Consider adding a HTTPRouteFilterExtensionRef for Envoy Gateway

[arkodg]

Description:

Describe the desired behavior, what scenario it enables and how it
would be used.

The project has been able to add functionality not yet defined in the Gateway API using Extensions

However some features that naturally live at the rule level within a xRoute that are API specific, dont fit well within Policies such as

• Direct Response Feature Request: Add support for configuring gateway to direct_response on HTTP routes. #2714
• Regex Based Rewrites Support regex based path rewrites #1794
• Body Transformations Support Body Transformations envoy#35783

Adding support for these features in the Gateway API will take time, since building a common API across multiple implementations is not a trivial task, however this is impacting users migrating to Envoy Gateway from other projects who are unable to do so because these common features dont exist yet

Raising this issue to propose adding a new CRD that can be attached to a HTTPRoute rule using the extensionRef field within HTTPRoute https://gateway-api.sigs.k8s.io/reference/spec/#gateway.networking.k8s.io/v1.HTTPRouteFilter

[arkodg]

wdyt @envoyproxy/gateway-maintainers @envoyproxy/gateway-reviewers

[zirain]

for #2714 do we need to wait kubernetes-sigs/gateway-api#2826?

[arkodg]

for #2714 do we need to wait kubernetes-sigs/gateway-api#2826?

yah we can wait or implement this via an extension (highlighted in this PR)

[guydc]

Also consider using this for: #3173

[guydc]

+1 to the filter approach. Would like to see this in 1.2.0.

[zirain]

for #2714 do we need to wait kubernetes-sigs/gateway-api#2826?

yah we can wait or implement this via an extension (highlighted in this PR)

Upstream will not implement it before v1.3(which seems too long), +1 to the filter approach.

[arkodg]

+1, reg naming, HTTPFilter feels like a safe umbrella term to stash all the features under

[zhaohuabing]

+1 on adding an umbrella HTTPFilter to hold all rule-specific features.

[Xunzhuo]

+1 for adding it as an general route level filter

[Alice-Lilith]

+1 for the approach and HTTPFilter