fix: resolve Docker build failures due to undefined template variables and version validation issues

- Add version prefix cleaning logic before validation to handle 'v' prefix from Git tags
- Define BUILD_DATE, BASE_IMAGE, and CLEAN_VERSION template variables before Dockerfile generation
- Add fallback logic for CLEAN_VERSION variable
- Add Dockerfile validation step to check for valid FROM directive
- Add debug logging for template variables and generated Dockerfile content

Fixes issues where:
- Git tags with 'v' prefix (e.g., v0.1.0-beta.16) failed version validation
- Template variables CLEAN_VERSION, BUILD_DATE, and BASE_IMAGE were undefined causing Docker build failures

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: newbe36524

.github/workflows/docker-build.yml

@@ -128,18 +128,30 @@ jobs:
           fi
           echo "version=${VERSION}" >> $GITHUB_OUTPUT
 
+          # Clean version by removing 'v' prefix (for Git tags and other sources)
+          if [[ "${VERSION}" == v* ]]; then
+            CLEAN_VERSION="${VERSION#v}"
+            echo "Removed 'v' prefix from version: ${VERSION} -> ${CLEAN_VERSION}"
+          else
+            CLEAN_VERSION="${VERSION}"
+            echo "Using version as-is (no 'v' prefix): ${VERSION}"
+          fi
+
           # Version format validation (skip for 'latest')
           if [ "${VERSION}" != "latest" ]; then
             # Version must start with a digit and contain only letters, numbers, dots, hyphens, or underscores
-            if ! [[ "${VERSION}" =~ ^[0-9][0-9A-Za-z._-]*$ ]]; then
-              echo "::error::Invalid version format '${VERSION}'"
+            if ! [[ "${CLEAN_VERSION}" =~ ^[0-9][0-9A-Za-z._-]*$ ]]; then
+              echo "::error::Invalid version format '${CLEAN_VERSION}'"
               echo "Version must start with a digit and only contain letters, numbers, dots, hyphens, or underscores."
               echo "Example: 1.2.3, 1.2.3-beta.1"
               exit 1
             fi
-            echo "✓ Version format validated: ${VERSION}"
+            echo "✓ Version format validated: ${CLEAN_VERSION}"
           fi
 
+          # Output CLEAN_VERSION for use in later steps
+          echo "clean_version=${CLEAN_VERSION}" >> $GITHUB_OUTPUT
+
           # Determine platform - default to 'all' if not specified
           if [ -z "${{ inputs.platform }}" ]; then
             # When platform is not specified or empty, default to 'all'
@@ -204,6 +216,37 @@ jobs:
             fi
           fi
 
+      - name: Define Template Variables
+        if: steps.config.outputs.version != 'latest'
+        run: |
+          VERSION="${{ steps.config.outputs.version }}"
+          CLEAN_VERSION="${{ steps.config.outputs.clean_version }}"
+          IMAGE_NAME="hagicode"
+          REGISTRY="${{ secrets.AZURE_ACR_REGISTRY }}"
+
+          # Define build date in ISO 8601 UTC format
+          BUILD_DATE=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
+
+          # Define base image name
+          BASE_IMAGE="${REGISTRY}/${IMAGE_NAME}:base"
+
+          # Ensure CLEAN_VERSION has a fallback value
+          if [[ -z "${CLEAN_VERSION}" ]]; then
+            CLEAN_VERSION="${VERSION}"
+            echo "Using VERSION as CLEAN_VERSION (clean_version output was empty)"
+          fi
+
+          # Output template variables for debugging
+          echo "Template variables:"
+          echo "  CLEAN_VERSION: ${CLEAN_VERSION}"
+          echo "  BUILD_DATE: ${BUILD_DATE}"
+          echo "  BASE_IMAGE: ${BASE_IMAGE}"
+
+          # Set environment variables for the next step
+          echo "CLEAN_VERSION=${CLEAN_VERSION}" >> $GITHUB_ENV
+          echo "BUILD_DATE=${BUILD_DATE}" >> $GITHUB_ENV
+          echo "BASE_IMAGE=${BASE_IMAGE}" >> $GITHUB_ENV
+
       - name: Download and Extract Application
         if: steps.config.outputs.version != 'latest'
         env:
@@ -268,6 +311,23 @@ jobs:
             sed "s|{base_image_name}|${BASE_IMAGE}|g" \
             > output/docker-build-context/Dockerfile.app
 
+          # Verify generated Dockerfile contains valid FROM directive
+          if ! grep -q "^FROM " output/docker-build-context/Dockerfile.app; then
+            echo "::error::Generated Dockerfile is missing FROM directive"
+            echo "This indicates that template variables were not properly substituted."
+            echo "CLEAN_VERSION: ${CLEAN_VERSION}"
+            echo "BUILD_DATE: ${BUILD_DATE}"
+            echo "BASE_IMAGE: ${BASE_IMAGE}"
+            exit 1
+          fi
+
+          # Log generated Dockerfile for debugging
+          echo "Generated Dockerfile:"
+          echo "---"
+          cat output/docker-build-context/Dockerfile.app
+          echo "---"
+          echo "✓ Dockerfile validated successfully"
+
           # Copy application files from download to build context
           cp -r output/download/lib output/docker-build-context/
           # Copy entrypoint script