Remote Events migrated from Spring Bus to Spring Cloud Stream (#2563)

* Remote Events migrated from Spring Bus to Spring Cloud Stream

---------

Co-authored-by: vasilchev <vasil.ilchev@bosch.com>

hawkbit-mgmt/hawkbit-mgmt-resource/src/test/java/org/eclipse/hawkbit/mgmt/rest/resource/MgmtTargetTagResourceTest.java

@@ -256,7 +256,7 @@ public class MgmtTargetTagResourceTest extends AbstractManagementApiIntegrationT
     @Test
     @ExpectEvents({
             @Expect(type = TargetTagCreatedEvent.class, count = 1),
-            @Expect(type = TargetCreatedEvent.class, count = 5), 
+            @Expect(type = TargetCreatedEvent.class, count = 5),
             @Expect(type = TargetUpdatedEvent.class, count = 5) })
     public void getAssignedTargetsWithPagingLimitRequestParameter() throws Exception {
         final TargetTag tag = testdataFactory.createTargetTags(1, "").get(0);
@@ -280,7 +280,7 @@ public class MgmtTargetTagResourceTest extends AbstractManagementApiIntegrationT
     @Test
     @ExpectEvents({
             @Expect(type = TargetTagCreatedEvent.class, count = 1),
-            @Expect(type = TargetCreatedEvent.class, count = 5), 
+            @Expect(type = TargetCreatedEvent.class, count = 5),
             @Expect(type = TargetUpdatedEvent.class, count = 5) })
     public void getAssignedTargetsWithPagingLimitAndOffsetRequestParameter() throws Exception {
         final TargetTag tag = testdataFactory.createTargetTags(1, "").get(0);

hawkbit-mgmt/hawkbit-mgmt-resource/src/test/resources/mgmt-test.properties

@@ -11,6 +11,4 @@
 # Logging START - activate to see request/response details
 #logging.level.org.eclipse.hawkbit.rest.util.MockMvcResultPrinter=DEBUG
 # Logging END
-
-# disable spring cloud bus for tests
-spring.cloud.bus.enabled=false
+org.eclipse.hawkbit.events.remote-enabled=false

hawkbit-mgmt/hawkbit-mgmt-server/README.md

@@ -24,17 +24,46 @@ run org.eclipse.hawkbit.app.mgmt.MgmtServerStart
 The Management API can be accessed via http://localhost:8080/rest/v1
 The root url http://localhost:8080 will redirect directly to the Swagger Management UI
 
-### Clustering (Experimental!!!)
+# Clustering (Experimental!!!)
+## Events
 
-The micro-service instances are configured to communicate via Spring Cloud Bus. You could run multiple instances of any
-micro-service but hawkbit-mgmt-server. Management server run some schedulers which shall not run simultaneously - e.g.
-auto assignment checker and rollouts executor. To run multiple management server instances you shall do some extensions
-of hawkbit to ensure that they wont run schedulers simultaneously or you shall configure all instances but one to do not
-run schedulers!
+Event communication between nodes is based on  [Spring Cloud Stream](http://docs.spring.io/spring-cloud-stream/docs/current/reference/htmlsingle/).
+There are different [binder implementations](http://docs.spring.io/spring-cloud-stream/docs/current/reference/htmlsingle/#_binders)
+available. The _hawkbit Update Server_ uses RabbitMQ binder.
 
-## Optional Protostuff for Spring cloud bus
+You can run multiple instances of any micro-service, including those consuming events.
+However, the `hawkbit-mgmt-server` should typically be run as a single instance, as it schedules time-sensitive jobs such as auto-assignment checking and rollout execution.
+If multiple management server instances are needed, you must extend hawkBit to ensure that scheduled tasks do not run concurrently.
+Alternatively, configure all but one instance to disable scheduler execution.
 
