Need "correct" version of node-libgpiod ....

sdetweil

@rkorell yes, that is what @electron/rebuild does

recompiles the module (from source) to match

in the magicmirror folder , if not already installed
(my install and upgrade scripts install it for you )

npm install @electron/rebuild

then in the module folder do

../../node_modules/.bin/electron-rebuild

a module needing this should have a postinstall script in package.json to invoke this command

rkorell

@sdetweil Dear Sam,
thanks for this information.
Can you please enlighten me?
I can read what you wrote and I got a light idea - but didn’t understand …

I definitely have used your install script.
what is @electron and
what correlation is between node-libgpiod and @electron ? and what will this

../../node_modules/.bin/electron-rebuild

do?

Sorry for these questions - I would like to understand, what happens.

If this is “neccessary” I will try to automate this for others with a postinstall script.
Thanks for your effort!
warmest regards,
Ralf

sdetweil

@rkorell javascript is compiled to a byteform by the nodejs engine

there is one embedded inside electron and one outside,
nodejs

the bytecode has a version number.
the engine needs the proper version to execute it
like version 21 added a new instruction, but vers 20 engine cant execute it

i dont know the version differences

anyhow, the electron-rebuild application will rebuild the parts of the js code used in the node_helper to match the internal/embedded node engine inside electron

because startup is using the electron app

in server mode we use the mode app

you should know if you run
node serveronly, then the bytecode has to match the nodejs standalone engine version
this is why we try to keep the nodejs/electron internal node versions the same
(there is a node rebuild too)

sdetweil

@rkorell here is the postinstall i provide for a couple modules

#!/bin/bash

base=~/MagicMirror
logfile=/dev/null
if [ ! -e $base/node_modules/@electron/rebuild ];  then 
    cd $base
    if [ -e $base/node_modules/.bin/electron-rebuild ]; then 
	# remove the old version	  
      npm uninstall electron-rebuild >>$logfile 2>&1
    fi	  
    # install the new version 
    npm install @electron/rebuild >>$logfile 2>&1
    cd - >/dev/null
fi

$base/node_modules/.bin/electron-rebuild

they changed the name of the npm package

but as i install it as part of install/upgrade
its correct most of the time

and in package.json, in the scripts section add

"postinstall":"./postinstall"

rkorell

@sdetweil said

you should know if you run
node serveronly, then the bytecode has to match the nodejs standalone engine version

OK, thanks.
It seems that rebuild have corrected the error for the module.
When I try to run a node-command in the shell (terminal) then I get an similar error message as above.
Is this caused by your explanation part above?
Different versions needed for either terminal or inside mirror?
Can you tell me HOW the magic mirror is started (when I have used your install script)?

Is there a way to test something which had to run in the mirror (like the module) on commandline?

To illustrate what I mean:
I have a very short test-script test-gpiod.js

// test-gpiod.js , Aug 2025, Dr. Ralf Korell
const { Chip } = require("node-libgpiod");
try {
  const chip = new Chip(0);
  console.log("Chip label:", chip.getChipLabel());
} catch (err) {
  console.error("Error loading chip:", err);
}

which I try to run with

node test-gpiod.js

But this produces error message:

/home/pi/MagicMirror/modules/MMM-PresenceScreenControl/node_modules/bindings/bindings.js:121
throw e;
^

Error: The module '/home/pi/MagicMirror/modules/MMM-PresenceScreenControl/node_modules/node-libgpiod/build/Release/node-libgpiod.node'
was compiled against a different Node.js version using
NODE_MODULE_VERSION 128. This version of Node.js requires
NODE_MODULE_VERSION 115. Please try re-compiling or re-installing
the module (for instance, using `npm rebuild` or `npm install`).
at Module._extensions..node (node:internal/modules/cjs/loader:1586:18)
at Module.load (node:internal/modules/cjs/loader:1288:32)
at Module._load (node:internal/modules/cjs/loader:1104:12)
at Module.require (node:internal/modules/cjs/loader:1311:19)
at require (node:internal/modules/helpers:179:18)
at bindings (/home/pi/MagicMirror/modules/MMM-PresenceScreenControl/node_modules/bindings/bindings.js:112:48)
at Object.<anonymous> (/home/pi/MagicMirror/modules/MMM-PresenceScreenControl/node_modules/node-libgpiod/lib/misc.js:1:37)
at Module._compile (node:internal/modules/cjs/loader:1469:14)
at Module._extensions..js (node:internal/modules/cjs/loader:1548:10)
at Module.load (node:internal/modules/cjs/loader:1288:32) {
code: 'ERR_DLOPEN_FAILED'
}

