Execution State Machine


This docs site is currently under construction although this github README below should suffice for now.


In Julep, an Execution represents an instance of a Task that has been started with some input. The Execution follows a specific state machine model, ensuring consistent and predictable behavior throughout its lifecycle.

Execution States

An Execution can be in one of the following states:

  1. queued: The execution is waiting to start

  2. starting: The execution is in the process of starting

  3. running: The execution is actively running

  4. awaiting_input: The execution is suspended and waiting for input to resume

  5. succeeded: The execution has completed successfully

  6. failed: The execution has failed

  7. cancelled: The execution has been cancelled by the user

State Transitions

The valid transitions between execution states are as follows:

  • queuedstarting

  • startingrunning, awaiting_input, cancelled, succeeded, failed

  • runningrunning, awaiting_input, cancelled, succeeded, failed

  • awaiting_inputrunning, cancelled

  • cancelled, succeeded, failed → (terminal states, no further transitions)

Transition Types

Executions can go through various transition types:

  • init: Initializes the execution

  • init_branch: Starts a new branch in the execution

  • finish: Completes the execution successfully

  • finish_branch: Completes a branch in the execution

  • wait: Pauses the execution, waiting for input

  • resume: Resumes a paused execution

  • error: Indicates an error occurred

  • step: Represents a step in the execution process

  • cancelled: Indicates the execution was cancelled

State Machine Diagram

stateDiagram-v2
    [*] --> queued
    queued --> starting
    queued --> cancelled
    starting --> cancelled
    starting --> failed
    starting --> running
    running --> running
    running --> awaiting_input
    running --> cancelled
    running --> failed
    running --> succeeded
    awaiting_input --> running
    awaiting_input --> cancelled
    
    %% Added transitions for branching
    running --> init_branch : init_branch
    init_branch --> waiting : wait
    init_branch --> cancelled : cancelled
    init_branch --> finish_branch : finish_branch
    finish_branch --> running : resume
    
    %% Updated terminal states
    cancelled --> [*]
    succeeded --> [*]
    failed --> [*]
    finish_branch --> [*]

This state machine ensures that executions in Julep follow a consistent and predictable flow, allowing for complex workflows while maintaining clear status tracking. It provides a robust framework for managing long-running tasks, handling interruptions, and recovering from failures.

Last updated