feat(charts): add Helm chart for gitks Git bare repository service

- Create Chart.yaml with application metadata and keywords
- Add _helpers.tpl with name, fullname, labels, and DNS template functions
- Generate ConfigMap with all gitks configuration environment variables
- Implement StatefulSet with persistent volume claims for repository data
- Create headless service for pod DNS and cluster communication
- Add gRPC service for client connections and metrics service
- Include HorizontalPodAutoscaler for dynamic scaling
- Add PodDisruptionBudget to maintain cluster availability
- Create ServiceAccount with proper security context
- Add test connection pod using grpcurl for health checks
- Generate NOTES.txt with installation instructions and quick start guide
- Create .helmignore file to exclude common development files
- Configure persistence, resource limits, and security settings
- Add support for cluster mode with etcd service discovery

charts/templates/_helpers.tpl

@@ -0,0 +1,75 @@
+{{/*
+Expand the name of the chart.
+*/}}
+{{- define "gitks.name" -}}
+{{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" }}
+{{- end }}
+
+{{/*
+Create a default fully qualified app name.
+*/}}
+{{- define "gitks.fullname" -}}
+{{- if .Values.fullnameOverride }}
+{{- .Values.fullnameOverride | trunc 63 | trimSuffix "-" }}
+{{- else }}
+{{- $name := default .Chart.Name .Values.nameOverride }}
+{{- if contains $name .Release.Name }}
+{{- .Release.Name | trunc 63 | trimSuffix "-" }}
+{{- else }}
+{{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" }}
+{{- end }}
+{{- end }}
+{{- end }}
+
+{{/*
+Headless service name (used for StatefulSet pod DNS).
+*/}}
+{{- define "gitks.headlessServiceName" -}}
+{{- printf "%s-headless" (include "gitks.fullname" .) | trunc 63 | trimSuffix "-" }}
+{{- end }}
+
+{{/*
+Create chart name and version as used by the chart label.
+*/}}
+{{- define "gitks.chart" -}}
+{{- printf "%s-%s" .Chart.Name .Chart.Version | replace "+" "_" | trunc 63 | trimSuffix "-" }}
+{{- end }}
+
+{{/*
+Common labels
+*/}}
+{{- define "gitks.labels" -}}
+helm.sh/chart: {{ include "gitks.chart" . }}
+{{ include "gitks.selectorLabels" . }}
+{{- if .Chart.AppVersion }}
+app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}
+{{- end }}
+app.kubernetes.io/managed-by: {{ .Release.Service }}
+{{- end }}
+
+{{/*
+Selector labels
+*/}}
+{{- define "gitks.selectorLabels" -}}
+app.kubernetes.io/name: {{ include "gitks.name" . }}
+app.kubernetes.io/instance: {{ .Release.Name }}
+app.kubernetes.io/component: server
+{{- end }}
+
+{{/*
+Create the name of the service account to use
+*/}}
+{{- define "gitks.serviceAccountName" -}}
+{{- if .Values.serviceAccount.create }}
+{{- default (include "gitks.fullname" .) .Values.serviceAccount.name }}
+{{- else }}
+{{- default "default" .Values.serviceAccount.name }}
+{{- end }}
+{{- end }}
+
+{{/*
+Pod DNS name template: pod-name.headless-svc.namespace.svc.cluster.local
+*/}}
+{{- define "gitks.podDnsTemplate" -}}
+$(STORAGE_NAME).{{ include "gitks.headlessServiceName" . }}.{{ .Release.Namespace }}.svc.cluster.local
+{{- end }}