Disclaimer: These are planning documents. The functionalities described
here may be unimplemented, partially implemented, or implemented differently
than the original design.
Scribe for Scabbard v0.7
Summary
The scribe component is part of the new service API that will be used in Scabbard v0.7. This component will create and execute commands derived from an artifact.
Guide-level explanation
The diagram below shows the sequence of a coordinator creating a new scribe instance and giving it an artifact to interpret and store in the database.
The scribe component includes an ArtifactStoreCommandGenerator, this generator
will produce the following types of StoreCommands: prepare, commit, and
rollback. The prepare StoreCommand, when executed, will store the related data
in the database in a staged state. The commit StoreCommand will commit
prepared data, putting it in an active state. The rollback StoreCommand will
delete uncommitted data from the database.
sequenceDiagram
participant c as coordinator
participant S as Scribe
participant A as ArtifactStoreCommandGenerator
participant SCE as StoreCommandExecutor
rect rgb(192, 192, 192)
Note right of c: New Scribe is created
c ->>+ S: new(ArtifactStoreCommandGenerator)
S -->>- c: Result<Scribe, Err>
end
rect rgb(192, 192, 192)
Note right of c: Scribe prepares data
c ->> S: prepare(Scope, Artifact, StoreCommands)
activate S
S ->>+ A: get_prepare_command(Artifact)
Note right of A: PrepareCommand implements
StoreCommand A -->>- S: Result<PrepareCommand, Err> S ->>+ StoreCommandExecutor: execute(StoreCommands) StoreCommandExecutor -->>- S: Result<(), Err> S -->> c: Result<(), Err> end rect rgb(192, 192, 192) Note right of c: Scribe commits prepared data c ->> S: commit(Scope, StoreCommands) S ->>+ A: get_commit_command() Note right of A: CommitCommand implements
StoreCommand A -->>- S: Result<CommitCommand, Err> Note right of A: A dry run is performed
before CommitCommand is executed S ->>+ StoreCommandExecutor: execute(StoreCommands) StoreCommandExecutor -->>- S: Result<(), Err> S -->> c: Result<(), Err> deactivate S end
StoreCommand A -->>- S: Result<PrepareCommand, Err> S ->>+ StoreCommandExecutor: execute(StoreCommands) StoreCommandExecutor -->>- S: Result<(), Err> S -->> c: Result<(), Err> end rect rgb(192, 192, 192) Note right of c: Scribe commits prepared data c ->> S: commit(Scope, StoreCommands) S ->>+ A: get_commit_command() Note right of A: CommitCommand implements
StoreCommand A -->>- S: Result<CommitCommand, Err> Note right of A: A dry run is performed
before CommitCommand is executed S ->>+ StoreCommandExecutor: execute(StoreCommands) StoreCommandExecutor -->>- S: Result<(), Err> S -->> c: Result<(), Err> deactivate S end
