Add Helm dashboard configMap sources + conversion script

Signed-off-by: Eero Tamminen <eero.t.tamminen@intel.com>

Author: eero-t

helm-charts/common/dashboard/json/README.md

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+# Generating Grafana dashboard Helm chart configMap templates
+
+User would need to manually load Grafana dashboard JSON file, but
+when Helm Dashboard chart installs it to Grafana namespace inside a
+suitably labeled configMap, Grafana will load it automatically.
+
+Here are the dashboard JSON spec files used as sources for those
+configMaps. After dashboard is updated in Grafana, it can be saved
+again to a JSON file here, and the corresponding configMap updated
+with the provided conversion script.
+
+Usage:
+
+```
+cd ../templates/
+../json/convert-dashboard.sh ../json/*.json
+```

helm-charts/common/dashboard/json/convert-dashboard.sh

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+#!/bin/sh
+#
+# Copyright (C) 2025 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+set -e
+
+# OPEA CI requires copyright/license for the converted file
+COPYRIGHT="Copyright (C) 2025 Intel Corporation"
+LICENSE="SPDX-License-Identifier: Apache-2.0"
+
+# Label needed in configMap to get (Helm installed) Grafana to load it as dashboard
+LABEL="grafana_dashboard=1"
+
+# needs to be specified so there's something to override
+NS="default"
+
+error_exit ()
+{
+	name=${0##*/}
+	cat << EOF
+
+ERROR: $1!
+
+Convert given Grafana *.json dashboard specs to Grafana dashboard configMap
+templates compatible with OPEA Dashoard Helm chart.
+
+Dashboard 'title' and 'uid' are overridden with values composed of
+the OPEA Dashboard Helm chart values and file name, similarly to
+the produced configMap name and namespace.
+
+Usage:
+	$name <JSON files>
+
+ERROR: $1!
+EOF
+	exit 1
+}
+
+if [ -z "$(which jq)" ]; then
+	error_exit "'jq' required for dashboard checks, please install 'jq' first"
+fi
+
+if [ -z "$(which kubectl)" ]; then
+	error_exit "'kubectl' required for dashboard conversion, please install 'kubernetes-client' first"
+fi
+
+if ! kubectl version; then
+	error_exit "Broken/missing 'kubectl' cluster config (script does not need it, but kubectl still fails)"
+fi
+
+uid=""
+title=""
+
+echo
+echo "Got following Grafana dashboards:"
+for file in "$@"; do
+	if [ ! -f "$file" ]; then
+		error_exit "JSON file '$file' does not exist"
+	fi
+	if [ "${file%.json}" = "$file" ]; then
+		error_exit "JSON file '$file' does not exist"
+	fi
+
+	# Both dashboard 'uid' and title needed
+	uid=$(jq .uid "$file" | tail -1 | tr -d '"')
+	if [ -z "$uid" ]; then
+		error_exit "'$file' dashboard has invalid JSON"
+	elif [ "$uid" = "null" ]; then
+		error_exit "'$file' dashboard has no 'uid' field (will be replaced with Helm variable)"
+	fi
+
+	# ...but it should have a title.
+	title=$(jq .title "$file" | tail -1 | tr -d '"')
+	if [ "$title" = "null" ]; then
+		error_exit "'$file' dashboard has no 'title' field (will be replaced with Helm variable)"
+	fi
+
+	echo "- file: $file, uid: '$uid', title: '$title'"
+done
+
+echo
+echo "Converting:"
+for file in "$@"; do
+	base=${file##*/}
+	name=${base%.json}
+	dst="configmap-${name}.yaml"
+
+	uid=$(jq .uid "$file" | tail -1 | tr -d '"')
+	title=$(jq .title "$file" | tail -1 | tr -d '"')
+
+	# convert to k8s object name ("[a-z0-9][-a-z0-9]*[a-z0-9]"):
+	# - upper-case -> lowercase, '_' -> '-'
+	# - drop anything outside [-a-z]
+	# - drop '-' prefix & suffix and successive '-' chars
+	k8name=$(echo "$name" | tr A-Z_ a-z- | tr -d -c a-z- | sed -e 's/^-*//' -e 's/-*$//' -e 's/--*/-/g')
+
+	echo "- $base -> $dst"
+
+	echo "{{- if .Values.$name }}" > "$dst"
+
+	echo "# $COPYRIGHT" >> "$dst"
+	echo "# $LICENSE" >> "$dst"
+	echo "#" >> "$dst"
+	echo "# ${0##*/}: $base -> $dst" >> "$dst"
+
+	kubectl create cm -n "$NS" --from-file "$file" --dry-run=client -o yaml "$k8name" |\
+	  kubectl label -f- --local --dry-run=client -o yaml "$LABEL" |\
+	  grep -v -e "^  creationTimestamp:" >> "$dst"
+
+	echo "{{- end }}" >> "$dst"
+
+	# convert JSON content conflicting with Helm to Helm compatible format
+	# and add suitable Dashboard chart Helm variables to the configMap
+	sed -i \
+	  -e 's/\({{[a-z]\+}}\)/{{ printf "\1" }}/' \
+	  -e 's/name:.*$/name: {{ include "dashboard.fullname" . }}'"-${k8name}/" \
+	  -e 's/space:.*$/space: {{ .Values.global.prometheusNamespace }}/' \
+	  -e "s/${title}/{{ .Values.prefix }} $name/" \
+	  -e "s/${uid}/opea-"'{{ include "dashboard.fullname" . }}'"-${k8name}/" \
+	  "$dst"
+done
+
+echo
+echo "DONE!"