Middleware

Warning

This feature is in beta mode and subject to changes. Any feedback is appreciated.

Presentation

Simpleflow allows for the execution of functions before and after the execution of an Activity.

To do this, you may pass functions as paths when running in standalone mode or when launching a worker (worker.start command):

simpleflow standalone
        --domain TestDomain \
        --nb-deciders 1 \
        --nb-workers 1 \
        --middleware-pre-execution module.path.pre.execution.function \
        --middleware-pre-execution module.path.pre.execution.second.function \
        --middleware-post-execution module.path.post.execution.function \
        myWorkflow \
        --input '{"args":[], "kwargs": {"task_list":"test"}}'

The above example will execute two functions before each Activity code, and one after.

The --middleware-pre-execution and --middleware-post-execution arguments are also accepted by the workflow.start command in --standalone mode.

Writing a middleware function

Middleware pre-execution functions receive the activity context. Middleware post-execution functions receive the activity context and result.

def my_pre_execution_func(activity_context, **kwargs):
  pass

def my_post_execution_func(activity_context, result, **kwargs):
  print("activity result:", "result")