allowski / crazy-frog-bpmn

Crazy Frog BPMN

A lightweight implementation of a BPMN using Node.js.

Description

Crazy From BPMN is meant to be a cloud-based solution running completely serverless and designed to make use of tools such as Cloud Functions, Serverless Databases and Distributed computing.

Concepts

Flow

A flow consists on a single flow file which specifies the tasks to be done and also de diagram to coordinate and choreograph all the tasks to make them run.

Task

A task is an atomic process piece that needs to run at some point. For instance the every flow must start with a Entrypoint task.

Process

Each time a Flow gets started, a new Process instance is started to track all the context and as a reference point to understand where the state is at.

Executors

An executor is a piece of code that given an input will output as result. We have on the project the following executors:

• Entrypoint
• Conditional
• Http Request
• User Form
• Endpoint

REST API

This is a preview of the desired Rest API interface.

Flow API

POST /flows

Creates a new flow

GET /flows/:id

Gets a new flow by its ID.

DELETE /flows/:id

Delete a flow by its ID.

Process API

POST /process

Starts a new process for the given flow.

GET /process/:id

Gets the current process data.

DELETE /process/:id

Delete a process by its ID

Design Considerations

The idea is to have a BPMN with nice features that will allow to conduct a flow and keep a track of every aspect of the running processes at a given time.

Dev Key Features

• Serverless.
• Process Tree.
• Distributed computing.
• Async processing.
• Immutable database.

User Key Features

• Easy-to-use BPMN functions.
• High state visibility.
• Customizable behavior.
• Realtime notifications.
• Web-based UI.

Why not just use Camunda or other solutions?

There are multiple pitfalls where camunda is short for a solution:

• JVM is heavy on memory.
• Scaling is hard (Sharding, Distributing and Horizontal-scaling).
• Monitoring poses a challenge even for most experienced admins.
• Lack of out-of-the-box connectors (I.e SQS, Kafka, RabbitMQ, etc.).
• Camunda is not SaaS friendly and basically forces you to use their solutions if you need more (Freemium-like behavior).