In some situations it is necessary to display a temporary error or maintenance screen, in order to provide a fallback page when an environment is unavailable.
In order to ensure that this error page is available, it's necessary to create ErrorPages in the CMS with the appropriate error codes. Setup the following (as below) with the codes 500 and 503. This generates the assets/error-500.html and assets/error-503.html files necessary.
These pages will be displayed to the user in the following situations:
- During server error or outage
- During Deployment
Error pages during server error or outage
In the event that the destination environment is completely unavailable, the error-500.html page will be served directly from the gateway. This will also respond to most general server errors.
This page and its assets will be updated regularly to ensure that a cached backup of all necessary files are available.
Note that this page is normally created by default during install.
Error pages during deployment
During the course of certain deployment activities, Silverstripe Cloud will display the error-503.html page for the duration of the process.
From the technical perspective, Silverstripe Cloud creates temporary .htaccess and maintenance.html files. It assumes that the codebase comes with .htaccess, so this is renamed and stored for later retrieval. Websites must not create their own maintenance.html however as this will cause deployments to fail or the file to be destroyed. The maintenance page will either be uploaded from a Silverstripe Cloud template, or created from assets/error-503.html (if available).
.htaccess is then used to redirect all requests to the maintenance page. After the process has completed (or failed) the former .htaccess is restored and maintenance.html removed.