oe-node-red

Table of Contents

• Introduction
• About the module
• How to add Node-RED feature in oe-cloud -based app
  • Configuration
    • server/config.json settings
    • server/node-red-settings.js
    • Notes
• Migration from oe-cloud v 1.2.0/1.3.0/1.4.0

Introduction

Node-RED has been a feature of oe-cloud framework for some time now, and it has been widely adopted for its extreme ease of use. In order to take advantage of new features introduced in newer versions of Node-RED, we need to be able to upgrade Node-RED easily and seamlessly. To this end, Node-RED has been separated from the core oe-cloud framework and the Node-RED integration is now implemented as an optional "app-list" module for the oe-cloud-based app. This new module is called oe-node-red.

About the module

oe-node-red is a nodejs module for Node-RED integration with oe-Cloud, and this module is the only dependency required by an oe-Cloud based application to get the Node-RED feature.

This module adds a loopback boot-script for starting Node-RED as part of the loopback app boot-up. It also adds a few loopback models to the app for managing Node-RED data.

The oe-node-red module also manages other dependencies like oe-node-red-nodes, and Node-RED itself. As of now, the Node-RED dependency version is changed from 16.x to 18.x, which has various improvements over its predecessors.

Note:

Unlike previous iterations of Node-RED integration in oe-Cloud, now Node-RED flows are saved to database irrespective of whether the app is in production mode or not. Flows are also saved to {userDir}/{flowFile} in parallel. This is to enable source-control of flow data, as well as to aid initial data seeding in production.

How to add Node-RED feature in oe-cloud -based app?

To get the Node-RED feature in the application, the oe-node-red node module needs to be added as a package.json dependency in the application.

Also, the module needs be added to the server/app-list.json file in the app.

For e.g.,

package.json  (only part of the file is shown here, with relevant section in bold):


   ...
   ...
   "dependencies": {
       ...
       ...
       ...
       "oe-node-red": "git+https://github.com/EdgeVerve/oe-node-red.git#2.0.0",
       ...
       ...

server/app-list.json   (Relevant section in bold):

[
    {
        "path": "oe-cloud",
        "enabled": true
    },
    {
        "path": "oe-node-red",
        "enabled": true
    },
	. . .
	. . .
]

Configuration

The oe-node-red module is configured from two files -

• server/config.json
• server/node-red-settings.js

server/config.json settings

The oe-node-red configuration settings in the application's config.json are used for high level control, like enabling/disabling Node-RED, enabling and setting up Node-RED-admin roles, etc.,

All oe-node-red configuration parameters in this file are optional.

The following are the oe-node-red configuration settings possible in the application's server/config.json file:

setting type default (if not defined) Description

disableNodered boolean false Use this to turn off Node-RED (despite having the oe-node-red module) by setting this parameter to true. Default is false, i.e., Node-RED is enabled by default. See notes below for corresponding environment variable.

enableNodeRedAdminRole boolean false Use this to allow only users having certain roles to access the Node-RED UI by setting this parameter to true. Default is false, which allows all users access to Node-RED UI.

nodeRedAdminRoles string array ["NODE_RED_ADMIN"] Use this to setup the names of the roles which have access to the Node-RED UI. This setting is used only if enableNodeRedAdminRole is true.

---

server/node-red-settings.js

The application's server/node-red-settings.js supports the same parameter settings as Node-RED's settings.js file.

If this file is present, parameters from this file are merged and prioritized over the sane default values mentioned below and the result is taken as Node-RED configuration

Thus, this file can be used to override the Node-RED configuration defaults provided in code

Some of the important settings possible in this file are documented here: https://nodered.org/docs/configuration

A sample server/node-red-settings.js file is provided below:

module.exports = {                                  // All defaults mentioned below are applicable only
                                                    // if this file (server/node-red-settings.js) is **not present**
 
  httpRequestTimeout: 120000,                       // default: not set
  httpAdminRoot: '/red',                            // default: /red
  httpNodeRoot: '/redapi',                          // default: /redapi
  userDir: 'nodered/',                              // default: nodered/
  nodesDir: '../nodes',                             // default: ../nodes
  flowFile: 'node-red-flows.json',                  // default: 'node-red-flows.json'
  flowFilePretty: true,                             // default: true
  functionGlobalContext: {                          // default: {
    loopback: require('loopback'),                  //            loopback: require('loopback'),
    logger: require('oe-logger')('node-red-flow')   //            logger: require('oe-logger')('node-red-flow')
  }                                                 //          }
}
 

This file (server/node-red-settings.js) in the application is optional. In its absence, sane defaults as mentioned above are provided by the oe-node-red module.

Notes

As mentioned above, Node-RED integration can be disabled from the server/config.json. It can also be disabled by setting the environment variable:

DISABLE_NODE_RED=true   (or 1)

If server/node-red-settings.js is not present, the defaults that are provided are as in the comments above.

As noted earlier, Node-Red flows are saved to database whether the app is in production mode or not. A flow data file is also persisted to {userDir}/{flowFile}. If production mode is enabled by setting the environment variable NODE_ENV to production, then the flows won't be persisted to file. Thus, flows would only be saved to database in production.

During development, the flow data file persisted at {userDir}/{flowFile} contains data in the same format as the database table holding flows (NodeRedFlow table). So this file can be used directly for initial seeding of data in production.

Migration from oe-cloud v 1.2.0/1.3.0/1.4.0

In this new implementation of Node-RED integration, flow-nodes are now stored as separate records, one record per node. A record of a node looks like this:

{
    "id"   :    "7b279bd6.7b9064",
    "node" :    {
                    "id" : "7b279bd6.7b9064",
                    "type" : "mqtt in",
                    "z" : "8a31d1.1fd8ce3",
                    "name" : "",
                    "topic" : "testtopic",
                    "qos" : "2",
                    "broker" : "5e5886e3.30a7d8",
                    "x" : 190,
                    "y" : 160,
                    "wires" : [ [ ] ]
                }
}

So, a flow that contains 10 nodes would be stored as 10 records plus an extra node of type "tab", making a total of 11 records in the database (Any configuration nodes will add more nodes). This is in contrast to the earlier (oe-cloud v 1.2.0/1.3.0/1.4.0) implementation where all flows (and their nodes) were stored as a single record in the database. The old storage format will not work with the new Node-RED integration implementation.

To address this, the following migration strategy can be adopted:

1. Before upgrading to the new oe-Cloud that includes the new Node-RED integration implementation, Login to your application with the old Node-RED implementation and open the Node-RED UI.
2. Select a tab, Do "Select All" using "Ctrl+A", and export the current tab's flows to the clipboard using the Menu --> Export --> Clipboard option.
3. Save the contents of the clipboard to a local file, using a filename which is the same as the tab name.
4. Repeat steps 2 and 3 for all tabs in your Node-RED interface, at the end of which you should have as many local files as there are tabs in your Node-RED UI.
5. Delete all your Node-RED flow-data from the NodeRedFlow table in the application database.
6. Upgrade to the latest version of oe-cloud which includes the new implementation of Node-RED integration (Follow instructions from How to add Node-RED feature in oe-cloud -based app? section above).
7. Login to your application and open the new Node-RED UI
8. Import the flows from each of the files created in step 3 back into Node-RED, naming the tabs the same as the filename, using the Menu --> Import --> Clipboard option
9. Run a sanity test on your flows.
10. Optional: At the end of the import, you should have a {userDir}/{flowFile} file containing all flow data as an array of nodes. Use this file to commit to source-control and for initial data seeding in production environment.