Ballerina is Next WSO2 Gateway language is released recently. APIM also targeted new ballerina language to use for APIM Gateways. Ballerina language is used as integrating various service and have the ability to implement new logic based on that. Which is also have the more advanced feature than apache synapse we have used earlier. The inbuilt connectors allow connecting to the world via many protocols. Which is a graphical modeling programming language which is easy to implement using graphical components.

Ballerina is an awesome programming language which is easy to use for connecting. The following features help it making API management so easy.

• A connector which let to connect services
• In Built utilities function(json, string etc)
• Ballerina composer, help to implement logic graphically
• Ballerina composer’s swagger to ballerina and wise verse code generation Support
• Swagger specification

The above feature available in the Ballerina can be used in APIM to make it easy for users to come up with customizable APIs. unlike the previous releases, we encourage users to update ballerina source to introduce new logic and even resources. Because of the composer feature, it let users implement API resources and mediation logic easily. And also which is more reliable and unwilling for errors. Also, it supports most of the Swagger specification. That means we can write a ballerina service equal to a swagger API. Which feature is used by APIM and it can directly generate API by importing swagger definition. Also in composer which enable to design ballerina or swagger API and generate ballerina or swagger equal source.

To get an idea about ballerina visit ballerina official website and try. There is a tryout editor where you can run your own code there and get the result. Also, you can see there is a different resource which contains about the ballerina. Also, you can visit the ballerina blog(https://medium.com/ballerinalang) which have a list of blogs.

APIM 3.0.0 M1 released recently and which used ballerina as a Gateway. So please refer APIM 3.0.0 official document from here

1. Follow the step below to configure the Gateway.
   • For the API Manager 3.0.0 M1 release, Ballerina runtime is used as the Gateway.
   • Download Ballerina v0.8.1 runtime from here and extract it.
   • Both the Ballerina and WSO2 API Manager runtime servers are required to be hosted in the same for the moment.
   • Since both runtimes are using the same node, offset the Ballerina port by doing the following,
     • Open the <gwHome>/bre/conf/netty-transports.yml file.
     • Change the default port from 9090 to 9091.
     • Set the environment variable gwHome by pointing to the Ballerina home directory.
2. Start the Ballerina runtime server.
   • If gwHome is configured, the Ballerina source for created APIs is generated in the /deployment/org/wso2/apim/ directory.
   • Open the terminal and change the directory to gwHome.
   • Start the Ballerina runtime by giving the relative path to the ballerina sources.

           	$ cd $gwHome
             $ bin/ballerina run service deployment/org/wso2/apim/
           

3. Follow the steps below to invoke an API.
   • Before invoking an API, create and publish an API in the API Publisher.
   • Once a new API is published, the Ballerina server needs to be restarted for the APIs to be deployed. See step 2 above.
   • Subscribe to the API by creating a new application.
   • Make sure you generate an access token for the application.
   • Invoke the API using the following cURL command,

               $ curl -H 'Authorization: Bearer e9352afd-a19d-3d40-9db3-b60e963ae91c' 'http://localhost:9091/hello/'           
               $ Hello World!