Develop a Ballerina Service

WSO2 Developer Platform allows you to develop and deploy applications using your preferred programming language. This guide demonstrates how to deploy a service component that exposes a REST API using the Ballerina language. No prior knowledge of Ballerina is required to follow this guide.

A REST API is a web service that adheres to Representational State Transfer (REST) principles, using HTTP methods to access and manage resources. This guide walks you through building a Ballerina service component, deploying it on WSO2 Developer Platform, and testing it with an HTTP client application.

In this guide, you will:

• Build a simple greeting service using a sample implementation. The service has a single resource named greet that accepts a query parameter as input.
• Deploy the service in WSO2 Developer Platform.
• Test the service.

Prerequisites

1. If you're signing in to the WSO2 Developer Platform Console for the first time, create an organization:

   • Go to the WSO2 Developer Platform Console and sign in.
   • Enter a unique organization name. For example, Stark Industries.
   • Read and accept the privacy policy and terms of use.
   • Click Create. This creates the organization and opens the Project Home page.

2. Fork the WSO2 Developer Platform samples repository, which contains the sample greetings service implementation in Ballerina.

Learn the repository file structure

It’s important to understand the purpose of key files in the sample service. The table below provides an overview of each file in the greeter service:

note

The file paths are relative to <sample-repository-dir>/greeting-service.

Filepath	Description
service.bal	The greetings service code written in Ballerina.
tests/service_test.bal	Test files related to the service.bal file.
Ballerina.toml	The Ballerina configuration file.

Let’s get started!

Step 1: Create a service component

To create a Ballerina service component, follow these steps:

1. Go to the WSO2 Developer Platform Console and sign in. This opens the Project Home page.

2. If you already have one or more components in your project, click + Create. Otherwise, proceed to the next step.

3. Click the Service card.

4. Click Authorize with GitHub to connect your GitHub account. If you haven’t connected your GitHub repository to WSO2 Developer Platform, enter your GitHub credentials and select the repository you forked in the prerequisites section to install the WSO2 Developer Platform GitHub App.

   note

   The WSO2 Developer Platform GitHub App requires the following permissions:

   • Read and write access to code and pull requests.
   • Read access to issues and metadata.

   You can revoke access if needed. Write access is only used for sending pull requests; WSO2 Developer Platform will not push changes directly to your repository.

5. Provide the following repository details:

   Field	Value
   Organization	Your GitHub account
   Repository	WSO2 Developer Platform-samples
   Branch	main
   Component Directory	/greeting-service

6. Select Ballerina as the build preset.

7. Provide a display name, a unique name, and a description for the service component:

   info

   The Component Name field specifies a unique identifier for the component. This name cannot be changed after creation.

   Field	Value
   Component Display Name	Ballerina Greetings
   Component Name	ballerina-greetings
   Description	Send greetings

8. Click Create. This creates the component and takes you to the Overview page.

You have successfully created a service that exposes a REST API written in Ballerina. Next, let’s build and deploy the service.

Step 2: Build and deploy

Now that you’ve connected the source repository and configured the endpoint details, it’s time to build and deploy the service.

note

If you’re rebuilding the Ballerina service component after changing the Ballerina version, ensure that the version in the Ballerina.toml file matches the version in the Dependencies.toml file.

Step 2.1: Build

To build the service, follow these steps:

1. In the left navigation menu, click Build.

2. On the Build page, click Build Latest.

   note

   Building the service may take a while. Track the progress via the logs in the Build Details pane. Once complete, the build status changes to Success.

Step 2.2: Deploy

To deploy the service, follow these steps:

1. In the left navigation menu, click Deploy.

2. On the Set Up card, click Configure & Deploy.

3. In the Configurations pane, click Next to skip the configuration.

4. Review the Endpoint Details and click Deploy.

   note

   Deploying the service may take a while. Once deployed, the Development environment card shows the Deployment Status as Active.

Once deployed, you can test, manage, and observe the service like any other component in WSO2 Developer Platform.

For detailed instructions, see the following sections:

• Step 3: Test
• Step 4: Manage

Manage the deployment

To view Kubernetes-level insights for detailed diagnosis of this Ballerina REST API, see WSO2 Developer Platform’s DevOps capabilities.