🧱 Virtual Process Flow queue for Node-RED

Description

Manage persistent FIFO queues for industrial process flows using Node-RED.
With full MQTT support, file persistence, and dashboard integration.

** For pedagogical purposes only. Commercial or industrial use is not recommended. **

• NPM Repository: npmjs @uopoc/node-red-processstack
• GIT Repository: github @uopoc/node-red-processstack
• RED Node: Node-Red @uopoc/node-red-processstack

** WARNING ** :

• Minimum Node-RED Version 4.0.0+
• Minimum NodeJS Version 18.0.0+
• Minimum node-red-dashboard Version 3.6.0+

Copyright © 2025, Université d'Orléans
Licensed under the MIT License – See LICENCE file included with this package

🧰 Main Features

• Persistent FIFO (First-In First-Out) queues (stacks)
• MQTT commands & events Optional
• dashboard UI ready using a specific node
• Structured by Process / Cell / Queue

🔧 Available Nodes

| Node | Description | |--------------|-------------| | pst-push | Adds an item to the queue | | pst-shift | Removes the first item from the queue | | pst-transfert | Moves an item from a source queue to a target queue | | pst-peek | Same as shift but without removing item | | pst-supervisor | Returns the entire queue contents | | pst-clearstack | Empties the queue completely | | ui-pst-table | in Dashboard panel: display the content of the queue in the dashboard |

🛠️ Configuration Nodes

| Node | Description | |-----------------------------------|-----------------------------------| | pst-stack (config) | Defines a persistent FIFO queue | | pst-manufacturingcell (config) | Defines a production cell | | pst-processflow (config) | Defines a production line |

💾 Persistence

Each queue is automatically saved to disk after every modification:
/data/pststacks///.json

Installation

npm install @uopoc/node-red-processstack

ChangeLog

Voir le changelog

Nodes details

PUSH Node

Add (push) an item to the FIFO queue

• Input: Object with :
  • id Required, string or number (max 128 chars). Allowed characters: a-z, A-Z, 0-9, _, -,
  • userdata : Required, must be an object with any metadata you want to store (can be empty object) Rm: msg.payload can also be an item provided by the pull node
    Exemple:
    msg.payload = {
    "id": "ITEM-001",
    "userdata": { "batch": "B001", "weight": 2.5 }
    }
• Output: Object with : msg.payload = true/false
  msg.item = {
  _itemid: uniqueid (UID),
  _created: creation timestamp (ms from 1970),
  _updated: last update timestamp,
  id: id providen in the input,
  userdata: userdata provided at the Input
  msg.error = {
  code,
  string
  }
  msg.stackdata:{
  processid,
  processname,
  company,
  department,
  location,
  cellid,
  cellname,
  manufacturer,
  model,
  stackid,
  stackname
  }

SHIFT Node

Remove (shift) an item from the FIFO queue

• input: Dummy message to triger the node
• output: (same as peek or msg.item provided by the output of push node)

PEEK Node

Get (whithout shift) an item from the FIFO queue

• input: Dummy message to triger the node
• output: (same as shift or msg.item provided by the output of push node)

TRANSFERT Node

Transfert (pull/push) an item from a queue to another

CLEAR Node

Delete all items from the FIFO queue

SUPERVISOR Node

Get items list from the FIFO queue. \ Check the autoupdate checkbox in the node property in order to update the status every queue change.\ use the ui-pst-table or a ui-template node in order to display the queue in a dashboard.

UI-PST-TABLE Node

In Dashboard panel: display the content of the queue in the dashboard\ Should be connected to the second output of the supervisor node.\ It can replace a ui-template node

MQTT

You can connect the queue config node to a mqttClient and provide 3 topics:

• Command: (not implemented) Input command (push, shift, clear, peek)
• Events: Every event (push, shift, clear, etc.) will emit message
• Superv: Emits complete queue state and profile after event

Superv

Please configure the topic and the mqtt client in the queue config Node after each operation, a mqtt message is send to the specified topic:
Content:

• path: (string) processid/stackid,
• profil: {...},
• stack: [item1,...]
• count: Number of item in the queue
• length: Maximum number of item in the queue

Events

Please configure the topic and the mqtt client in the queue config Node
after each operation, a mqtt message is send to the specified topic:
Content:

• path: (string) processid/stackid,
• event: (string) type of activity (push, shift, clear...)
• item: (object) item
• count: (number) Number of item in the queue
• length: (number) Maximum number of item in the queue

Command

Not Implemented Yet

About Us

• Company: Université d'Orléans – France
• Department: Polytech Orléans (Engineering School of the University of Orléans)
• Specialization: Industrial Engineering applied to cosmetics, pharmaceuticals, and food industries Learn more about our program
• Facility: Teaching Factory – Polyfactory