Node.js v20.18.1

Thanks for any help!
Warmest regards,
Ralf

sdetweil

@rkorell MM is started by doing node --run or npm start or npm run start

that matches a script in the scripts section of package.json

the MagicMirror installed files support 3 different runtimes

npm start - full using electron

		"start:x11": "DISPLAY=\"${DISPLAY:=:0}\" ./node_modules/.bin/electron  js/electron.js",

npm run server - server mode only , using node engine

		"server": "node ./serveronly",

npm run client - UI mode using electron

node clientonly --address 192.168.1.5 --port 8080

which does this to launch electron, not it doesn’t use the module node_helpers, as its the UI portion
only… the server side (under full, or server only) does that

const child = require("node:child_process").spawn(electron, elecParams, options);

as I said before, the electron embedded node engines CAN be different than the install standalone nodejs version

node -v
will tell you the standalone node js version.

the problem you have, I mentioned in the prior post, if the node versions don’t match, then
you MAY have to recompile when switching runtime choices…

npm rebuild

will fix the standalone node version

electron-rebuild

will fix the electron version

I believe the current electron version is 22, and the node version we require is 22

this is because the standalone node version of 24 has dropped support for 32 bit runtimes… and knocks out using the
32 bit legacy raspi OS images that some use…

we put out a message to tell the versions when you start MM

VERSIONS: electron: 36.6.0; used node: 22.15.0; installed node: 22.15.0; npm: 10.9.2; pm2: 6.0.8

SO… fun times… keeping the node versions synched will avoid the problem you are encountering

rkorell

@sdetweil
Dear Sam, OK, thanks for this.
Not fully understood…

How can I

figure out, how my mirror is started? (looooong ago I‘ve used your install script and (if I remember correctly) I‘ve answered „yes“ to „do you want automatically start your mirror at system startup“ - or something similar. - Never took care about, what is done - it worked (and still works)…)
double check the above „VERSIONS“ - message - is this message in logfile?
can I get „keeping the node versions synched“?

Thanks for further advise!
Warmest regards,
Ralf

sdetweil

@rkorell 1. my pm2 setup uses the file

~/MagicMirror/installers/mm.sh

you can see that by using the

pm2 info xxxx

command, where xxx is the name or number of the app row in

pm2 status

output, from my desktop , note you CAN setup the SAME NAMED app multiple times,
so the pm2 start app_name
might be ambiguous
so pm2 start 8 would target the app on line 8

