How to run a Node-RED flow on Home Assistant start

First attempt

Here is an easy and simple way to run a Node-RED flow when Home Assistant starts.

We start in Node-RED with an HTTP node.

Then we edit it to listen to /hastart and choose a name.

This will result in this node which you can insert in your flow and/or create a subflow to use it in multiple flows. Don’t forget to DEPLOY.

Now, in Home Assistant, we create a shell_command and an automation that will run it.

shell_command:
  ha_start: 'curl http://localhost:1880/hastart'
  # http://localhost:1880/endpoint/hastart if you're using the Node-RED Community Hass.io Add-on.

automation:
  - alias: homeassistant_start
    trigger:
      - platform: homeassistant
        event: start
    action:
      - service: shell_command.ha_start

And that’s it. From now on, every time Home Assistant is started the node is triggered.

A better way

I’ve just found a simpler and better way to do that. All we need is a status node and a switch node.

In this case the status node checks for status changes in a selected node. I selected one of my home assistant “events: state” nodes. The switch node checks if the status node is sending the string “node-red:common.status.connected” in msg.status.text.

Following is the JSON code of the sequence. Do not forget to change the status node configuration according to your environment.

[
    {
        "id": "45fc4a1a.70c274",
        "type": "status",
        "z": "152abd73.69dcbb",
        "name": "",
        "scope": [
            "95360a40.8cb83"
        ],
        "x": 100,
        "y": 660,
        "wires": [
            [
                "65572a91.71965c"
            ]
        ]
    },
    {
        "id": "65572a91.71965c",
        "type": "switch",
        "z": "152abd73.69dcbb",
        "name": "",
        "property": "status.text",
        "propertyType": "msg",
        "rules": [
            {
                "t": "eq",
                "v": "node-red:common.status.connected",
                "vt": "str"
            }
        ],
        "checkall": "true",
        "repair": false,
        "outputs": 1,
        "x": 230,
        "y": 660,
        "wires": [
            []
        ]
    }
]

Update - Sep 26, 2020

For those using node-red-contrib-home-assistant-websocket (installed by default in Node-RED Community Hass.io Add-on), here’s another possible solution.

[{
  "id": "b66320a5.f8586",
  "type": "server-events",
  "z": "d0505e55.8a4b8",
  "name": "",
  "event_type": "home_assistant_client",
  "exposeToHomeAssistant": false,
  "haConfig": [{
    "property": "name",
    "value": ""
  }, {
    "property": "icon",
    "value": ""
  }],
  "waitForRunning": true,
  "x": 160,
  "y": 590,
  "wires": [
    ["b46e7e0a.fef1f"]
  ]
}, {
  "id": "b46e7e0a.fef1f",
  "type": "switch",
  "z": "d0505e55.8a4b8",
  "name": "",
  "property": "payload",
  "propertyType": "msg",
  "rules": [{
    "t": "eq",
    "v": "running",
    "vt": "str"
  }],
  "checkall": "true",
  "repair": false,
  "outputs": 1,
  "x": 350,
  "y": 590,
  "wires": [
    []
  ]
}]