How to Define, user defined policy in IBM Datapower API Gateway?

How to Define, Package and publish a Catalog scoped user-defined policy in IBM Datapower API Gateway?

1. User Defined policy

A policy is a piece of code that implements a specific aspect of processing in the IBM Datapower API Gateway during the handling of an API invocation at Run time.

A User defined policy is a feature of API Connect that lets us create our own policy executed in Datapower Gateway to achieve specific functionality like security, routing, logging, etc. A user-defined policy is of two types

Catalog-scoped user-defined policy – A catalog-scoped user-defined policy is available to the APIS in the specific catalog to which the policy is published.
Global scoped user-defined policy – A global scoped policy is available to all the APIS published in any catalog.

2. Defining Catalog scoped user-defined policy

2.1 Structure of user-defined policy yaml file

YAML Definition	Description
Specification version.	The YAML file policy version.
Information section.	The title, name, version, description, and contact info for the policy.
Attach section.	Whether the policy is applied for REST/SOAP APIs.
Properties section.	Input properties for the policy as seen in the diagram below. The properties section contains the list of properties the policy will declare as required input. The JSON schema defines a root object containing the following JSON properties: type properties required o label: The name value displayed for the property o description: description of the property. o type: integer, string, number, boolean, or array o default (optional): default value. o enum (for properties with a type of string): array of valid values.
Gateways section.	Specify whether the policy is used with the DataPower gateway or any microservices gateway.
Assembly Section	XSLT/Gateway script that needs to be executed will be defined in this section

*Note – Assembly section and properties section are optional sections of the yaml file

3. Packaging Catalog scope user-defined policy

To Package, a catalog scope user-defined policy we need to create a zip file and import the policy into the zip file.
A zip file can contain only 1 yaml file.