ElixirFBP

This repository will contain an implementation of Flow-based Programming in the Elixir language. For more on FBP, see Wikipedia, J. Paul Morrison, and NoFlo

This implementation is discussed here.

Description

This Elixir implementation of an FBP system is influenced by the FBP Protocol as described at the NoFlo website. These modules, however, can be used without regard to any particular runtime by using the Network and Graph modules directly.

Note that an earlier release of this repository contained a runtime implementation that communicated, via websockets, with a noflo-ui client. The client could be running locally or remotely, using the on-line version at app.flowhub.io. This code was refactored out and will appear in another repository.

Architecture

ElixirFBP is made up of the following Elixir modules:

• ElixirFBP.Network
• ElixirFBP.Graph
• ElixirFBP.Subscription

The first two modules are implemented as Elixir GenServers

ElixirFBP.Network keeps track of the FBP network that is currently being built and/or run. It knows how to handle FBP protocol network commands.

ElixirFBP.Graph keeps track of the FBP graph that is currently being built and/or run. It knows how to handle FBP protocol graph commands.

An ElixirFBP.Subscription serves as connection between any two components, hence there is one Subscription per FBP graph edge. The components correspond to the publisher and subscriber in the Reactive Stream protocol. A Subscription can limit the number of Information Packets that can be sent from a publisher to a subscriber, that is, "back pressure" can be applied to the publisher.

Limitations

• The components for this runtime are hard-wired in ElixirFBP. A "discovery" mechanism to locate Elixir components will be implemented in a future release.