Use Redis in SAP BTP, Kyma Runtime to Store and Retrieve Data

1. Go to the kyma-runtime-extension-samples repository. This repository contains a collection of Kyma sample applications which will be used during the tutorial.

2. Use the green Code button to choose one of the options to download the code locally, or simply run the following command using your CLI at your desired folder location:

   Shell/Bash Copy

   git clone https://github.com/SAP-samples/kyma-runtime-extension-samples

1. Open Kyma dashboard using the Dashboard URL link in SAP BTP cockpit.

2. Choose Modify Modules, and select Add.

3. In the Add Modules section, check eventing, nats, and serverless, and select Add.

You can find more info in Add and Delete a Kyma Module.

When you add the Eventing module, you must configure a backened for it. Follow these steps:

1. In your Modules section, go to eventing, and choose Edit.

2. In Backend Type, choose NATS from the dropdown, and select Save.

You can find more info in Choose a Backend for Kyma Eventing.

In this step, you will deploy the Redis resources, obtained in Step 1, into SAP BTP, Kyma runtime. These resources include:

• redis.yaml: The deployment defining the Redis cache configuration.
• redis-service.yaml: The Kubernetes Service which exposes the Redis instance to the two Serverless Functions.
• redis-secret.yaml: The Kubernetes Secret which defines the Redis password.

1. In the dev namespace, choose Upload YAML and upload or copy the contents of the redis-function/k8s/redis.yaml file, and click Upload.

2. Perform the same procedure to upload the contents of the redis-function/k8s/redis-service.yaml file.

3. Go to Configuration > Secrets, and choose Create.

4. Switch to the YAML tab, and copy the contents of the redis-function/k8s/redis-secret.yaml file over-writing the preexisting content found within the pane, and then choose Create.

In this step, you will deploy two Functions into SAP BTP, Kyma runtime that were obtained in Step 1. These resources include:

• cache-order-function.yaml: This Function subscribes to an event published by the commerce mock application. Once triggered, it calls back to the commerce mock application to obtain the totalPriceWithTax and then cache the information into Redis.
• get-order-function.yaml: This Function is exposed as an API allowing retrieval of data stored within the Redis cache.

1. In the dev namespace, choose Upload YAML, and upload or copy the contents of the redis-function/k8s/cache-order-function.yaml file.

2. Change the Node.js version to nodejs20 by adjusting the value of spec.runtime, and click Upload.

3. Repeat the steps to create the get-order Function using the file redis-function/k8s/get-order-function.yaml.

1. To expose the get-order Function as an API, choose the menu option Discovery and Network > API Rules, and click Create.
2. Provide the value get-order for Name, Service Name and Host.
3. Select No Auth for Access Strategy, and choose Create.

In this step, you will configure the cache-order Function, deployed in the previous step, to run when the order.created event is fired from the commerce mock application.

1. In the dev namespace, choose Configuration > Subscriptions.

2. Choose Create, and use the following values:

   • Name: order-created
   • Types: order.created.v1
   • Service: cache-order
   • Source: mp-commerce-mock

In this step, you will copy the URL to the commerce web services API which will be used by the cache-order Function.

1. Choose the menu option Back to Cluster Details to go back to the Kyma home workspace.

2. In the Kyma home workspace, choose Integration > Applications.

3. Choose the mp-commerce-mock application.

4. Choose SAP Commerce Cloud - Commerce Webservices.

5. Choose the Copy to Clipboard option to get the Central Gateway URL of the SAP Commerce Cloud - Commerce Webservices. This will be used in the cache-order Function.

In this step, the URL copied in the previous step will be assigned to an environment variable of the cache-order Function. This allows the Function to call the SAP Commerce Cloud - Commerce Webservices of the commerce mock application.

1. Go to the dev namespace, and choose Workloads > Functions.

2. Choose the cache-order Function to open it.

3. Choose Edit, scroll down to Environment Variables and find the Environment Variable with the Variable Name CENTRAL_GATEWAY_URL.

4. Paste the value copied in the previous step into the Value field. Make sure that the value begins with http://central-application... and choose Save.

5. Choosing Save will cause the Function to be rebuilt and deployed. The Status field will indicate that the Function is Deploying and will change to Running once this process completes.

With the configuration steps completed, you can now test the scenario to validate that it is working as intended.

1. Open the mock application in the browser by choosing Discovery and Network > API Rules from the menu.

2. Paste the Hosts entry for the commerce-mock APIRule to your browser and press Enter. This URL should be similar to: https://commerce.*******.kyma.ondemand.com

3. Choose the Remote APIs tab.

   

4. Choose the SAP Commerce Cloud - Events option.

5. For the Event Topics, choose order.created.v1.

6. Modify the orderCode value as desired and choose Send Event. Make sure to remember the orderCode value, it will be used in a later step.

   

In this step, we will view the logs outputted by the Function to verify that the scenario is working.

1. In the dev namespace, choose Workload > Functions.

2. Choose the cache-order Function.

3. Scroll to the bottom of the pane to find the option Replicas of the Function and choose the value found in the table.

   

4. Under Containers, choose View Logs for the function container.

   

5. The output should be similar to:

   

In this step, we use the get-order Function to perform a read request of the data cached in the Redis database.

1. Choose Discovery and Network > API Rules from the menu.

2. Paste the Hosts entry for the get-order APIRule to your browser and press Enter. When opened for the first time, you will receive the message:

   {"error":"No orderCode received!"}

3. Append the value ?orderCode={YOUR_ORDER_CODE} to the URL where the value is the same as used when sending the event, for example:

   https://get-order.*********.kyma.ondemand.com/?orderCode=1231231

This should output the value saved when the event was submitted.

`{"orderCode":"1231231","Date":"Tue Nov 17 2020 19:28:42 GMT+0000 (Coordinated Universal Time)","Value":"100"}`

Congratulations! You have successfully completed the mission.