Current maintainer: whitehouse
In electronics, a shunt is a device which allows electric current to pass around another point in the circuit by creating a low resistance path.
-- Wikipedia
Shunt module provides a facility for developers to create virtual "shunts" that site administrators can trip in emergency situations, instructing Drupal to fail gracefully where functionality depends on them.
For example, you might create a shunt that disables certain expensive database operations so that in case of an overwhelming traffic event like a denial of service (DOS) attack you have a way of both reducing load on the server and saving legitimate users the frustration of getting white screens or losing form submissions.
This is an API module. It doesn't do anything by itself. Rather, it provides module developers the ability to define shunts and make functionality dependant on them, and it gives site administrators the ability to trip and reset said shunts via the web UI or Drush.
Shunt module is installed in the usual way. See Installing contributed modules.
Shunts can be administered via the web UI at admin/config/development/shunts and tripped and reset there or via Drush. For a list of available Drush commands execute the following:
drush --filter=shunt
For an example of shunt-enabling a module, look at the included Shunt Example module, beginning with its README.