Creating and Testing Serverless Functions

Business Scenario

You are a developer and must create an API to receive and process data. You have heard of the approach to use serverless functions to implement such an API. Furthermore, you want to learn how to create a serverless function and how to use it.

Exercise Options

You can perform this exercise in two ways:

Platform Simulation – follow the step-by-step instructions within the simulation.
Live Environment - by using the instructions provided below, you can perform the steps in the SAP BTP Free Tier account.

Note

We strongly recommend first performing the steps in the Live Environment.

Platform Simulation

Choose the Start Exercise button below to open a simulation of the platform. Then follow the step-by-step instructions to create and test a serverless function.

ExerciseStart Exercise

Live Environment

In this exercise, you will perform the following steps:

Create a serverless function via kubectl.
Create a serverless function via the Kyma Dashboard.
Expose and test the function via HTTP.

Prerequisites

You have successfully created a SAP BTP, Kyma runtime instance in the SAP BTP subaccount.
You have configured kubectl to work with your SAP BTP, Kyma runtime instance.

Task 1: Create a serverless function via kubectl

Steps

Create a serverless function via kubectl.
1. Open your terminal and list all current serverless functions in your default namespace:
  Code snippet
  kubectl get functions
  Copy code
  Your namespace has no functions, so it should return an empty list.
2. Create a serverless function using the following command:
  Code snippet
  kubectl apply -n default -f https://raw.githubusercontent.com/kyma-runtime-learning-journey/main/unit_3/functions/hello-world-function.yaml
  Copy code
3. List all serverless functions in your namespace again:
  Code snippet
  kubectl get functions
  Copy code
  You should see the function you just created.
Create a Serverless Function via the Dashboard.
Use the following data:
Field Value
Name hello-kyma-function
Runtime Node.js 14
Source Inline editor
1. Open the Kyma Dashboard and navigate to the functions workload view.
2. Select your default namespace in the namespace dropdown menu.
3. Choose the Create Function button.
  A pop-up window opens.
4. Enter the information from the table above into the Advanced tab.
  You can also check the YAML tab to see, copy or edit the YAML manifest of the function.
5. Choose the Create button.
  Your function is now being created.
Expose and test the function via HTTP.
Note
We expose the function via HTTP so that we can test it via a browser. You will find out more about exposure later in the course.
Use the following data:
Field Value
Name hello-kyma-function-api
Service hello-kyma-function (port: 80)
1. Navigate to Service Discovery → API Rules and choose Create API Rule.
  This opens a pop-up window.
2. Enter the following information on the Simple tab and choose on the Create button:
  This will expose your function as an HTTP endpoint. Only GET requests are allowed.
3. Navigate back to the Function Workloads view and open the hello-kyma-function function.
4. Open the endpoint URL in your browser and choose the URL in the API Rules view.
5. You should see the following message:
  Hello World from the Kyma Function main running on nodejs14!