Director - dandeliondeathray/gooseberry GitHub Wiki

The Director service is Erik's attempt at the core logic.

Terminology

The Director executes a pipeline.

A pipeline consists of many steps.

A step has an associated work, which it performs.

A step has zero or more dependencies, which are executed before the step.

A step has a result.

A step can be executed.

Work can be scheduled.

Step states

A step is a state machine.

• State: Not executed

  Initial state upon step creation.

• State: Dependencies pending

  Dependencies are being executed, but not all have completed.

• State: Work pending

  Work has begun, but has not completed. All, if any, dependencies have completed.

• State: Completed

  All dependencies have completed, and the work is complete. There is a result.

• Transition: Not executed -- Execute --> Dependencies pending:

  Execute all direct dependencies in parallel.

• Transition: Not executed -- Execute with no dependencies --> Work pending

  Schedule the work.

• Transition: Dependencies pending -- All completede --> Work pending

  All dependencies have completed. Schedule work.

• Transition: Dependencies pending -- At least on failed --> Completed with result.

  At least on dependency failed. Cannot schedule work. Complete with failed result.

• Transition: Work pending -- Work finishes with some result --> Completed with result

  The work has finished, with some result.