Module 1: The developer experience

Select the Developer Hub tab on the right, or open Red Hat Developer Hub at https://backstage-developer-hub-rhdh.{openshift_cluster_ingress_domain}

Log in with your credentials using the OIDC provider:

{user}

{password}

After logging in, you will see the Developer Hub home page. This is the starting point for all developer activity at Parasol.

Take a moment to look around the interface:

Click Catalog in the left sidebar.

Use the Kind dropdown to filter for System entities.

Find and click on parasol-insurance.

Explore the system view:

On the component detail page, explore the tabs:

On the API tile, find the parasol-insurance-api. Click on it, then select the Definition tab.

Click the Lightspeed icon in the bottom-right corner of the Developer Hub interface.

Use the three dots menu in the top-right of the Lightspeed window to switch to full-screen view.

Try asking a question about the Parasol application:

Tell me about the parasol-insurance-api API in the catalog

Review the response. Lightspeed pulls information from the software catalog and documentation to give you contextual answers.

Try another question:

What components make up the parasol-insurance system?

In Developer Hub, click the Self-Service button (the + icon) at the top of the page.

Browse the available software templates. These are golden path templates maintained by the platform team.

Select the Parasol Insurance Development Environment template (or similarly named template).

Fill in the template form:

Click Review to review the details, and then click Create and watch the provisioning progress:

When provisioning completes, click Open in Catalog to see your new component.

On the component page, click View Source to open the feature branch in GitLab.

{user}

{password}

From your component overview page in Developer Hub, click the Open in Dev Spaces link to open a cloud workspace for your feature branch.

The first time Dev Spaces opens, click Log In With OpenShift. You will see several authorization prompts. These are security gates that ensure the IDE only acts with your explicit consent:

Once the workspace loads, take a moment to explore:

Press Ctrl+Shift+P (or Cmd+Shift+P on Mac) to open the command palette.

Type and select Tasks: Run Task.

Select the devfile task group.

Select Start Development Mode (Hot Reload + debug).

Wait for the application to start. When Dev Spaces shows a popup notification to open the application, click to Open In New Tab.

Browse the running Parasol Insurance application:

Back in Dev Spaces, click the Explorer icon in the left sidebar. In the file tree, expand src → main → java → com → parasol.

Right-click on the parasol directory and select New File. Name it ClaimsStatsResource.java.

Copy and paste the following code into the new file:

package com.parasol;

import java.util.HashMap;
import java.util.Map;

import jakarta.inject.Inject;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;

@Path("/api/claims/stats")
@Produces(MediaType.APPLICATION_JSON)
public class ClaimsStatsResource {

    @Inject
    ClaimsResource claimsResource;

    @GET
    public Map<String, Object> getStats() {
        Map<String, Object> stats = new HashMap<>();

        System.out.println("Fetching claim statistics");

        try {
            var claims = claimsResource.getAllClaims();
            stats.put("total", claims.size());

            Map<String, Long> byCategory = new HashMap<>();
            for (var claim : claims) {
                byCategory.merge(claim.getCategory(), 1L, Long::sum);
            }
            stats.put("by_category", byCategory);

            Map<String, Long> byStatus = new HashMap<>();
            for (var claim : claims) {
                byStatus.merge(claim.getStatus(), 1L, Long::sum);
            }
            stats.put("by_status", byStatus);
        } catch (Exception e) {
        }

        return stats;
    }
}

Save the file with Ctrl+S (or Cmd+S on Mac). Quarkus dev mode detects the change and reloads the application — no manual build step required.

In your browser, switch to the tab for the Parasol running application, remove the dashboard.html from the URL and add /api/claims/stats to the end of the URL in the browser’s address bar.

{
  "total": 15,
  "by_category": {
    "auto": 5,
    "home": 4,
    "life": 6
  },
  "by_status": {
    "open": 8,
    "closed": 7
  }
}

In Dev Spaces, click the Source Control icon in the left sidebar (the branch icon).

The new ClaimsStatsResource.java file appears under Changes.

Click the + icon next to the file to stage it.

Enter a commit message in the text field:

Add claims statistics API endpoint

Click the dropdown arrow next to the Commit button and select Commit & Push.

Switch back to Developer Hub in your browser. You may need to log in again if your session has expired:

{user}

{password}

Navigate to your component in the catalog.

Click the CI tab to see the pipeline run that was triggered by your push. (you can ignore any failed GitLab pipelines shown - we are using OpenShift pipelines in this exercise)

Click to expand the pipeline run to see the that the pipeline runs several stages:

Watch the pipeline progress. The sonar-scan stage will fail.

