.cloud.stream.amps.binder:
              name: secondary
              brokers:
                - tcp://amps-secondary:50000/json

Assigning Bindings to Binders

Map each binding to a specific binder:

spring:
  cloud:
    stream:
      bindings:
        orders-in-0:
          destination: orders
          binder: amps-primary
        analytics-out-0:
          destination: analytics
          binder: amps-secondary

Per-Binder Consumer/Producer Properties

AMPS-specific properties for bindings are scoped under each binder's environment:

spring:
  cloud:
    stream:
      binders:
        amps-primary:
          type: amps
          environment:
            spring.cloud.stream.amps:
              binder:
                brokers:
                  - tcp://amps-primary:50000/json
              bindings:
                orders-in-0:
                  consumer:
                    sow: true
                    filter: "/status = 'ACTIVE'"

Mixing AMPS with Other Binders

You can combine AMPS with Kafka, RabbitMQ, or any other Spring Cloud Stream binder. Each binder must have a type (e.g., amps, kafka, rabbit). Set a default-binder and assign specific bindings to specific binders:

spring:
  cloud:
    stream:
      default-binder: amps1
      binders:
        amps1:
          type: amps
          environment:
            spring.cloud.stream.amps.binder:
              name: amps1
              brokers: amps-host-1:50000
        amps2:
          type: amps
          environment:
            spring.cloud.stream.amps.binder:
              name: amps2
              brokers: amps-host-2:50000
        kafka1:
          type: kafka
          environment:
            spring.cloud.stream.kafka.binder:
              brokers: kafka-host:9092
      bindings:
        output1:
          destination: /topic1
          binder: amps1
        input1:
          destination: /topic1/queue
          binder: amps2
        output2:
          destination: topic2
          binder: kafka1

Bean Resolution in Multi-Binder

Spring Cloud Stream's DefaultBinderFactory creates child application contexts for each named binder. The AMPS binder handles this by searching for beans with both the original name and a _child suffix.

If you define custom beans (e.g., BookmarkStoreProvider, Authenticator) at the application level, they are automatically discovered by child binder contexts.

Complete Multi-Binder Example

spring:
  cloud:
    stream:
      binders:
        amps1:
          type: amps
          environment:
            spring.cloud.stream.amps:
              binder:
                name: trading-app
                brokers:
                  - tcp://amps-east-1:50000/json
                  - tcp://amps-east-2:50000/json
                publishAmpsHeader: true
                authenticatorBeanName: kerbAuth
              bindings:
                orders-in-0:
                  consumer:
                    sow: true
                    bookmarkType: MOST_RECENT

        amps2:
          type: amps
          environment:
            spring.cloud.stream.amps:
              binder:
                name: analytics-app
                brokers:
                  - tcp://amps-west-1:50000/json
              bindings:
                metrics-out-0:
                  producer:
                    ackType: Persisted

      bindings:
        orders-in-0:
          destination: orders
          binder: amps1
        metrics-out-0:
          destination: metrics
          binder: amps2

      function:
        definition: processOrders