Grails RabbitMQ native: AuthenticationFailureException on interpolated credentials

Using the Grails RabbitMQ-native plugin, when using environment variable interpolation in the configuration of the Rabbit connection in the application.yml, the interpolation doesn't work:

rabbitmq:
    connections:
      - name: defaultConnection
        host: example.com
        username: ${RABBITMQ_USER}
        password: bar

Leads to an AuthenticationFailureException while hardcoding the same credentials work.

Is there a workaround? I don't want to hardcode the credentials to our RabbitMQ instance...

A workaround is to define the rabbitMQ connections in the application.groovy file.

Example:

// Rabbitmq connection configuration
rabbitmq {
    connections = [
            [
                    name: "main",
                    host: System.getenv('RABBITMQ_HOST'),
                    username: System.getenv('RABBITMQ_USER'),
                    password: System.getenv('RABBITMQ_PASS')
            ]
    ]
}