Timeline¶
Service Name: Services::TIMELINE
This service provides an instance of BaleenMigrationsTimeline
and sets its Comparator. Since this
service almost exclusively relies on other services in the framework, migration libraries will hardly ever need to
replace this service.
By default a special factory is used to instantiate the Timeline. The factory is an instance of
TimelineFactory
. When instantiating a Timeline, the factory creates a collection of available migrations by
“enriching” the migrations available in the Repository service with the state data available from the
Storage service. In the process, it also makes sure that there’s no missing migration files in the Repository
(e.g. a version that is reported as migrated in the Storage but that has no corresponding file in the Repository).
In Baleen CLI the default TimelineProvider
provides also the Services::COMPARATOR
service.
Refer to the Comparator page for more information.