Gateway API Enhancement Proposal Tracker

[kate-osborn]

This discussion is to track the Gateway API Enhancement Proposals (GEPs) that NGF will need to implement.

GEP	GEP Status	Notes	NGF Status
Backend mTLS	Implementable	NGINX can support natively. Optional support for SPIFFE, which could be useful for E/W use cases.	To Do
HTTPRoute Retries	Implementable	NGINX will need a custom module to implement GEP.	To Do
Percentage-based Request Mirroring	Implementable	NGINX can support natively using split_clients.	To Do
Query Parameter Filter	Experimental	NGINX should be able to support this using set and rewrite.	To Do
HTTP Cookie Match	Experimental	Using our njs matching script, we should be able to read the Cookie header.	To Do
ListenerSets	Open	NGINX will be able to support. See ListenerSets section below for more notes.	To Do

ListenerSets

• We may need to support (parent) Gateways with no listeners defined. The GEP proposes loosening the schema validation (removing minItems=1). This could break our implementation if we rely on at least one listener existing. Also, this may affect how we write the Gateway status. If no listeners are present, they propose leaving status.listeners unset. Finally, we will have to figure out what to do once we support provisioner mode. Do we provision a data plane if a Gateway doesn't have any listeners? GEP leaves that up to the implementor to decide.
• This GEP lists many "potential future goals" that could affect NGF, such as removing TLSRoute. We will need to monitor this GEP as it proceeds through the GEP process.
• This GEP is complex but similar to the route attachment concept, hopefully making it easier for us to implement and for users to understand.
• Separate discussion happening around policy attachment and ListenerSets: Further changes to Policy Attachment kubernetes-sigs/gateway-api#2927. We should also monitor this.