feat: throw explicit error when SITE_DOMAIN is unset

- Throw fatal configuration error in src/_data/site.js if SITE_DOMAIN is missing
- Require SITE_DOMAIN in docker-compose.yml without default fallback
- Require SITE_DOMAIN ARG in Dockerfile with no default fallback

Dockerfile

@@ -3,11 +3,11 @@ FROM node:22-alpine AS builder
 
 WORKDIR /app
 
-# Dynamic build arguments for domain & full URL
-ARG SITE_URL=https://riverrooks.dev
-ARG SITE_DOMAIN=riverrooks.dev
-ENV SITE_URL=$SITE_URL
+# Dynamic build arguments for domain & full URL (required, no fallback)
+ARG SITE_DOMAIN
+ARG SITE_URL
 ENV SITE_DOMAIN=$SITE_DOMAIN
+ENV SITE_URL=$SITE_URL
 
 # Copy dependency definitions and install
 COPY package*.json ./

docker-compose.yml

@@ -6,14 +6,14 @@ services:
       context: .
       dockerfile: Dockerfile
       args:
-        SITE_URL: ${SITE_URL:-https://riverrooks.dev}
-        SITE_DOMAIN: ${SITE_DOMAIN:-riverrooks.dev}
+        SITE_DOMAIN: ${SITE_DOMAIN:?Error: SITE_DOMAIN is not set. Please define SITE_DOMAIN in .env}
+        SITE_URL: ${SITE_URL:-https://${SITE_DOMAIN}}
     image: river-rooks-blog:latest
     container_name: river_rooks_web
     restart: unless-stopped
     environment:
-      - SITE_URL=${SITE_URL:-https://riverrooks.dev}
-      - SITE_DOMAIN=${SITE_DOMAIN:-riverrooks.dev}
+      - SITE_DOMAIN=${SITE_DOMAIN:?Error: SITE_DOMAIN is not set. Please define SITE_DOMAIN in .env}
+      - SITE_URL=${SITE_URL:-https://${SITE_DOMAIN}}
     ports:
       - "8080:80"
     healthcheck:

src/_data/site.js

@@ -21,7 +21,17 @@ try {
   // Silent fallback
 }
 
-const siteDomain = process.env.SITE_DOMAIN || "riverrooks.dev";
+const siteDomain = process.env.SITE_DOMAIN;
+if (!siteDomain) {
+  throw new Error(
+    "\n=======================================================================\n" +
+    "FATAL CONFIGURATION ERROR: SITE_DOMAIN environment variable is not set.\n" +
+    "The site domain must be explicitly defined in your .env file or environment.\n" +
+    "Example in .env:\n" +
+    "  SITE_DOMAIN=riverrooks.dev\n" +
+    "=======================================================================\n"
+  );
+}
 const siteUrl = process.env.SITE_URL || `https://${siteDomain}`;
 
 export default {