┌────┬─────────────────────┬─────────────┬─────────┬─────────┬──────────┬────────┬──────┬───────────┬──────────┬──────────┬──────────┬──────────┐
│ id │ name                │ namespace   │ version │ mode    │ pid      │ uptime │ ↺    │ status    │ cpu      │ mem      │ user     │ watching │
├────┼─────────────────────┼─────────────┼─────────┼─────────┼──────────┼────────┼──────┼───────────┼──────────┼──────────┼──────────┼──────────┤
│ 8  │ MagicMirror         │ default     │ 2.32.0… │ fork    │ N/A      │ 0      │ 245… │ stopped   │ 0%       │ 0b       │ sam      │ disabled │
│ 7  │ MagicMirror 8       │ default     │ 2.31.0… │ fork    │ N/A      │ 0      │ 8    │ stopped   │ 0%       │ 0b       │ sam      │ disabled │
│ 6  │ MagicMirror1        │ default     │ 2.31.0… │ fork    │ N/A      │ 0      │ 13   │ stopped   │ 0%       │ 0b       │ sam      │ disabled │
│ 0  │ Smart Mirror        │ default     │ 0.0.30  │ fork    │ N/A      │ 0      │ 31   │ stopped   │ 0%       │ 0b       │ sam      │ disabled │
│ 2  │ checkarec           │ default     │ N/A     │ fork    │ 2870     │ 19D    │ 0    │ online    │ 0%       │ 3.4mb    │ sam      │ disabled │
│ 5  │ smart-mirror        │ default     │ 0.0.31  │ fork    │ N/A      │ 0      │ 8    │ stopped   │ 0%       │ 0b       │ sam      │ disabled │
│ 4  │ smart-mirror ttt    │ default     │ 0.0.30  │ fork    │ N/A      │ 0      │ 10   │ stopped   │ 0%       │ 0b       │ sam      │ disabled │
│ 3  │ start_alexa_bk      │ default     │ N/A     │ fork    │ 2871     │ 19D    │ 0    │ online    │ 0%       │ 2.4mb    │ sam      │ disabled │
│ 1  │ startspot           │ default     │ N/A     │ fork    │ 6315     │ 19D    │ 439  │ online    │ 0%       │ 2.5mb    │ sam      │ disabled │
│ 9  │ testups             │ default     │ N/A     │ fork    │ 2885     │ 19D    │ 0    │ online    │ 0%       │ 3.2mb    │ sam

using pm2, you can view the log with

pm2 logs yyy --lines=xxxx

yyy is the name or number of the app from status above), if not supplied,
output from all managed apps is displayed, 1 after the others

xxxx is the count of most recent lines to display (default 15)

you can also see the files(.out and .err, by app) in the

~/.pm2/logs

folder

MM puts out a messages at runtime (this from my desktop system)

[2025-08-09 09:47:38.743] [INFO]  System information:
### SYSTEM:   manufacturer: System manufacturer; model: System Product Name; virtual: false
### OS:       platform: linux; distro: Ubuntu; release: 22.04.5 LTS; arch: x64; kernel: 5.15.0-144-generic
### VERSIONS: electron: 36.6.0; used node: 22.15.0; installed node: 22.15.0; npm: 10.9.2; pm2: 6.0.8
### OTHER:    timeZone: America/Chicago; ELECTRON_ENABLE_GPU: undefined

notice the versions line

keep the node versions synced… yes manually (I use the nodejs version of nvm, called n )
if installed this will show the versions installed

n list

and

will show the list AND the current one, but you have to type q to exit the list
(because n updates the /usr/local/bin folder, you have to use sudo to actually install or change the active version)

or
if you use my install/upgrade script they will make sure the correct standalone version is installed

my scripts install and use n if needed to change versions

rkorell

@sdetweil Dear Sam,
thanks again for this long explanation!

My versions (if I interpret correctly) doesn’t mismatch :-(

0|MagicMir | ### SYSTEM:   manufacturer: ; model: ; virtual: false
0|MagicMir | ### OS:       platform: linux; distro: Debian GNU/Linux; release: 12; arch: arm64; kernel: 6.12.20+rpt-rpi-2712
0|MagicMir | ### VERSIONS: electron: 32.2.7; used node: 20.18.1; installed node: 20.18.1; npm: 10.8.2; pm2: 5.4.3
0|MagicMir | ### OTHER:    timeZone: Europe/Berlin; ELECTRON_ENABLE_GPU: undefined

So I’m not sure at all, what to do.

pi@MagicMirrorPi5:~ $ n list
node/20.18.1

Does show up exact this version, as well.
Where are my problems from ???
Thanks a LOT for any idea!

Ralf

sdetweil

@rkorell

so, if, in the module folder you do

npm rebuild

it will fix the version to the standalone node engine

if you do

electron-rebuild

it should fix the version to the electron embedded node engine

if the engine is the same, only one of those is required