feat(relay-proxy-helm): add ability to deploy extra manifests

[yafanasiev]

Description

Adds an ability to deploy arbitrary manifests by passing them through the values, with support for templates.
Additionally, added annotation on deployment with configuration ConfigMap checksum so pods are automatically rotated when config is changed, removing the need for manual restart.

Closes issue(s)

Resolve #2196

Checklist

• I have tested this code
• I have added unit test to cover this code
• I have updated the documentation (README.md and /website/docs)
• I have followed the contributing guide

[netlify]

✅ Deploy Preview for go-feature-flag-doc-preview canceled.

Name	Link
🔨 Latest commit	685bd50
🔍 Latest deploy log	https://app.netlify.com/sites/go-feature-flag-doc-preview/deploys/66b4c6767c5d2e00085e4fc9

[thomaspoignant]

Hey, thanks for the PR.
Since I had doubt about this (because it gives the opportunity to anyone to push what they want in the chart), I asked the helm community and they suggested another approach (see here).

What they suggest is:

I think values.yaml should not have extra manifests, rather if someone has requirements to create extra resources, he or she should use this chart as dependency and create their own chart with a template folder having extra manifests.

What do you think about that approach @yafanasiev?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.00%. Comparing base (c2fa4a1) to head (685bd50).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2198   +/-   ##
=======================================
  Coverage   86.00%   86.00%           
=======================================
  Files         102      102           
  Lines        3731     3731           
=======================================
  Hits         3209     3209           
  Misses        399      399           
  Partials      123      123           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[yafanasiev]

@thomaspoignant I can see how it could lead to some issues if you provide broken/conflicting manifests, but that's completely on the end user of the chart. Essentially, chart itself with the default values produces no extra manifests, and user is making a conscious decision populating those extraManifests, and it all happens in the context of his own deployment. Creating a separate chart is quite a step (and you also have to keep in mind added complexity on how helm dependencies work). And for me the culprit here is using the chart with FluxCD/ArgoCD - it is easy to set up a Helm release with a correct set of values, even if some of those are "escape hatches" rather then adding some manifests alongside.

[thomaspoignant]

@yafanasiev I get it, and as I mentioned in the issue I don't have a strong opinion on this one.
We can go with it, I will merge it and it will be available in the next version.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud