[tempo-distributed] Add Gateway API support

[DrFaust92]

Summary

• Adds native Gateway API route support (HTTPRoute/GRPCRoute) as an alternative to traditional Ingress resources
• Three route entry points mirror the existing ingress structure: top-level route, gateway.route, and queryFrontend.route
• Includes auto-detection of Gateway API version (v1/v1beta1), mutual exclusivity checks with ingress, and full support for parentRefs, hostnames, matches, filters, timeouts, and additional rules

Closes #296

Test plan

• helm template renders correct HTTPRoute for top-level route with multi-service path routing
• helm template renders correct HTTPRoute for gateway route
• helm template renders correct HTTPRoute for query-frontend route
• Mutual exclusivity: enabling both ingress.enabled and route.enabled produces an error
• Mutual exclusivity: enabling both gateway.ingress.enabled and gateway.route.enabled produces an error
• GRPCRoute kind renders correctly when route.kind: GRPCRoute
• All existing helm-unittests pass

🤖 Generated with Claude Code

[Sheikh-Abubaker]

@DrFaust92 Thanks for the comprehensive implementation is this tested on a live cluster ?

[Sheikh-Abubaker]

port 4318 is not exposed by default unless gateway:

helm-charts/charts/tempo-distributed/values.yaml

Lines 2088 to 2090 in fba349d

	gateway:
	# -- Specifies whether the gateway should be enabled
	enabled: false

and otlp http traces are enabled:

helm-charts/charts/tempo-distributed/values.yaml

Lines 1341 to 1344 in fba349d

	otlp:
	http:
	# -- Enable Tempo to ingest Open Telemetry HTTP traces
	enabled: false

Otherwise the HTTPRoute object states Message: no matching port for Service tempo-distributor and port 4318

Status:
  Parents:
    Conditions:
      Last Transition Time:  2026-04-09T20:12:49Z
      Message:               The route is accepted
      Observed Generation:   1
      Reason:                Accepted
      Status:                True
      Type:                  Accepted
      Last Transition Time:  2026-04-09T20:12:49Z
      Message:               no matching port for Service tempo-distributor and port 4318
      Observed Generation:   1
      Reason:                BackendNotFound
      Status:                False
      Type:                  ResolvedRefs
    Controller Name:         gateway.nginx.org/nginx-gateway-controller

[Sheikh-Abubaker]

To support port 4318, you'd need to gateway and otlp http traces

Suggested change

	route:
	enabled: true
	apiVersion: gateway.networking.k8s.io/v1
	kind: HTTPRoute
	annotations:
	test-annotation: test-value
	labels:
	test-label: test-value
	hostnames:
	- tempo.example.com
	parentRefs:
	- name: my-gateway
	namespace: default
	paths:
	distributor:
	- path: /v1/traces
	pathType: PathPrefix
	port: 4318
	- path: /distributor/ring
	pathType: PathPrefix
	ingester:
	- path: /flush
	pathType: PathPrefix
	query-frontend:
	- path: /api
	pathType: PathPrefix
	compactor:
	- path: /compactor/ring
	pathType: PathPrefix
	traces:
	otlp:
	http:
	enabled: true
	gateway:
	enabled: true
	route:
	enabled: true
	apiVersion: gateway.networking.k8s.io/v1
	kind: HTTPRoute
	annotations:
	test-annotation: test-value
	labels:
	test-label: test-value
	hostnames:
	- tempo.example.com
	parentRefs:
	- name: my-gateway
	namespace: default
	paths:
	distributor:
	- path: /v1/traces
	pathType: PathPrefix
	port: 4318
	- path: /distributor/ring
	pathType: PathPrefix
	ingester:
	- path: /flush
	pathType: PathPrefix
	query-frontend:
	- path: /api
	pathType: PathPrefix
	compactor:
	- path: /compactor/ring
	pathType: PathPrefix

OR just define the default distributor port i.e 3200

Suggested change

	route:
	enabled: true
	apiVersion: gateway.networking.k8s.io/v1
	kind: HTTPRoute
	annotations:
	test-annotation: test-value
	labels:
	test-label: test-value
	hostnames:
	- tempo.example.com
	parentRefs:
	- name: my-gateway
	namespace: default
	paths:
	distributor:
	- path: /v1/traces
	pathType: PathPrefix
	port: 4318
	- path: /distributor/ring
	pathType: PathPrefix
	ingester:
	- path: /flush
	pathType: PathPrefix
	query-frontend:
	- path: /api
	pathType: PathPrefix
	compactor:
	- path: /compactor/ring
	pathType: PathPrefix
	route:
	enabled: true
	apiVersion: gateway.networking.k8s.io/v1
	kind: HTTPRoute
	annotations:
	test-annotation: test-value
	labels:
	test-label: test-value
	hostnames:
	- tempo.example.com
	parentRefs:
	- name: my-gateway
	namespace: default
	paths:
	distributor:
	- path: /v1/traces
	pathType: PathPrefix
	port: 3200
	- path: /distributor/ring
	pathType: PathPrefix
	ingester:
	- path: /flush
	pathType: PathPrefix
	query-frontend:
	- path: /api
	pathType: PathPrefix
	compactor:
	- path: /compactor/ring
	pathType: PathPrefix

[Sheikh-Abubaker]

I tested this change on a KIND cluster configured with NGINX Gateway Fabric controller, the feature is working as intended!