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.