Trace-to-logs link ignores Grafana root URL (appSubUrl) configuration #784

Description

When navigating from a trace span to logs, the generated link does not respect the Grafana root_url configuration. When Grafana is deployed under a sub-path (e.g., http://example.com/grafana), the logs drilldown link is missing the appSubUrl prefix, resulting in a 404.

Steps to Reproduce

1. Configure Grafana's root_url to include a sub-path (e.g., http://example.com/grafana)
2. Open Traces Drilldown and view a trace by its ID
3. Click a link from a span to navigate to logs
4. Observe that the link is missing the /grafana prefix and fails to navigate

Expected Behavior

The link should include the appSubUrl prefix, e.g.: /grafana/a/grafana-lokiexplore-app/explore?...

Actual Behavior

The link is missing the prefix, e.g.: /a/grafana-lokiexplore-app/explore?...

Root Cause

In DataLinksCustomContext.tsx, the path returned by the Logs Drilldown plugin via the grafana-exploretraces-app/get-logs-drilldown-link/v1 extension point is assigned directly to linkModel.href without prepending config.appSubUrl.

Other navigation links in the codebase (e.g., PanelMenu.tsx, SpanListScene.tsx) correctly prepend config.appSubUrl:

const subUrl = config.appSubUrl ?? '';
const url = urlUtil.renderUrl(`${subUrl}/explore`, { ... });

Fix

Prepend config.appSubUrl to extensionLink.path before assigning it to linkModel.href in DataLinksCustomContext.tsx:

// Before
linkModel.href = extensionLink.path;

// After
const subUrl = config.appSubUrl ?? '';
linkModel.href = `${subUrl}${extensionLink.path}`;

Affected Files

• src/pages/Explore/DataLinksCustomContext.tsx
• src/pages/Explore/DataLinksCustomContext.test.tsx