Switchboard is a port of Gargoyle, a feature flipper for Django apps, to the Pyramid or Pylons stack (including TurboGears). Originally used to selectively roll out changes to the SourceForge site, the library lets you easily control whether a particular change (a switch) is active.
You can make switches active for a certain percentage of visitors, all visitors to a particular host in a cluster, or if a particular string is present in the query string. Furthermore you can easily create your own conditions to do fancier things like geo-targeting, specific users, etc. In short, Switchboard turns you into a continuous deployment ninja.
Switchboard's basic unit is a switch. Every switch has a unique key associated with it and is either active (on) or inactive (off), so using it in code is simple:
>>> from switchboard import operator
>>> operator.is_active('foo')
False
In this case we checked to see if the "foo" switch was active. By default, Switchboard will auto-create any switches that don't already exist, such as "foo". Auto-created switches default to an inactive state.
Whether a switch is active or not is controlled by two attributes: status and condition sets. There are four different statuses:
- Inactive - disabled for everyone
- Selective - active only for matched conditions
- Inherit - inherit from the parent switch
- Global - active for everyone
Inactive and global are opposite extremes: the switch is turned on or off for everyone. The full docs cover parent-child switches, which involves the inherit status. The selective status involves the second attribute, condition sets. When a switch is in seletive status, Switchboard checks the condition sets on the switch to see if it should be active. Conditions are criteria such as "10% of all visitors" or "only logged in users" that can be applied to the request to see if the switch should be active. When a switch is in selective status, it will only be active if it meets the conditions in place.
Switchboard's switches and their condition sets are controlled via the admin UI. Adding switches to your code is as easy as importing the global operator object, as demonstrated above. While there is much more to Switchboard, such as parent-child switches, creating your own conditoion sets, and setting up default settings for certain types of switches, the quick intro above should give you a taste of what it's capable of doing.