attribute transitional

If true, the first two rotation option sets are swapped when building message encryptors. For example, with the following configuration, message encryptors will encrypt messages using serializer: Marshal, url_safe: true, and will able to decrypt messages that were encrypted using any of the three option sets:

encryptors = ActiveSupport::MessageEncryptors.new { ... }
encryptors.rotate(serializer: JSON, url_safe: true)
encryptors.rotate(serializer: Marshal, url_safe: true)
encryptors.rotate(serializer: Marshal, url_safe: false)
encryptors.transitional = true

This can be useful when performing a rolling deploy of an application, wherein servers that have not yet been updated must still be able to decrypt messages from updated servers. In such a scenario, first perform a rolling deploy with the new rotation (e.g. serializer: JSON, url_safe: true) as the first rotation and transitional = true. Then, after all servers have been updated, perform a second rolling deploy with transitional = false.