feat: add generic playwright-cloud reusable workflow for Cloud E2E tests

[adamyeats]

This PR adds .github/workflows/playwright-cloud.yml, a reusable workflow for running Playwright E2E tests against a shared Grafana Cloud instance via Grafana Bench. The workflow is generic and can be called from any datasource plugin repo.

Data source-specific Vault secrets, Grafana URL, Bench commands, Bench version, and service version are all configurable via inputs. Act tests are included to validate the happy path and the fork-skip condition.

Usage in a calling repo

Create a workflow file (e.g. .github/workflows/cron.yml) in your datasource repo:

name: Scheduled Cloud E2E tests

on:
  schedule:
    - cron: '0 6 * * *'
  workflow_dispatch:

jobs:
  playwright-cloud:
    uses: grafana/plugin-ci-workflows/.github/workflows/playwright-cloud.yml@main
    secrets: inherit
    with:
      repo-secrets: |
        DS_INSTANCE_HOST=my-datasource/instance:host
        DS_INSTANCE_PASSWORD=my-datasource/instance:password
        DS_INSTANCE_PORT=my-datasource/instance:port
        DS_INSTANCE_USERNAME=my-datasource/instance:username

The keys on the left side of each = become environment variables inside the Bench container and are forwarded to the Playwright process. The values on the right are Vault paths in the format vault-secret-name:field.

If your datasource uses Private Data Source Connect, pass the PDC network name via the pdc-network-name input.

Deploying the plugin to the Cloud E2E instance

To deploy a plugin to the datasourcese2e instance on push to main, use cd.yml directly:

jobs:
  cd:
    uses: grafana/plugin-ci-workflows/.github/workflows/cd.yml@main
    with:
      environment: dev
      scopes: grafana_cloud_instance_datasourcese2e
      grafana-cloud-deployment-type: provisioned
      trigger-argo: true

[cla-assistant]

All committers have signed the CLA.

[adamyeats]

This is awaiting https://github.com/grafana/deployment_tools/pull/519206, and once it's merged, it'll be ready for review.

[adamyeats]

Closing in favour of https://github.com/grafana/data-sources/pull/1095. I think, as written, these plugins are not generic enough to add to this repo. We'll add these to data-sources for now, and maybe circle back to moving them here in future if that seems like the right call.