feat: set loadbalancerIP from Gateway.spec.addresses

[puertomontt]

Description

Motivation:
Users want to be able to set IP of the LoadBalancer Service for a gateway. Gateway API provides Gateway.spec.addresses for this.

Changes:
Use the first Gateway.spec.addresses of type IP to set the loadbalancerIP field of the Service.
Note that although this field is deprecated it is not going to be removed. See here for a good write-up.

Change Type

/kind feature

Changelog

Support Gateway.spec.addresses. We currently support one IP address type value that will be used in the gateway's Service loadbalancerIP.

Additional Notes

Did not add conformance testing as it depends on setting status which we currently don't have a good way to do from the deployer.

[Copilot]

Pull request overview

This PR adds support for setting the LoadBalancer service IP from Gateway.spec.addresses in the Gateway API. When a Gateway specifies an IP address in its spec, and the service type is LoadBalancer, the implementation extracts this IP and sets it as the loadBalancerIP field in the generated Kubernetes Service resource.

Key Changes

• Gateway address extraction: New extractLoadBalancerIP function validates and extracts the first valid IP address from Gateway.spec.addresses where the type is IPAddressType (or nil, which defaults to IPAddressType per Gateway API spec)
• Service generation: Modified GetServiceValues to accept an optional loadBalancerIP parameter and added the field to the HelmService struct
• Helm template updates: Updated both envoy and agentgateway service templates to conditionally render the loadBalancerIP field

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
pkg/kgateway/deployer/gateway_parameters.go	Added extractLoadBalancerIP function with IP validation using netip.ParseAddr, and integrated it into the values generation flow for LoadBalancer-type services
pkg/deployer/values_helpers.go	Updated GetServiceValues signature to accept loadBalancerIP parameter and refactored to safely handle nil svcConfig
pkg/deployer/values.go	Added LoadBalancerIP field to HelmService struct with json omitempty tag
pkg/kgateway/helm/envoy/templates/service.yaml	Added conditional rendering of loadBalancerIP field using Helm with directive
pkg/kgateway/helm/agentgateway/templates/service.yaml	Added conditional rendering of loadBalancerIP field using Helm with directive
test/deployer/testdata/loadbalancer-static-ip.yaml	New test input with Gateway specifying a static IP address (203.0.113.10) in spec.addresses
test/deployer/testdata/loadbalancer-static-ip-out.yaml	Expected Helm output showing the loadBalancerIP field properly set in the generated Service manifest

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[timflannagan]

Can we also enable the conformance test that backs this type of functionality?

[puertomontt]

@timflannagan see "Additional Notes"

[dmitri-d]

lgtm

[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

The function documentation is incomplete. It states that an error is returned "if more than one address is specified or no valid IP address is found", but it doesn't clarify what happens when a single address of a non-IP type (e.g., HostnameAddressType) is provided. The current implementation returns ErrNoValidIPAddress in this case. Consider updating the documentation to explicitly state: "Returns an error if more than one address is specified, if the single address is not of type IPAddress, or if the IP address value is invalid."

Suggested change

	// Returns an error if more than one address is specified or no valid IP address is found.
	// Returns an error if more than one address is specified, if the single address is not of type IPAddress,
	// or if the IP address value is invalid.

[sheidkamp]

I like the changes, definitely cleaner.