Adds ProviderResource Nil Checks

[danehans]

Adds nil checks for ProviderResources gatewayclasses, gateways, and httproutes.

Fixes #214

Signed-off-by: danehans daneyonhansen@gmail.com

[arkodg]

you probably also want to check if gatewayClasses is nil or not to handle the case when there are no more gateway classes left / the subscribe notification was triggered due to a delete

[arkodg]

imho this should ideally not be happening, but rather than skip it, we should either

• log it or
• return early and empty
  to surface the underlying issue faster

[youngnick]

I agree we shouldn't be seeing nil gateways, so I'd actually be in favor of doing

if gateway == nil {
  // Log some message here
  panic
}

[arkodg]

same as https://github.com/envoyproxy/gateway/pull/216/files#r952032139

[youngnick]

Same for me, I'd rather see a panic than a continue.

[youngnick]

Thanks for finding, I think we should be brutal here and just panic if we get nil values, something has gone seriously wrong, and I'd rather find those cases now before v0.2.0.

[youngnick]

I agree we shouldn't be seeing nil gateways, so I'd actually be in favor of doing

if gateway == nil {
  // Log some message here
  panic
}

[youngnick]

Same for me, I'd rather see a panic than a continue.

[danehans]

@arkodg @youngnick commit b35f07f implements your feedback. However, I am seeing nil gatewayclasses, gateways, and httproutes in my e2e testing so we have an issue elsewhere in the code that must be resolved.

[arkodg]

nit: this is functionally correct, but I still prefer the if ... else if.... else style here, didgolangci-lint suggest this style :) ?

[danehans]

I find switch statements easier to read.

[youngnick]

I missed this before, but switch statements are generally more idiomatic in Go for more than one if statement.

[danehans]

@arkodg I had to rebase. Please retag.