Release
Release is used to indicate a single operation, triggered by kusion apply and kusion destroy, providing users with a more coherent and consistent operation experience with Kusion. Release also provides audit and rollback capabilities, which is currently under development.
Every time kusion apply or kusion destroy is executed, it will trigger the generation of a release file. The combination of a project and workspace corresponds to a set of release files, which also relates to a set of the real application resources. The release file is stored in the same backend as the workspace, and the default path is $HOME/.kusion/releases/$PROJECT_NAME/$WORKSPACE_NAME, whose revision starts from 1 and increments.
The release file contains the Spec and State of an application, both of which are composed of Resources, representing the expected description from the configuration code and the actual state of the resources respectively. In addition, the release file also contains the information of creation and modification time, operation phase, and application metadata, etc.
State
State is a record of an operation's result. It is a mapping between resources managed by Kusion and the actual infra resources. State is often used as a data source for three-way merge/diff in operations like Apply and Preview.
State can be stored in many storage backend mediums like filesystems, S3, and OSS, etc.
Concurrency Control
Release supports collaboration among multiple users and implements the concurrency control through operation phase. When the field of phase in the release file is not succeeded or failed, kusion will not be able to execute kusion apply or kusion destroy operation to the corresponding stack. For example, if a user unexpectedly exits during the kusion apply or kusion destroy process, the phase of the release file may be kept as applying or destroying. In this case, the user can use the command of kusion release unlock to unlock the release file for a specified application and workspace, setting the phase to failed.