(Not a) Bug in Inject node?

Core Development
1

I see this with Node-red v3.1.9, node.js 18.20.2, also with node.js 20, on a Raspberry Pi Zero Two.
Inject nodes are set to fire after a range of short delays.
It appears that they do fire (the delayed message is eventually delivered) but messages triggered less than about 8 seconds after startup don't get passed to a debug node, nor is other downstream processing triggered. (But notice that the delay node is triggered,)

First image: DEPLOY. All of these inject nodes are new, so at deploy, they all fire.

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image1121Ă—707 69.1 KB

Second image: Reboot Pi and wait for Node-red to start.

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image1236Ă—714 58.5 KB

Only the Inject after 10 sec shows up, though the 10 sec delay node does get triggered.
If I restart Node-red rather than rebooting, more debug messages show up, but not the 0.1sec initial delay.

What's going on?

[{"id":"fdc7b9edf9fb44f9","type":"inject","z":"7f20ad1a9174e987","name":"","props":[{"p":"payload"}],"repeat":"","crontab":"","once":true,"onceDelay":"2","topic":"","payload":"Inject after 2 sec","payloadType":"str","x":450,"y":760,"wires":[["f7d5fe126bb47c28"]]},{"id":"9be553d0d36b0efe","type":"inject","z":"7f20ad1a9174e987","name":"","props":[{"p":"payload"}],"repeat":"","crontab":"","once":true,"onceDelay":"4","topic":"","payload":"Inject after 4 sec","payloadType":"str","x":450,"y":800,"wires":[["f7d5fe126bb47c28"]]},{"id":"12a325d5b82a3106","type":"inject","z":"7f20ad1a9174e987","name":"","props":[{"p":"payload"}],"repeat":"","crontab":"","once":true,"onceDelay":"5","topic":"","payload":"Inject after 5 sec","payloadType":"str","x":450,"y":840,"wires":[["f7d5fe126bb47c28"]]},{"id":"f88bb54c44b1f92d","type":"inject","z":"7f20ad1a9174e987","name":"","props":[{"p":"payload"}],"repeat":"","crontab":"","once":true,"onceDelay":"6","topic":"","payload":"Inject after 6 sec","payloadType":"str","x":450,"y":880,"wires":[["f7d5fe126bb47c28"]]},{"id":"70004a8e73766c05","type":"inject","z":"7f20ad1a9174e987","name":"","props":[{"p":"payload"}],"repeat":"","crontab":"","once":true,"onceDelay":"10","topic":"","payload":"Inject after 10 sec","payloadType":"str","x":450,"y":920,"wires":[["f7d5fe126bb47c28"]]},{"id":"f7d5fe126bb47c28","type":"debug","z":"7f20ad1a9174e987","name":"debug 18","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":700,"y":880,"wires":[]},{"id":"a3c9889370fe5712","type":"inject","z":"7f20ad1a9174e987","name":"","props":[{"p":"payload"}],"repeat":"","crontab":"","once":true,"onceDelay":"0.1","topic":"","payload":"Inject after 0.1 sec","payloadType":"str","x":450,"y":720,"wires":[["31492ac2a39a7fb7","f7d5fe126bb47c28"]]},{"id":"31492ac2a39a7fb7","type":"delay","z":"7f20ad1a9174e987","name":"","pauseType":"delay","timeout":"10","timeoutUnits":"seconds","rate":"1","nbRateUnits":"1","rateUnits":"second","randomFirst":"1","randomLast":"5","randomUnits":"seconds","drop":false,"allowrate":false,"outputs":1,"x":700,"y":720,"wires":[["662e0868576770ea"]]},{"id":"662e0868576770ea","type":"change","z":"7f20ad1a9174e987","name":"payload = Delayed 10 sec","rules":[{"t":"set","p":"payload","pt":"msg","to":"Delayed 10 sec","tot":"str"}],"action":"","property":"","from":"","to":"","reg":false,"x":730,"y":780,"wires":[["f7d5fe126bb47c28"]]}]
2

This may well be that the browser has not yet connected to the server when the inject is happening.

3

Yes that makes sense.

I'm not sure if "Inject after 0.1 second" is 0.1 second after Node-red starts up or 0.1 sec after a browser connects to it.

4

It is after node-red starts. There may be no browser connected when node-red starts up, or there could be 10 browsers connected.

5

You can confirm exactly what is happening by ticking the 'log to system console' option in the Debug node; you'll see all of the expected messages in the node-red console log without the need for an editor to be open and connected.

6

Ah yes, if only I'd mastered accessing the system log in RPIOS Bookworm!

But it's the activity in the editor that I need to make reliable since I'm trying to reload the page after rebooting the Pi.

I can inject after 10 seconds, just hoping that's a long enough delay.
Or does Node-red know when the first browser connection occurs?

7

Or does Node-red know when the first browser connection occurs?

Node-RED does, but that isn't exposed to nodes - flows typically don't care about the editor and whether anything is connected, so it isn't something we cater for

1 Like
8

If you start node-red using
node-red-start
then the log will be displayed for you.

9

On Linux, sudo journalctl -u node-red -f -n 500 -o cat --no-hostname should show you the log.

10

Thank you both :grinning:

11

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