feat: self-hosted postfix

docker-compose.yml

@@ -1,4 +1,3 @@
-version: '3.8'
 services:
   postgres:
     image: postgres:16-alpine
@@ -11,6 +10,37 @@ services:
       - '5432:5432'
     volumes:
       - postgres-data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U newsletter"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+  # Postfix mail server with OpenDKIM for self-hosted email
+  postfix:
+    build: ./docker/postfix
+    container_name: newsletter-postfix
+    restart: always
+    # dns: Uses VPS default DNS. If MX lookups fail, uncomment and set explicit DNS:
+    #   - 213.186.33.99  # OVH DNS
+    environment:
+      - MAIL_DOMAIN=${MAIL_DOMAIN:-example.com}
+      - MAIL_HOSTNAME=${MAIL_HOSTNAME:-mail.example.com}
+      - DKIM_SELECTOR=${DKIM_SELECTOR:-mail}
+    volumes:
+      # Persist DKIM keys across container rebuilds
+      - postfix-dkim:/etc/opendkim/keys
+      # Persist mail queue
+      - postfix-spool:/var/spool/postfix
+    # Port 25 not exposed to host - only accessible within Docker network
+    healthcheck:
+      test: ["CMD-SHELL", "echo 'QUIT' | nc -w 5 localhost 25 | grep -q '220' || exit 1"]
+      interval: 30s
+      timeout: 10s
+      start_period: 10s
+      retries: 3
 
 volumes:
   postgres-data:
+  postfix-dkim:
+  postfix-spool: