Add docker_builder.sh for building PiGallery2 Docker image

This script builds a Docker image for PiGallery2, checking for necessary dependencies and running diagnostics post-build.

Author: bpatrik

docker/docker_builder.sh

@@ -0,0 +1,80 @@
+#!/bin/bash
+# PiGallery2: Build -> Release -> Docker (Debian Trixie) -> Diagnostics
+# This is a helper script for building docker locally. Its a best effort file ans provided as it is, do not expect significant support for this if it gets our of sync from the project. 
+
+set -e # Stop on any error
+
+# Configuration
+REPO_URL="https://github.com/bpatrik/pigallery2.git"
+BUILD_DIR="pigallery2_local_build"
+IMAGE_NAME="pigallery2-custom:local"
+
+echo "--- 1. Pre-flight Environment Check ---"
+
+# Check for Node.js
+if ! command -v node &> /dev/null; then
+    echo "Error: node is not installed. Please install Node.js (v22 recommended)."
+    exit 1
+else
+    NODE_VER=$(node -v)
+    echo "Found Node.js: $NODE_VER"
+fi
+
+# Check for npm
+if ! command -v npm &> /dev/null; then
+    echo "Error: npm is not installed."
+    exit 1
+else
+    NPM_VER=$(npm -v)
+    echo "Found npm: $NPM_VER"
+fi
+
+# Check for Docker (required for the build-docker step)
+if ! command -v docker &> /dev/null; then
+    echo "Error: docker is not installed. Required for building the container."
+    exit 1
+fi
+
+# Check for Git
+if ! command -v git &> /dev/null; then
+    echo "Error: git is not installed."
+    exit 1
+fi
+
+echo "--- 2. Preparing Repository ---"
+if [ -d "$BUILD_DIR" ]; then 
+    echo "Cleaning up old build directory..."
+    rm -rf "$BUILD_DIR"
+fi
+git clone --depth 1 $REPO_URL $BUILD_DIR
+cd $BUILD_DIR
+
+echo "--- 3. Installing Build Dependencies ---"
+# --unsafe-perm handles permission issues during lifecycle scripts (like sharp/libvips)
+npm install --unsafe-perm
+
+echo "--- 4. Creating Production Release ---"
+# This mirrors the GitHub Action workflow you provided
+npm run create-release -- --skip-opt-packages=ffmpeg-static,ffprobe-static --force-opt-packages
+
+echo "--- 5. Building Docker Image (Debian Trixie) ---"
+# Match the Dockerfile expectation: rename 'release' to 'pigallery2-release'
+if [ -d "release" ]; then
+    mv release pigallery2-release
+else
+    echo "Error: Release folder was not created by gulp."
+    exit 1
+fi
+
+# You might need to run this with sudo
+docker build -t $IMAGE_NAME \
+             -f docker/debian-trixie/Dockerfile.build .
+
+echo "--- 6. Running Post-Build Diagnostics ---"
+# The Dockerfile runs diagnostics during build, but this verifies the final image layer
+# You might need to run this with sudo
+docker run --rm $IMAGE_NAME node ./src/backend/index --run-diagnostics --Server-Log-level=silly
+
+echo "------------------------------------------------"
+echo "SUCCESS: $IMAGE_NAME is ready."
+echo "------------------------------------------------"