问题:

There many workflow system out there but I was wondering which one of the open source workflow management system is the closest to the AWS Flow Framework (with Amazon SWF like capability build in)?

回答1:

AWS Flow Framework itself is open source under Apache 2.0 license. Its source code is available on github: https://github.com/aws/aws-swf-flow-library.

Update: At 2017 Uber released Cadence which is an open source version of SWF service and associated client side libraries.

回答2:

Amazon SWF is quite different from the other existing workflow systems :

It is not trying to implement BPMN (we could say it is lower level than most workflow systems)
It is focused on distributing tasks to heterogeneous systems (so you can run the activities on any platform, in any language.)

Besides the official Java Flow Framework, I only know :

Gordon (Ruby), but I'm not sure it's open-sourced yet
aws-swf-toolkit (Javascript/Node.js) (disclaimer: I'm the author of this one)

回答3:

(Shameless post?) I started writing my own library (SimpleWorkflowFramework.NET) for use in C# and its available at https://github.com/sdebnath/SimpleWorkflowFramework.NET. It definitely could use some help if anyone is interested.