fix(docker): run compression regardless of APP_CONFIG being present ( in cases such as volume mount) (#4673)

.docker/Viewer-v3.x/entrypoint.sh

@@ -7,20 +7,30 @@ if [ -n "$SSL_PORT" ]
     envsubst '${PORT}' < /usr/src/default.conf.template > /etc/nginx/conf.d/default.conf
 fi
 
-if [ -n "$APP_CONFIG" ] ; then
+
+if [ -n "$APP_CONFIG" ]; then
   echo "$APP_CONFIG" > /usr/share/nginx/html${PUBLIC_URL}app-config.js
-  # Removes the old compressed app-config file, then compresses the replacement
-  # and finally creates a new empty file so that gunzip works correctly.
-  # This code is correct despite the AI warning otherwise about order of create/delete
-  rm /usr/share/nginx/html${PUBLIC_URL}app-config.js.gz
-  gzip /usr/share/nginx/html${PUBLIC_URL}app-config.js
-  touch /usr/share/nginx/html${PUBLIC_URL}app-config.js
+  echo "Using custom APP_CONFIG environment variable"
+else
+  echo "Not using custom APP_CONFIG"
 fi
-if [ ! -n "$APP_CONFIG" ]
-  then
-    echo "Not using custom app config"
+
+if [ -f /usr/share/nginx/html${PUBLIC_URL}app-config.js ]; then
+  if [ -s /usr/share/nginx/html${PUBLIC_URL}app-config.js ]; then
+    echo "Detected non-empty app-config.js. Ensuring .gz file is updated..."
+    rm -f /usr/share/nginx/html${PUBLIC_URL}app-config.js.gz
+    gzip /usr/share/nginx/html${PUBLIC_URL}app-config.js
+    touch /usr/share/nginx/html${PUBLIC_URL}app-config.js
+    echo "Compressed app-config.js to app-config.js.gz"
+  else
+    echo "app-config.js is empty. Skipping compression."
+  fi
+else
+  echo "No app-config.js file found. Skipping compression."
 fi
 
+
+
 if [ -n "$CLIENT_ID" ] || [ -n "$HEALTHCARE_API_ENDPOINT" ]
   then
     # If CLIENT_ID is specified, use the google.js configuration with the modified ID