Event Hub and Subscription Validation Model

When using WSO2 API Manager as the key manager with Microgateway, it can be configured to validate the API Subscriptions. For this, the same API should be published in both API Manager and Microgateway, and a valid access token (JWT or Reference token) should be obtained by subscribing to the API via an Application. Microgateway is capable of validating subscriptions only for the configured tenant (One tenant per Microgateway basis).

Subscription Validation Model

Subscriptions are validated in the Microgateway itself using a set of internal data stores. These data stores contain APIs, Applications, and Subscription related information.

The following are the data stores that are being used.

Data Store Description
Application Key Mapping Data Store Holds the consumer key and the corresponding applicatioId of Oauth applications created in API Manager
Application Data Store Stores information about the Applications (id, application throttling policy, etc)
API Data Store Stores API information (API Name, Version, Owner, etc)
Subscription Data Store Stores API Subscription data. (API id, subscribed app id, subscription status, subscription policy)

Subscription Validation Process

  1. Validate the token and get the consumer key (using the aud claim of JWT or introspection response).
  2. Check in the Application Key Mapping Data store and get the Application Id for the consumer key.
  3. If the Application Key Mapping is not found, invoke the internal data API and retrieve the application key mapping information.
  4. If an entry is not found for the consumer key, the subscription validation is considered failed.
  5. Get the API information from the API data store. (API id)
  6. Get subscription information for API id and application id from the subscription data store.
  7. If the subscription data is not found, invoke the internal data api and fetch any subscription data available.
  8. If subscription data is not found (in data stores and api manager) then, the subscription is considered failed.
  9. If a valid subscription is found, then the relevant data is populated into the internal context for other functions (analytics data, throttling, etc)

The Event Hub

Event Hub is the endpoint configuration which is used to fetch API, Application and Subscription data from WSO2 API Manager.

Microgateway uses the below methods to fetch API and subscription-related data from API Manager.

  • Internal Data REST API
  • JMS Topic

The Internal Data API (https://<APIM_HOST>:<PORT>/internal/data/v1) is a REST API exposed in WSO2 API Manager to retrieve data related to APIs, Applications, subscriptions, etc. During the startup, Microgateway invokes this API to fetch the already published API and subscription data of the configured tenant.

For new API Creations and Subscription creations, API Manager publishes an event through a JMS topic. Microgateways, which are subscribed to the topic, update the in-memory data stores when the event is received.

Event Hub Configuration

  enable = true
  service_url = "https://localhost:9443"
  eventListeningEndpoints = "amqp://admin:admin@carbon/carbon?brokerlist='tcp://localhost:5672'"


This feature is available from API Manager 3.2.0. If you are using an older version of API Manager, please follow the Configuration for WSO2 API Manager to configure Microgateway correctly.