Flowex - Flow-Based Programming framework

I’m curious, if there can only be one error_pipe :error_handler and its order does not matter, why not add it as an option to use Flowex.Pipeline like use Flowex.Pipeline error_pipe: :error_handler or even as a full argument to make it more explicit?

Cool design overall!

Hi @OvermindDL1
“Physically” error_pipe is always the last pipe in a pipeline. And components are ordered in the way you define them, so it is natural to place error_pipe after all defined pipes.

True, but conceptually it is a side path that everything takes another path to if they error, but is skipped if not.

Hi, Anton,

I am new to Elixir and Flowex. I am trying to find a usage of Flowex for a project, but I have a question.

I created a pipeline as below.

defmodule Helios.Pipeline.Delete do
use Flowex.Pipeline

pipe Helios.Flow.DeleteAsset, count: 1
pipe Helios.Flow.Finalize, count: 1
end

Also, as you guided, I connect the pipeline to superviser (strategy: :one_for_one).

pipeline_delete = Helios.Pipeline.Delete.supervised_start(supervisor_pid)

The pipeline is up and running OK. For curious, I killed the pipeline process, but I can see only Producer process is back, but not the others. Is it what you expected or do I miss any?

Below screen shots are before and after killing the pipeline from :observer.
Red lined Flows are what I created and the other processes are created by Flowex pipeline.

Before

pipeline-before-kill.jpg697×180 30.6 KB

Thank you for advance.
KIM.

Since I am a new user, I can post only one image. So below is after screen shot.

After

Hi @ikim
Seems like you kill the supervisor of the pipeline. This is very unexpected case. Current implemetation start supervisor with producer only and then adds stages one by one and subscribe to each other. So it will fail to restart all the stages after supervisor crash.
But I think this can be changed. May I ask you to create an issue with the example?
Thanks!

Thank you @antonmi
I created an issue in the github.

@ikim
I’ve changed starting strategy for pipeline.
Please, try the new 0.5.2 version of the library.

@antonmi

Yes, it works as I expected. I appreciate your quick help!!!

ikim.

You are welcome!
Thank you for the issue which makes Flowex better!