Fill ALB_NAME with the reader's own load balancers #116

Summary

Add ALB_NAME to the placeholder tokens that docs-vars.js marks for a signed-in reader. Hovering ALB_NAME shows the ALBs in the reader's current project, so they can copy a name or the whole code block filled in, as they already can with your-project-id.

Depends on datum-cloud/cloud-portal#1787 (merged, closes cloud-portal#1786). Instead of adding project.albs to session-status, which holds the navbar loader on every page, the portal now has a separate route:

GET /api/website/projects/:projectId/albs
→ 200 { "items": [{ "name": "...", "displayName": "..." }], "truncated": true }

• Same website group as session-status: exact-origin CORS with credentials, rate limiter, session cookie.
• One metadata-only LIST with the reader's own token, capped at 500 items. truncated: true is set only when the cap was hit.
• displayName comes from the app.kubernetes.io/name annotation (the portal's "chosen name") and is omitted when unset.
• Cached 60 seconds per user, project, and type, so a new ALB can take up to a minute to show.
• Errors: 401 signed out, 403 foreign or missing project, 400 invalid project id, 404 unknown type, 429 rate limited, 502 anything else.

Why

ALB_NAME is one of the most used placeholders in the docs, and the only common one readers still swap by hand:

The MetricsQL queries already fill PROJECT_ID. Without ALB_NAME the copied query still won't run.

Changes

docs-vars.js

• Add ALB_NAME to TOKEN_PATTERN and to the fill() pre-check (it skips any <code> without your-, PROJECT_ID, or ALB_NAME).
• After window.datumSessionStatus resolves with a valid project.name, fetch /api/website/projects/{project}/albs with credentials: 'include' and a timeout. Mark the other tokens first. The ALB fetch must not delay them.
• Keep only entries whose name matches NAME_PATTERN. Treat any non-2xx, network error, or bad body as "no ALBs".
• Add a TIP_COPY['ALB_NAME'] entry ("Your load balancer") with a link to the project's load balancer list in the portal (/project/{project}/alb).
• Hover card:
  • One ALB: works like your-project-id. Shows the value, with Copy value and Copy code with my values.
  • Several ALBs: lists them (name, plus displayName when set). Nothing is selected by default. The reader picks one, and the pick applies to every ALB_NAME on the page. Both copy buttons stay disabled until they pick. This matters on pages like datumctl alb delete ALB_NAME --yes, where a wrong default does real damage.
  • truncated: say the list shows the first 500 and link to the full list in the portal.
  • No ALBs, request failed, or no project: ALB_NAME isn't marked, as today.
• Today values maps each token to one string. ALB_NAME needs a list and a selection, so filledCode() and the copy buttons need to handle that. "Copy code with my values" from another token's card leaves an unpicked ALB_NAME as written.

Content

• alb/operations/overview.mdx uses ALB_NAME in datumctl alb create ALB_NAME ... and in the --display-name row ("If you omit ALB_NAME…"). There it's a new name, so filling it with an existing ALB is wrong. Rename those to NEW_ALB_NAME. The token regex won't match it.
• Check the other uses for the same case.

README.md (Placeholders)

• Add a row: ALB_NAME → one of the reader's ALBs in the current project, chosen on hover when there are several. Use it for an existing load balancer (datumctl alb describe|logs|delete|auth, gateway_name= in metrics).
• Update the rule that lists ALB_NAME as never replaced. Add NEW_ALB_NAME for creating one.

Resolved questions

• Is gateway_name the same as the ALB's HTTPProxy name? Yes. The portal's own metrics query gateway_name with the proxy name (app/features/edge/proxy/metrics/queries.ts in cloud-portal), so the MetricsQL blocks can use ALB_NAME.
• Is the list capped? Yes, at 500, with truncated: true when hit.

Acceptance criteria

• With one ALB in the current project, hovering ALB_NAME shows it, and both copy buttons fill it in
• With several ALBs, the reader must pick one before either copy button works. The pick applies to every ALB_NAME on the page
• With no ALBs, a failed ALB request, or signed out, ALB_NAME stays a plain placeholder with no errors in the console
• The other tokens are marked without waiting for the ALB request
• NEW_ALB_NAME in the create section is never marked
• README Placeholders section updated
• Tested on website.staging.env.datum.net against a staging portal that includes cloud-portal#1787