async system tasks documentation?

[Jiehong]

Hi,

SystemTasks can be async or not (default):

conductor/core/src/main/java/com/netflix/conductor/core/execution/tasks/WorkflowSystemTask.java

Line 63 in 38379b8

public boolean isAsync() {

However, the way they are handled is not entirely clear to me, and I couldn't find any doc per say.

This is what I've got so far, but correct me if I'm wrong:

Async = false, system tasks only

Conductor will decide if the task must start or not based on a previous action.
Ex: start a workflow -> first system task is created and start is called.
Ex: task M is updated by a worker -> task N is scheduled by conductor, and start is called.

Async = true, system tasks only

Conductor defers things to a queue.

If the system task is the only one in the workflow:

1. workflow started
2. conductor put the system tasks in an internal queue (

   conductor/core/src/main/java/com/netflix/conductor/core/execution/WorkflowExecutor.java

   Line 1505 in 586dc3e

   tasksToBeQueued.add(task);

   )
3. Later (when?), depending on the status of the tasks, start or execute is called (

   conductor/core/src/main/java/com/netflix/conductor/core/execution/AsyncSystemTaskExecutor.java

   Line 116 in 586dc3e

   boolean isTaskAsyncComplete = systemTask.isAsyncComplete(task);

   )
4. if the task is not isAsyncComplete, it gets re execute after workflow.system.task.worker.callback.seconds.

Is that correct?

Also, is there a timeout each time a system task's start or execute method is called?

[kishorebanala]

@Jiehong Your understanding is correct.

Also, is there a timeout each time a system task's start or execute method is called?

There are no blanket timeouts for System task execution, but task specific timeouts still apply.

[Jiehong]

thanks!