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  1. Stratos
  2. STRATOS-777

Introduce subscription filters to intercept a new subscription


    • Type: New Feature
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 4.0.0
    • Fix Version/s: 4.1.0 RC3
    • Component/s: Stratos Manager
    • Labels:


      Currently, there's no clean way to intercept a subscription request and do some pre-processing. As of now, we do some pre-processing of a subscription request in order to identify the need of a load balancer and act accordingly. I currently have another use-case to intercept a subscription request and act upon a parameter.

      Hence, to make the code clean over there, I propose we introduce a Subscription Filter chain where you could intercept a subscription request and do some pre-processing before creating the actual subscription.

      Following is the interface design, I've come up with.


      • Intercepts the flow of Cartridge Subscription.
      • Implementations of this class would get executed before making the real subscription.
        public interface SubscriptionFilter {


      • Do some pre-processing on a subscription request.
      • @param cartridgeInfo {@link CartridgeInfo}
      • @param subscriptionData {@link SubscriptionData}
      • @return {@link Properties}

        , if there are any.

      • @throws ADCException on a failure while processing.
        public Properties execute(CartridgeInfo cartridgeInfo, SubscriptionData subscriptionData) throws ADCException ;

      Filters could leverage these key-value pairs to pass properties into the main subscription.

      One existing use-case is passing LB subscription related properties to the main subscription.

      You would need to implement the interface and add the fully qualified class name of it, to the META-INF/services folder in a file named "org.apache.stratos.manager.subscription.filter.SubscriptionFilter" (I am planning to use the Java ServiceLoader - http://docs.oracle.com/javase/6/docs/api/java/util/ServiceLoader.html)




            • Assignee:
              nirmal Nirmal Fernando
              nirmal Nirmal Fernando
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