chore(ci): compute frontend metadata via script

.github/workflows/service_release_frontend-deploy.yml

@@ -52,17 +52,7 @@ jobs:
     steps:
       - name: Compute image metadata
         id: meta
-        shell: bash
-        run: |
-          set -euo pipefail
-          image_tag="${{ github.event.inputs.image_tag }}"
-          if [[ -z "${image_tag}" ]]; then
-            image_tag="${GITHUB_SHA}"
-          fi
-          ghcr_namespace="${GITHUB_REPOSITORY_OWNER,,}"
-          echo "ghcr_namespace=${ghcr_namespace}" >> "${GITHUB_OUTPUT}"
-          echo "image_tag=${image_tag}" >> "${GITHUB_OUTPUT}"
-          echo "image_ref=ghcr.io/${ghcr_namespace}/dashboard:${image_tag}" >> "${GITHUB_OUTPUT}"
+        run: bash scripts/github-actions/compute-frontend-release-metadata.sh "${{ github.event.inputs.image_tag }}"
 
   build:
     runs-on: ubuntu-latest

scripts/github-actions/compute-frontend-release-metadata.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+IMAGE_TAG_INPUT="${1-}"
+IMAGE_TAG="${IMAGE_TAG_INPUT}"
+if [[ -z "${IMAGE_TAG}" ]]; then
+  IMAGE_TAG="${GITHUB_SHA}"
+fi
+
+GHCR_NAMESPACE="${GITHUB_REPOSITORY_OWNER,,}"
+
+if [[ -z "${GITHUB_OUTPUT-}" ]]; then
+  echo "GITHUB_OUTPUT is not set" >&2
+  exit 1
+fi
+
+{
+  printf 'ghcr_namespace=%s\n' "${GHCR_NAMESPACE}"
+  printf 'image_tag=%s\n' "${IMAGE_TAG}"
+  printf 'image_ref=ghcr.io/%s/dashboard:%s\n' "${GHCR_NAMESPACE}" "${IMAGE_TAG}"
+} >> "${GITHUB_OUTPUT}"