Node-RED business flows are applications that represent a process that is executed when a flow is deployed. A flow consists of nodes that can be wired together. The data that is passed along the wires is called messages.

Prerequisites

You need a working cenTaur cluster with the Node-RED manager to access the Node-RED admin console.

Introduction


In cenTaur, Node-RED business flows replace what used to be manual server actions, automatic server actions and hotfolder actions in a censhare Server environment. Node-RED business flows can also be used to replace transformation module assets.

Node-RED business flows can be used in any context and for many purposes in a cenTaur cluster. Business flows provide a greater flexibility to customize a cenTaur cluster.

Flow (tab) vs. flow (wired nodes)

You create flows in the Node-RED admin console. Each flow is represented in a tab. As you can see in the flow diagrams below, a flow can consist of a set of nodes that are all wired (with or without splits) or of multiple sets of wired nodes.

%%{init: {'theme':'default'}}%% graph LR A(Node 1) --- B(Node 2) --- C(Node 3)
%%{init: {'theme':'default'}}%% graph LR A(Node 1) --- B(Node 2) --- C(Node 3) B(Node 2) --- E(Node 4) --- F(Node 5)
%%{init: {'theme':'default'}}%% graph LR A(Node 1) --- B(Node 2) --- C(Node 3) D(Node 4) --- E(Node 5) --- F(Node 6)

The term flow is used for both occurrences - all nodes on a tab and a set of wired nodes - without clear distinction. In our documentation, we refer to flows for all nodes on a tab.

The flow data model shows that even nodes that are not wired but are placed on the same tab are connected because the nodes all have a z reference to the tab that acts as the root element:

%%{init: {'theme':'default'}}%% graph LR    A(Node 1) --- B(Node 2) --- C(Node 3) D(Node 4) --- E(Node 5) --- F(Node 6) T(Tab) -.- A(Node 1) T(Tab) -.- B(Node 2) T(Tab) -.- C(Node 3) T(Tab) -.- D(Node 4) T(Tab) -.- E(Node 5) T(Tab) -.- F(Node 6)

Create custom flows

All Node-RED business flows are stored in a single JSON file (flows.json). The flows.json file is part of the installation of cenTaur. When you start cenTaur, the flows.json file is deployed in the Node-RED microservice.

To customize and create your own Node-RED flows, cenTaur comes with a Node-RED admin instance that can be launched from the Node-RED manager. The Node-RED manager also serves to merge and deploy your custom flows to your production instance of cenTaur.