Click on the failed sonar-scan step to see the details.

Find the SonarQube report URL in the pipeline log output.

Open the SonarQube report to see the specific issues:

Switch back to Dev Spaces.

Click the AI assistant icon in the left sidebar.

At the bottom of the chat panel, click the persona selector and choose Code — since we are editing implementation code, not architecting major changes.

In the chat panel, enter this prompt:

The existing ClaimsStatsResource class has
code smells according to SonarQube - please fix them. The
System.out.println, field injection, and empty catch block. Don't
throw any new exceptions, just log it using standard Quarkus logging.

Watch the assistant work. It reads your file, understands that this is a Quarkus project, and applies the fixes directly:

As changes are made by the assistant, you will need to approve them. Click Save to approve each file edit. Remember, the assistant requires your explicit approval before modifying any file.

Once complete, the changes should be in the file. You can also look at diffs via the assistant:

Since LLMs are not deterministic, verify the corrected code looks similar to this:

package com.parasol;

import java.util.HashMap;
import java.util.Map;

import io.quarkus.logging.Log;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;

@Path("/api/claims/stats")
@Produces(MediaType.APPLICATION_JSON)
public class ClaimsStatsResource {

    private final ClaimsResource claimsResource;

    public ClaimsStatsResource(ClaimsResource claimsResource) {
        this.claimsResource = claimsResource;
    }

    @GET
    public Map<String, Object> getStats() {
        Map<String, Object> stats = new HashMap<>();

        Log.info("Fetching claim statistics");

        try {
            var claims = claimsResource.getAllClaims();
            stats.put("total", claims.size());

            Map<String, Long> byCategory = new HashMap<>();
            for (var claim : claims) {
                byCategory.merge(claim.getCategory(), 1L, Long::sum);
            }
            stats.put("by_category", byCategory);

            Map<String, Long> byStatus = new HashMap<>();
            for (var claim : claims) {
                byStatus.merge(claim.getStatus(), 1L, Long::sum);
            }
            stats.put("by_status", byStatus);
        } catch (Exception e) {
            Log.error("Error fetching claim statistics", e);
        }

        return stats;
    }
}

Before committing — you don’t push untested code, right? — switch to the browser tab where the Parasol application is still running and press Ctrl+R (or Cmd+R on Mac) to reload. Quarkus dev mode has already picked up the changes, so you should see the same JSON response at /api/claims/stats as before. If you closed that tab, click the Explorer icon in the left sidebar, then find the ENDPOINTS panel at the bottom and click quarkus-dev (8080/https) to reopen it. If the endpoint returns an error, check the Dev Spaces terminal and adjust the code before continuing.

Commit and push the fix using the Source Control view:

Switch back to Developer Hub and check the CI/CD tab.

A new pipeline run starts automatically.

Watch all stages complete successfully:

In Developer Hub, navigate to your component and click View Source to open the repository in GitLab.

You should see a prompt at the top to Create merge request from your feature branch. Click it.

Review the merge request:

Click Create merge request at the bottom to create the new request. The new request is created and opened for you and others to review.

At this point, the code would normally be reviewed and approved by others, but for now, to merge your changes into the main branch, just click Merge.

In GitLab, navigate back to your parasol-insurance repository (use the project name in the breadcrumb at the top, it should be {user} / parasol-insurance. You can click the GitLab icon at the upper left to see all your repos).

In the left sidebar, click Code, then Tags.

Click New tag.

Fill in the tag details:

Click Create tag.

In GitLab, navigate to the {user}/parasol-insurance-manifests repository.

Click Merge Requests in the left sidebar.

Find the merge request that bumps the Argo CD values to your new tag (1.1). Click on it.

Review the changes — you will see the image tag being updated to reference your new release.

Click Merge to approve the promotion to production.

Switch back to Developer Hub.

Navigate to the Catalog and find the main Parasol Insurance component owned by your user — not the claims-stats branch component. You can click the Owned filter to narrow the list.

Click on the component, then select the Topology tab.

Watch the production environment. It may initially appear red while the new version rolls out. Once the deployment completes, it will turn blue indicating the application is healthy.

Click the small Open icon (the arrow at the upper right of the production application) to open it in a new tab.

Remove the dashboard.html and append /api/claims/stats to the URL and confirm the claims statistics endpoint is returning data in the production environment.