feat: pass engineLabels to workerGroup

[JustinDuy]

FILL IN THE PR DESCRIPTION HERE

FIX [https://github.com//issues/751]

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[gemini-code-assist]

Summary of Changes

Hello @JustinDuy, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request implements a new feature that allows custom engine labels to be propagated to the worker group pods when deploying a Ray cluster via Helm. This enhancement addresses issue #751 by providing greater control over Kubernetes resource labeling, which can be beneficial for scheduling, monitoring, and organizing engine-specific deployments.

Highlights

• Feature: Engine Labels: Introduced the capability to pass engineLabels to the worker group configuration within the Ray cluster Helm chart. This allows for custom labels to be applied to engine pods.
• Kubernetes Resource Management: This change enhances the flexibility of managing and identifying engine-specific resources in a Kubernetes environment by enabling more granular labeling of pods.

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[gemini-code-assist]

Code Review

This pull request adds the engineLabels from servingEngineSpec to the worker group pods in the RayCluster definition. The change is straightforward and correctly applies the existing chart.engineLabels helper to achieve this. I've added one comment regarding a potential issue with the chart.engineLabels helper that could cause template rendering to fail with certain values.yaml configurations. While it's a pre-existing issue, it would be good to address it to improve the chart's robustness.

[gemini-code-assist]

While this change correctly uses the existing chart.engineLabels helper, this helper has a potential flaw. If .Values.servingEngineSpec.labels is defined as an empty map (e.g., labels: {} in values.yaml), the toYaml function within the helper will render {}. This results in invalid YAML for the pod labels, causing Helm to fail during template rendering.

To make the chart more robust, I recommend improving the chart.engineLabels helper in helm/templates/_helpers.tpl. A safer implementation would be to iterate through the labels, which correctly handles an empty map.

Here is a suggested implementation for the helper:

{{- define "chart.engineLabels" -}}
{{- range $key, $value := .Values.servingEngineSpec.labels }}
{{ $key }}: {{ $value | quote }}
{{- end }}
{{- end }}

Since this is a pre-existing issue and you are following an established pattern, this is not a blocker for this PR. However, addressing this would be a valuable improvement for the chart's stability.