[tempo-distributed] Add appProtocol to Enable Tempo Streaming

[msgSend]

Fixes #3281

Enabling streaming on Grafana does not work in certain cases (e.g. Istio) with the tempo-distributed Helm chart despite setting stream_over_http_enabled: true in the config. This is because the appProtocol is not defined in the Kubernetes services and so the gRPC payload is munged.

Relevant Istio reference: https://istio.io/latest/docs/ops/configuration/traffic-management/protocol-selection/#explicit-protocol-selection

[Sheikh-Abubaker]

@msgSend I believe appProtocol is already defined here for both the case could you please checkout if it works the same ?

query-frontend:

helm-charts/charts/tempo-distributed/templates/query-frontend/service-query-frontend.yaml

Lines 27 to 29 in 76d7026

	{{- if .Values.queryFrontend.appProtocol.grpc }}
	appProtocol: {{ .Values.queryFrontend.appProtocol.grpc }}
	{{- end }}

metrics-generator:

helm-charts/charts/tempo-distributed/templates/metrics-generator/service-metrics-generator.yaml

Lines 24 to 26 in 76d7026

	{{- if and (hasPrefix .name "grpc") ($.Values.metricsGenerator.appProtocol.grpc) }}
	appProtocol: {{ $.Values.metricsGenerator.appProtocol.grpc }}
	{{- end }}

[Sheikh-Abubaker]

@msgSend could you please also sign the DCO ?

[msgSend]

@msgSend I believe appProtocol is already defined here for both the case could you please checkout if it works the same ?

query-frontend:

helm-charts/charts/tempo-distributed/templates/query-frontend/service-query-frontend.yaml

Lines 27 to 29 in 76d7026

	{{- if .Values.queryFrontend.appProtocol.grpc }}
	appProtocol: {{ .Values.queryFrontend.appProtocol.grpc }}
	{{- end }}

metrics-generator:

helm-charts/charts/tempo-distributed/templates/metrics-generator/service-metrics-generator.yaml

Lines 24 to 26 in 76d7026

	{{- if and (hasPrefix .name "grpc") ($.Values.metricsGenerator.appProtocol.grpc) }}
	appProtocol: {{ $.Values.metricsGenerator.appProtocol.grpc }}
	{{- end }}

I could not get this to work correctly. I have them set, but I never see them rendered in the service manifest.

[Sheikh-Abubaker]

I could not get this to work correctly. I have them set, but I never see them rendered in the service manifest.

@msgSend No worries! here's how you could utilize the existing appProtocol feature:

In values.yaml set appProtocol.grpc to grpc here for query-frontend and do the similar for metrics-generator here, and it would be automatically rendered in the service manifests for both query-frontend and metrics-generator.

IMPORTANT NOTE: Set metricsGenerator.enabled to true here before setting the above for metrics generator.

[Sheikh-Abubaker]

could you please help me understand the need of setting grpc protocol for a http-metrics port ?