tedge-nodered-plugin

Pre-requisites

Naturally, node-red must be installed in order to use this plugin as the plugin uses the node-red REST api to managed node-red flows. We recommend installing node-red in a container using the tedge-container-plugin-ng thin-edge.io software management plugin.

node-red supports two different modes, one is the classic mode when flows are just simple json files (e.g. flows.json), and the other is the project mode where a flows.json is deployed via a git repository. The former (simple json files) is more flexible and widely used, so it is the recommended way to deploy flows to a device.

To help with the installation the following docker-compose.yaml files can be used to deploy a node-red container via thin-edge.io.

• node-red (flows/classic mode)) (recommended)
• node-red in project mode)

Be sure to check out the Node-RED documentation for more details on how to configure the node-red container.

Plugin summary

Install/remove node-red flows or projects on a device using the thin-edge.io software management plugin API.

Technical summary

The following details the technical aspects of the plugin to get an idea what systems it supports.

Languages	golang
CPU Architectures	armv6 (armhf), armv7 (armhf), arm64 (aarch64), amd64 (x86_64)
Supported init systems	N/A
Required Dependencies	-
Optional Dependencies (feature specific)	-

How to do I get it?

The following linux package formats are provided on the releases page and also in the tedge-community repository:

Operating System	Repository link
Debian/Raspbian (deb)
Alpine Linux (apk)
RHEL/CentOS/Fedora (rpm)

What will be deployed to the device?

• The following software management plugins which is called when installing and removing nodered projects via Cumulocity IoT
  • nodered-project - Deploy a project using the node-red project structure (e.g. git repository containing a flow)
  • nodered-flows - Deploy a node-red flow (e.g. flows.json)

Plugin Dependencies

The following packages are required to use the plugin:

• node-red (we recommend deploying it as a container)

Deploying format

nodered-flows

A node-red flows file, is the classic node-red json format which you get when you export the node-red project from the node-red UI.

Example flows:

• flows.json

You can use go-c8y-cli to create the Cumulocity IoT software repository items for your flow:

# Create a new software item
c8y software create --name myflow --softwareType nodered-flows

# For each version, upload a new flows.json file
wget -O - https://github.com/reubenmiller/nodered-demo-next/blob/main/flows.json > flows.json
c8y software versions create --software myflow --version 1.0.0 --file ./flows.json

nodered-project

A node-red project can be deployed to a device via the software management feature, where the software artifact is a simple json format which the .repo property which indicates the Git repository of the node-red project which should be deployed to the device.

Below is an example of such as deployment artifact.

{
    "repo": "https://github.com/reubenmiller/nodered-demo-next"
}

You can use go-c8y-cli to create the Cumulocity IoT software repository items for your flow:

# Create a new software item
c8y software create --name my-nodered-project --softwareType nodered-project

# For each version, upload a new flows.json file
echo '{"repo": "https://github.com/reubenmiller/nodered-demo-next"}' > my-nodered-project.json
c8y software versions create --software my-nodered-project --version 1.0.0 --file ./my-nodered-project.json

Configuration

The tedge-nodered-plugin interacts with node-red via its API endpoint, which is by default http://127.0.0.1:1880. If you are using a custom node-red installation and have changed the port, then you can add the following configuration file (which can also be managed by thin-edge.io via the tedge-configuration-plugin), where you can control the node-red API endpoint which is used by tedge-nodered-plugin.

Below shows an example of changing the default API endpoint to http://127.0.0.1:1881:

File: /etc/tedge/plugins/tedge-nodered-plugin.toml

[nodered]
api = "http://127.0.0.1:1881"

Note: The configuration is read each time the software management plugin is called, so there is no need to restart any services after changing the configuration.