Use Redis in the 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. Download the code by choosing the green Code button, and then choosing one of the options to download the code locally.

You can instead run the following command using your CLI at your desired folder location:

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

In this step, you will deploy two functions into the Kyma runtime that were obtained in [Step 1](Clone the Git repository). These resources include:

• cache-order-function.yaml: This function will subscribe to an event published by the Commerce mock application. Once triggered, it will call back to the Commerce mock application to obtain the totalPriceWithTax and then cache the information into Redis.
• get-order-function.yaml: This function will be exposed as an API allowing retrieval of data stored within the Redis cache.

1. In the dev namespace, choose the menu option Overview.

2. Choose Overview > Upload YAML, copy the contents of the file redis-function/k8s/cache-order-function.yaml and then choose Submit.

   

3. Repeat the steps to create the function get-order 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. Choose Create API Rule and provide the value get-order for the Name, Service Name and Host. Choose Create.
   

In this step, you will deploy Redis into the Kyma runtime that were obtained in [Step 1](Clone the Git repository). 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 the menu option Overview.

2. Choose Upload YAML. Upload or copy the contents of the file redis-function/k8s/redis.yaml and choose Submit. Perform the same procedure to upload the contents of the file redis-function/k8s/redis-service.yaml.

3. Choose the menu option Configuration > Secrets. Choose Create Secret and choose the YAML tab. Copy the contents of the file redis-function/k8s/redis-secret.yaml over-writing the preexisting content found within the pane and then choose Create.

4. After completing the deployment of the resources, the Healthy Resources panel found in Overview will report the status of the deployments and the pods they generate. The chart indicates the amount Ready vs the Total. An equal relation means everything is ready.

   

In this step, you will configure the function cache-order, 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 Workloads > Functions.

2. Choose the function cache-order.

3. Choose the Configuration tab and then choose Create Subscription.

   Cache Order

4. In the Create Subscription dialog use the following values as shown in the screenshot and then choose Create

   • Name: order-created
   • Service: cache-order
   • Application name: mp-commerce-mock
   • Event name: order.created
   • Event version: v1

   Add Event

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

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 by clicking on the name value shown in the list.

4. Choose SAP Commerce Cloud - Commerce Webservices.

5. Choose the copy option to copy the Central Gateway URL of the SAP Commerce Cloud - Commerce Webservices. This will be used in the function cache-order.

   

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

1. In the Kyma home workspace, choose Namespace.

2. Choose the dev namespace and choose Workloads > Functions.

3. Choose the function cache-order to open it.

4. Choose the Edit option and scroll down to the Environment Variables and find the Environment Variable with the Variable Name CENTRAL_GATEWAY_URL

5. Paste the value copied in the previous step into the Value field making sure that the value beings with **http://central-application...** and choose Update.

   

6. Choosing Update 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. Choose the Host entry for the commerce-mock APIRule to open it in the browser. 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 function cache-order.

3. Scroll to the bottom of the pane to find the option Replicas of the Function and choose the value found in the table. The name will not match what is shown in the screenshot.

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

   

5. If necessary search for the value orderCode.

6. 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. Choose the Host entry for the get-order APIRule to open the application in the browser. When first opened you will received the message

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

3. Append the value ?orderCode=12331231 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

4. 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.