How to stop NodeRED from inside a flow?

General
1

I need to run NodeRED in batch mode (headless) in a Docker container. Works perfect but I cannot terminate NodeRED anymore.

NodeRED ist started (as root) with

/usr/local/bin/node $NODE_OPTIONS node_modules/node-red/red.js --userDir /data $FLOWS &

I tried to kill NodeRED with the exec-Node and SIGTERM / SIGKILL. But this does not work.

How can the entire NodeRED process be stopped from a flow?

2

I don't know anything about docker - heard of it, but that's about it.

Sorry, but why do you need to STOP node-red?

But if you want to stop Node-Red, why not issue the command:

node-red-stop?
With suitable path in front of it.

3

I have a flow running and at the end of this flow NodeRED has to terminate by itself. There should not be any further command as node-red-stop to be performed from outside NodeRED

4

exec node at the end of things happening in the flow.

That enters the command and kills (more like stops) Node-red.

5

No, the exec node does not work. The parameters for the exec node are:

msg.kill="SIGKILL";
msg.pid=global.get("PID");

The global PID is set to the process ID of NodeRED at the beginning of the flow.

6

Well, it maybe doesn't work because it needs the sudo password.

I'm not an expert, but there is a way to get around that.
Then you can simply enter that command and it should work.

But I'm not an expert.

In the exec node you need to put this:
echo myPassword | sudo -S node-red-stop

Where myPassword is your actual password.

It works.

Just tested it.

7

The exec node cannot be used to kill processes it didn't originally spawn itself.

One approach will be to write a script that does the process kill, and then exec that script from Node-RED.

1 Like
8

Just to check though: Could you confirm that the way I said would work?
Sorry again just wanting to make sure what I think is correct.

Of course it would be a lot easier if the node-red-stop command was attributed to not need the password.

9

In this instance, no it would not work because they are running node-red directly, rather than running it as a service (which is what node-red-start/node-red-stop control).

2 Likes
10

Thanks.

Just mentioning then:

AFAIK, my system uses systemd and node-red auto-starts.

I got an exec node and put that trick in with my real password.

Connected an inject node to the exec node, and pressed it.
Node-red stopped.
Well, I got a message at the top of my screen: Lost connection to server.
So I guess it stopped.

[{"id":"260ff9050f0901f0","type":"exec","z":"0918ee609bf69fc7","command":"echo \"my real password\" | sudo -S node-red-stop","addpay":"","append":"","useSpawn":"false","timer":"","winHide":false,"oldrc":false,"name":"","x":470,"y":3660,"wires":[[],[],[]]},{"id":"6f621bb4c69c4357","type":"inject","z":"0918ee609bf69fc7","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":170,"y":3660,"wires":[["260ff9050f0901f0"]]}]
11

I am executing NodeRed as root (so I don't need sudo) and this does not work :frowning:

What is node-red-stop? I cannot find anything about this command. Maybe a RPI system script to start/stop NodeRED. But not available in my Docker environment.

12

Sorry @wolfred .... My reading skills are failing.

This is not my week for getting things right.

13

Solved it. There is a node exit to exlicity stop NodeRED: node-red-contrib-exit (node) - Node-RED.

This works like charm.

1 Like
14

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