feat: add --chart-path option to run_demo.sh (#186)

Add support for installing custom Helm charts (e.g., umbrella charts for
extensions) instead of the default diracx chart.

Changes:
- Add --chart-path command-line option to specify a custom chart directory
- Default to ${script_dir}/diracx for backward compatibility
- Update usage documentation with the new option

This enables community extensions (like gubbins, lhcbdiracx) to use their
own umbrella charts that depend on the base diracx chart while leveraging
the run_demo.sh infrastructure.

Note: helm dependency build should be run on the custom chart before calling
this script (typically done in CI configuration).

Author: chrisburr

run_demo.sh

@@ -103,9 +103,11 @@ function element_not_in_array() {
   return $found
 }
 
-usage="${0##*/} [-h|--help] [--exit-when-done] [--offline] [--enable-coverage] [--no-mount-containerd] [--set-value key=value] [--ci-values=values.yaml] [--load-docker-image=<image_name:tag>] [--] [source directories]"
+usage="${0##*/} [-h|--help] [--exit-when-done] [--offline] [--enable-coverage] [--no-mount-containerd] [--set-value key=value] [--ci-values=values.yaml] [--load-docker-image=<image_name:tag>] [--chart-path=path] [--] [source directories]"
 usage+="\n\n"
 usage+="  -h|--help: Print this help message and exit\n"
+usage+="  --chart-path: Path to a custom Helm chart to install instead of the default diracx chart\n"
+usage+="                This is useful for installing umbrella charts that depend on diracx (e.g., extension charts)\n"
 usage+="  --ci-values: Path to a values.yaml file which contains diracx dev settings only enabled for CI\n"
 usage+="  --exit-when-done: Exit after the demo has been started (it will be left running in the background)\n"
 usage+="  --enable-coverage: Enable coverage reporting (used by diracx CI)\n"
@@ -134,6 +136,7 @@ editable_python=1
 open_telemetry=0
 declare -a ci_values_files=()
 declare -a docker_images_to_load=()
+chart_path=""
 
 while [ -n "${1:-}" ]; do case $1 in
   # Print a brief usage summary and exit
@@ -236,6 +239,20 @@ while [ -n "${1:-}" ]; do case $1 in
     shift
     continue ;;
 
+  --chart-path)
+    shift
+    if [[ -z "${1:-}" ]]; then
+      printf "%b Error: --chart-path requires an argument\n" ${SKULL_EMOJI}
+      exit 1
+    fi
+    chart_path=$(realpath "${1}")
+    if [[ ! -d "${chart_path}" ]]; then
+      printf "%b Error: --chart-path does not point to a directory\n" ${SKULL_EMOJI}
+      exit 1;
+    fi
+    shift
+    continue ;;
+
   # Double-dash: Terminate option parsing
   --)
     shift
@@ -601,9 +618,12 @@ done
 
 fi;
 
+# Set the chart path to use (default to the diracx chart in this repository)
+if [[ -z "${chart_path}" ]]; then
+  chart_path="${script_dir}/diracx"
+fi
 
-
-if ! "${demo_dir}/helm" install --debug diracx-demo "${script_dir}/diracx" "${helm_arguments[@]}"; then
+if ! "${demo_dir}/helm" install --debug diracx-demo "${chart_path}" "${helm_arguments[@]}"; then
   printf "%b Error using helm DiracX\n" ${WARN_EMOJI}
   echo "Failed to run \"helm install\"" >> "${demo_dir}/.failed"
 else