GreaterThan, LLC

This release introduces Filter Events, and Pipeline Actions.

These events are raised by the Filter object:

• start
• exit
• end

They can be handled by attaching a callable to each event. The start and end events are raised automatically, but the exit event is triggered by setting the action in the event handler to either EXIT, or SKIP.

Like this:

from pipelayer import Filter, FilterEventArgs, Pipeline, Action
from pipelayer.filter import raise_events

class MyFilter(Filter):
    @raise_events                # Raises the events
    def run(self, data, context):
        return f"{data}has been changed"

# Handles the filter start event
def my_filter_start(obj: Filter, args: FilterEventArgs):
    args.data = "Filter Skipped"
    args.action = Action.SKIP    # This will skip over the step

my_filter = MyFilter()
my_filter.start.append(my_filter_start)

my_pipeline = Pipeline(steps=[
    my_filter
])

output = my_pipeline.run("Some data...", None)

#  output is "Filter Skipped"