Workflow Execution: Major Actors

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Major Actor Hierarchy

At the highest level, these are the main actors involved in workflow execution.

Actors and their Purposes

WorkflowManagerActor

The WorkflowManagerActor is responsible for:

• Polling the WorkflowStore at pre-configured intervals.
• Starting new workflows
• Tracking, supervising and aborting running workflows
• Parent actor for all WorkflowActors

WorkflowActor(s)

The WorkflowActor is responsible for:

• Co-ordinating the stages of a workflow lifecycle from parsing through to finalization.
• Parent actor of the WorkflowExecutionActor which runs the workflow's jobs.

WorkflowExecutionActor(s)

The WorkflowExecutionActor is responsible for:

• Starting jobs and sub-workflows as soon as they are able to run.
  • Based on values in the (in-memory) ValueStore and ExecutionStore objects.
• Parent actor for all EngineJobExecutionActors and SubWorkflowExecutionActors.

EngineJobExecutionActor(s)

Each EngineJobExecutionActor (EJEA) is responsible for:

• Running a single job.
  • A "job" is a command line instruction to run on a backend.
  • Multiple shards for a single call each get their own EJEA.
  • Multiple attempts to run the same job operate within the same EJEA
• Respects hog-limiting
• Checks the call cache and job store to avoid running the job if it doesn't have to.
• Triggers job initialization, execution and finalization at appropriate times.

SubWorkflowExecutionActor(s)

Each SubWorkflowExecutionActor is responsible for:

• Running a single sub-workflow.
• Parent actor for a new WorkflowExecutionActor (see above) created to run the sub-workflow.

Major Actor Hierarchy (in context)

The above diagram omitted a lot of details. This diagram attempts to show a little more of the context:

See Also

• EngineJobExecutionActor (TODO)
• Backend Execution Actors (TODO)