-The micro-service instances are configured to communicate via Spring Cloud Bus. Optionally, you could
+## Event Channel Types in Spring Cloud Stream
+
+Remote events in hawkBit are distributed through **two distinct types of channels**:
+
+### 1. Fanout Event Channel
+
+- Every service instance listening to `fanoutEventChannel` receives **a copy of every message**, regardless of instance count.
+- Common for events that should be processed by each consumer independently
+  - In-memory cache updates
+  - Internal state propagation
+  - Logging or auditing
+- Not recommended for scenarios where only one consumer should process an event (see `serviceEventChannel` for that).
+
+**Note**: Every instance bound to this channel will get its own copy of the message.
+
+### 2. Service Event Channel
+
+The `serviceEventChannel` is used to **ensure exclusive consumption of events** across service instances.
+Only **one instance per consumer group** receives and processes each message, which is critical for non-idempotent or resource-sensitive operations.
+
+- Only one instance in a consumer group receives each message.
+- Ideal for external integrations, third-party API calls, or any task that must not be duplicated.
+- Load-balanced across instances within the same group.
+
+
+### Optional Protostuff for Spring cloud stream
+
+The micro-service instances are configured to communicate via Spring Cloud Stream. Optionally, you could
 use [Protostuff](https://github.com/protostuff/protostuff) based message payload serialization for improved performance.
 
 **Note**: If Protostuff is enabled it shall be enabled on all microservices!
@@ -42,19 +71,18 @@ use [Protostuff](https://github.com/protostuff/protostuff) based message payload
 Add/Uncomment to/in your `application.properties` :
 
 ```properties
-spring.cloud.stream.bindings.springCloudBusInput.content-type=application/binary+protostuff
-spring.cloud.stream.bindings.springCloudBusOutput.content-type=application/binary+protostuff
+spring.cloud.stream.default.content-type=application/binary+protostuff
 ```
 
 Add to your `pom.xml` :
 
 ```xml
 <dependency>
-  <groupId>io.protostuff</groupId>
-  <artifactId>protostuff-core</artifactId>
+    <groupId>io.protostuff</groupId>
+    <artifactId>protostuff-core</artifactId>
 </dependency>
 <dependency>
-  <groupId>io.protostuff</groupId>
-  <artifactId>protostuff-runtime</artifactId>
+    <groupId>io.protostuff</groupId>
+    <artifactId>protostuff-runtime</artifactId>
 </dependency>
 ```

hawkbit-mgmt/hawkbit-mgmt-server/src/main/resources/application.properties

@@ -14,7 +14,6 @@ spring.main.allow-bean-definition-overriding=true
 spring.port=8080
 
 # Logging configuration
-logging.level.org.eclipse.hawkbit.eventbus.DeadEventListener=WARN
 logging.level.org.springframework.boot.actuate.audit.listener.AuditListener=WARN
 logging.level.org.hibernate.validator.internal.util.Version=WARN
 # security Log with hints on potential attacks
@@ -43,15 +42,6 @@ hawkbit.server.repository.publish-target-poll-event=false
 
 # Disable discovery client of spring-cloud-commons
 spring.cloud.discovery.enabled=false
-# Configure communication between services
-endpoints.spring.cloud.bus.refresh.enabled=false
-endpoints.spring.cloud.bus.env.enabled=false
-spring.cloud.stream.bindings.springCloudBusInput.group=mgmt-server
-
-# To use protostuff (for instance fot improved performance) you shall uncomment
-# the following two lines and add io.protostuff:protostuff-core and io.protostuff:protostuff-runtime to dependencies
-#spring.cloud.stream.bindings.springCloudBusInput.content-type=application/binary+protostuff
-#spring.cloud.stream.bindings.springCloudBusOutput.content-type=application/binary+protostuff
 
 # Swagger Configuration / https://springdoc.org/v2/#properties
 springdoc.api-docs.version=openapi_3_0
@@ -61,4 +51,9 @@ springdoc.packages-to-scan=org.eclipse.hawkbit.mgmt
 springdoc.paths-to-exclude=/system/**
 springdoc.swagger-ui.enabled=true
 springdoc.swagger-ui.csrf.enabled=true
-springdoc.swagger-ui.doc-expansion=none
+springdoc.swagger-ui.doc-expansion=none
+
+# remote events configuration
+spring.config.import=classpath:/hawkbit-events-defaults.properties
+# Optional: Use protostuff (if enabled)
+# spring.cloud.stream.default.content-type=application/binary+protostuff