Dynamically set RoutingKey={application} as an option

[gustavo-armenta]

Question or Enhancement

I deployed ConfigServer as a PCF webapp

• A developer commits a configuration change in the git repo
• GitHub detects the change and triggers a hook sending a web request to ConfigServer/monitor
• ConfigServer receives the request, git pull to get latest changes, and writes a message to SpringCloudBus (rabbitmq) to notify clients
• Clients receive the notification and reloads values from ConfigServer

I am using one instance of ConfigServer to handle configuration changes for many applications (multitenant). The message written to SpringCloudBus has RoutingKey=”springCloudBus” and Payload contains “destinationService”:”{application}:**”. My problem is the message is received by clients from all applications and every app has to add code to filter by destinationService. I want the message to be received only by the {application} clients and it can be accomplished by setting RoutingKey={application}. Is there any way to do it today? Is it in the backlog?

[spencergibb]

Every spring bus client already has code to filter by destination service. Why do you need to add code?

[gustavo-armenta]

My application is in dotnet core. Steeltoe does not provide the SpringCloudBus client

[spencergibb]

Ack. :+1:

[spencergibb]

@olegz or @sobychacko I think the question here is: is there a way to dynamically set the RoutingKey using spring cloud stream abstractions?

[olegz]

@spencergibb I think routingKeyExpression producer property is what you're looking for.

A SpEL expression to determine the routing key to use when publishing messages. For a fixed routing key, use a literal expression, such as routingKeyExpression='my.routingKey' in a properties file or routingKeyExpression: '''my.routingKey''' in a YAML file.

https://cloud.spring.io/spring-cloud-stream-binder-rabbit/spring-cloud-stream-binder-rabbit.html#_rabbit_producer_properties

[spencergibb]

Interesting. What object is available as context for the expression? OP wants something dynamic.

[olegz]

It's extended Rabbit producer properties: spring.cloud.stream.rabbit.bindings.<channelName>.producer.routing-key-expression=blah