Proxify to webmail only if enabled, related to #40

nginx/Dockerfile

@@ -1,3 +1,5 @@
-FROM nginx
+FROM nginx:alpine
+
+RUN apk add --update nginx-lua && rm -rf /var/cache/apk/*
 
 COPY nginx.conf /etc/nginx/nginx.conf

nginx/nginx.conf

@@ -1,6 +1,6 @@
-user www-data;
+#  Basic configuration
+user nginx;
 worker_processes  1;
-
 error_log /dev/stderr info;
 pid /var/run/nginx.pid;
 
@@ -8,7 +8,11 @@ events {
     worker_connections  1024;
 }
 
+# Environment variables used in the configuration
+env WEBMAIL;
+
 http {
+    # Standard HTTP configuration with slight hardening
     include /etc/nginx/mime.types;
     default_type application/octet-stream;
     access_log /dev/stdout;
@@ -36,10 +40,19 @@ http {
     		return 301 https://$host$request_uri;
     	}
 
+      # Load Lua variables
+      set_by_lua $webmail 'return os.getenv("WEBMAIL")';
+
+      # Actual logic
+
       location / {
+        if ($webmail != none) {
           proxy_pass http://webmail;
         }
 
+        return 403;
+      }
+
       location /admin {
         proxy_pass http://admin;
       }