helm: make MySQL DB_URL extensible/overridable, wire Grafana datasource envs, and add smoke-test CI

[kahirokunn]

Fixes #340 #349

What changed (approach)

1. Extensible & overridable MySQL DB URL

   • New value: mysql.extraParams (e.g., &tls=skip-verify), appended to the generated DSN.
   • New value: option.assembleDbUrl (default true). When set to false, the chart skips auto-assembly so users can supply DB_URL via lake.envs or an external Secret/ConfigMap.
   • Plumbs DB_CUSTOM_PARAMS via ConfigMap to keep env composition explicit.

2. Grafana datasource picks up MySQL envs

   • Adds option.connectionConfigmapName and wires it into grafana.extraEnvFrom, ensuring the MYSQL_* envs are visible to Grafana for the DevLake datasource initialization.
   • Keeps the default name stable, but allows overriding where installations differ.

3. New GitHub Actions smoke-test (repro & prevention)

   • Spins up a temporary kind cluster, installs the chart with Helm, waits for readiness, and performs basic health checks (Grafana up; MySQL datasource connectable).
   • Runs on every push and PR, acting as a regression guard for the DB/Grafana integration path.

Why this solves the issues

• For It is not possible to extend or overwrite DB_URL #349: Operators can now either (a) stick with auto-assembled DB_URL and append DSN params via mysql.extraParams, or (b) turn off assembly and provide a bespoke DB_URL, unblocking cases where the DSN must be fully controlled.
• For 1.0.2 release broke grafana devlake datasource in the default installation #340: While behavior remains backward-compatible, the chart is now continuously validated end-to-end in CI. The smoke test codifies a working, non-surprising default path and catches regressions early (e.g., broken wiring, missing envs, or datasource init issues).

Backward compatibility

• option.assembleDbUrl: true by default → current installs keep their behavior.
• mysql.extraParams defaults to empty (no change).

New/updated values

mysql:
  extraParams: ""   # e.g., "&tls=skip-verify&autocommit=true"

option:
  assembleDbUrl: true
  connectionConfigmapName: "devlake-mysql-auth-config"

Local verification

I reproduced the scenarios locally and confirmed the chart works end-to-end (install, readiness, and Grafana datasource connectivity) with the changes in this PR.

✅ Result: Works completely in my local environment.

Screenshot (attached):

Notes for reviewers

• CI is intentionally lightweight (kind + Helm) to keep signal high and cost low.

[klesh]

LGTM

[klesh]

Release is failing https://github.com/apache/incubator-devlake-helm-chart/actions/runs/17422005314
Can you help take a look when you find time, thanks.

[kahirokunn]

Hi @klesh ,

I looked into the failing release run https://github.com/apache/incubator-devlake-helm-chart/actions/runs/17422005314. It’s being blocked by our Actions allowlist policy— helm/kind-action@v1.12.0 isn’t currently permitted.

Would you be open to adding helm/kind-action to the allowlist? The helm organization is widely used and trusted in the Kubernetes community, and this action is a straightforward way to provision a local kind cluster for our chart tests.
If adding it isn’t feasible, I can rework the workflow to set up kind/Helm/kubectl via shell steps (or approved/verified actions). That approach will work, though it does introduce a bit more maintenance for future version bumps.

Please let me know which direction you’d prefer—happy to adjust accordingly.
Thanks a lot for your help!

[klesh]

@kahirokunn Thanks for the quick response.
I personally am open the the idea, unfortunately, Apache Policy doesn't allow 3rd party actions.
Can we workaround that?

[kahirokunn]

Okay, I have created a new PR.
I hope you will check it out.
#351

[klesh]

Thank you very much for the quick fix. 👍

[kahirokunn]

Thank you so much for your kind words! I truly appreciate your support.
I’m always grateful for the amazing open-source community, and I’m glad if I can contribute—even in a small way—to making it better together.