Custom Error and Maintenance Pages

Custom Error Pages

Our routers may return an error page in various cases, when an application is unreachable:

• There is no running container.
• The application has no web container running but other types of containers are.
• The application crashed or cut the connection unexpectedly.
• The application timed out.

In these cases, Scalingo’s routers return an error page like the following:

You can customize these pages by modifying the following environment variables:

• SCALINGO_STOPPED_PAGE_URL
• SCALINGO_NO_FRONT_ERROR_URL
• SCALINGO_APP_ERROR_URL
• SCALINGO_TIMEOUT_ERROR_URL

The usage is the following: SCALINGO_STOPPED_PAGE_URL="https://cdn.example.com/stopped_page.html".

In order to prevent the page to be fetched at each request, the content is cached in the router’s memory. Hence we limit the size of this page to 10MB.

Custom Maintenance Page

The SCALINGO_NO_FRONT_ERROR_URL environment can be used to display a specific page when an application is in maintenance. Here are the steps:

1. Set the SCALINGO_NO_FRONT_ERROR_URL environment variable to point to a valid URL containing the maintenance page.
2. Scale down the web containers to 0.
3. Execute all the operations needed for as long as you need. During this step, the maintenance page will be displayed for any request to the application.
4. Scale back up the web containers to the original value.