JSON schema validation at Datapower

Question

As per our current architecture, we have Datapower that acts as a gatekeeper for validating each incoming request (in JSON) against JSON schemas.

We have lot of restful services having corresponding JSON schemas residing at Datapower itself. However, every time there is a change in service definition corresponding schema has to be changed. That results in a Datapower deployment of affected schema.

Now we are planning to have a restful service that will be called by Datapower for every incoming request and it will return the JSON schema for the service to be invoked and that schema will be present along with service code itself not on Datapower. That way even if there are any changes in service definition, there itself we can make the changes in schema as well and deploy the service. It will save us an unnecessary Datapower deployment.

Is there any better approach to validate the schema? All I want is not to have Datapower deployment for every schema change.

Just FYI we get schema changes on frequent basis.

Answer 1

Keep your current solution as is as pulling in new JSON schemas for every request will affect performance. Instead when you deploy the schema in the backend system have a RMI (REST management interface) or SOMA call that uploads the new schema or simply a XML Firewall where you add a GWS script that writes the json data to file in the directory (requires 7.5 or higher).

Note that you have to clean the cache as well through the call!

Answer 2

A better approach is to have some push system based on subscription to changes. You can store schemas in etcd, redis, postgres or any other system that has notification channels for data changes so you can update schemas in the validating service without doing it on every request. If your validating service uses validator that compiles schemas to code (ajv - I am the author, is-my-json-valid, jsen) it would be even better performance gain if you only do it on change.