CAP Java: Config for Event Messaging with Message Queuing

[simondold67]

Hello,

I'm currently learning CAP Java and trying to implement an event messaging service using the Message Queue Message Broker.

Before I can use the broker I have to configure it in my application.yaml file. (as described in the cap documentation)

I did this as follows:

spring:
config.activate.on-profile: default
cds:
messaging.services:
- name: "messaging"
kind: "message-queuing"

Whenever I try to start the application I get the following error:

***************************
APPLICATION FAILED TO START
***************************

Description:

Field messagingService in customer.message_que_send.handlers.CatalogServiceHandler required a bean of type 'com.sap.cds.services.messaging.MessagingService' that could not be found.

The injection point has the following annotations:
        - @org.springframework.beans.factory.annotation.Autowired(required=true)


Action:

Consider defining a bean of type 'com.sap.cds.services.messaging.MessagingService' in your configuration.<br>

What am I doing wrong in my config?

Or is there another problem?

Thanks for your help.

[dietrich_mostowoj · Accepted solution]

Hello Simon,

you can check the startup log of your application whether the 'messaging' service was registered and initialised properly? Did you install the MQ dependencies in your application pom:

<dependency>
  <groupId>com.sap.cds</groupId>
  <artifactId>cds-feature-message-queuing</artifactId>
  <scope>runtime</scope>
</dependency>

and be carefully with the indentations in the application.yaml:

spring:
  config.activate.on-profile: default
cds:
  messaging.services:
    - name: "messaging"
      kind: "message-queuing"

Regards,

Dietrich

[simondold67 · Accepted solution]

Thanks for your answer!

I correctly indented the config in my application.yaml and have set the dependencies for MQ in my pom.xml.

Unfortunately I still get the error message.

Where can I see if the messaging service has been registered correctly?

I tried event messaging with file-based-messaging, this worked but with MQ I always get the error message as described above.

[dietrich_mostowoj · Accepted solution]

In the startup log of the application you can find all services registrations.

[simondold67 · Accepted solution]

You are right, my log says: "No service bindings with label 'message-queuing' found" what can I do to register the service correctly?

[simondold67 · Accepted solution]

For anyone who has the same problem.

My solution was to bind the cloud service to my application. This is described in this article (Hybrid Testing): https://cap.cloud.sap/docs/advanced/hybrid-testing

First the service needs to be bound with:

cds bind -2 my-hana:my-hana-key.

After that, the application must be started as follows:

cds bind --exec mvn spring-boot:run

[dietrich_mostowoj · Accepted solution]

You need to bind the MQ service to your application, otherwise there is no messaging infrastructure.

[MohanrajV]

can u give demo for java cap messaging please