Add gotype comments in templates to map types between go template and go files

[haywoodsh]

Proposed changes

Add gotype comments to specify mapping of types between Go templates (.tmpl) and go files (.go)
closes #4159

Testing

This is the screenshot of how it would look like in IntelliJ or GoLand. For example, $u.Servers links to the field Servers in []StreamUpstreamServer struct

Browse the definition on pkg.dev.go. Note the that information on the website is stuck on v1.12.5 until #3770 is resolved.

Autocomplete:

However, I tested this syntax for IntelliJ and GoLand only. For other unsupported IDE the comments still provide developer hints on which go file to look for the go struct definition.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues found.

Scanned Manifest Files

[codecov]

Codecov Report

Merging #4155 (ad4990d) into main (a820492) will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #4155      +/-   ##
==========================================
+ Coverage   51.95%   51.97%   +0.02%     
==========================================
  Files          59       59              
  Lines       16762    16762              
==========================================
+ Hits         8708     8712       +4     
+ Misses       7755     7753       -2     
+ Partials      299      297       -2     

see 1 file with indirect coverage changes

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[lucacome]

Does this work only in IntelliJ?

[jjngx]

A good idea 👍🏻 VSCode supports this feature too. Apart from IDE support, the comments help to understand the code.

[shaun-nx]

Does this work only in IntelliJ?

You will only get the popups linking to the go structs in IntelliJ.
That being said, it would still help in general to have this in our templates.

For example, for the VirtualServer templates, you would have this block

{{- /*gotype: github.com/nginxinc/kubernetes-ingress/internal/configs/version2.VirtualServerConfig*/ -}}

This makes it very obvious which file in the project holds the go structs related to this template.

[jjngx]

👍🏻

[lucacome]

A good idea 👍🏻 VSCode supports this feature too. Apart from IDE support, the comments help to understand the code.

@jjngx how do you use it in VS Code?

[jjngx]

A good idea 👍🏻 VSCode supports this feature too. Apart from IDE support, the comments help to understand the code.

@jjngx how do you use it in VS Code?

I don't use it.

[vepatel]

I don't think it's supported in vsCode (at least not directly or even with changes in settings.json ) but its nice info re struct definition regardless.