Error: failed to scan

[lnk3]

2025/05/07 17:06:40 failed to scan: failed to scan hardware: failed to fetch udev data for device "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-6/1-6.3/1-6.3:1.0/0003:1532:0114.0002/input/input4" with udev data: failed to parse usb: failed to parse model id: strconv.ParseUint: parsing "": invalid syntax

The device is an old keyboard.

Please let me know what other information you need.
Thank you for your work.

[brianmcgee]

I think you're seeing the same issue as here: #184.

If I'm right, it's an old udev version. I just created https://github.com/nix-community/nixos-facter/releases/tag/v0.4.0 and bumped nixos-facter in nixpkgs https://nixpkgs-tracker.ocfox.me/?pr=406460.

It contains a minimal udev check and some better error messaging.

[lnk3]

Thank you, I'll try as soon as possible and report back. Won't close the issue for now

[lnk3]

Have I referenced it correctly? @brianmcgee

> sudo $(which nix) --extra-experimental-features "flakes nix-command" run github:nix-community/nixos-facter/v0.4.0 -- --log-level debug -o facter.json
2025/05/14 19:59:13 facter.go:67: DEBUG building report system=x86_64-linux version=1
2025/05/14 19:59:13 facter.go:74: DEBUG scanning hardware features="[memory pci net serial cpu bios monitor scsi usb prom sbus sys sysfs udev block wlan]"
2025/05/14 19:59:13 root.go:140: failed to scan: failed to scan hardware: failed to fetch udev data for device "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-6/1-6.3/1-6.3:1.0/0003:1532:0114.0002/input/input4" with udev data: failed to parse usb: failed to parse model id: strconv.ParseUint: parsing "": invalid syntax

[Padraic-O-Mhuiris]

Can confirm similar behaviour as above on determinate nix installed hetzner box ccx33 running ubuntu22.04

          curl -fsSL https://install.determinate.systems/nix | sh -s -- install --no-confirm && \
          . /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh && \
          nix run \
            --option experimental-features "nix-command flakes" \
            --option extra-substituters https://numtide.cachix.org \
            --option extra-trusted-public-keys numtide.cachix.org-1:2ps1kLBUWjxIneOy1Ik6cQjb41X0iXVXeHigGmycPPE= \
            github:numtide/nixos-facter/v0.4.0 -- -o /tmp/facter.json && \

[brianmcgee]

Have I referenced it correctly? @brianmcgee

sudo $(which nix) --extra-experimental-features "flakes nix-command" run github:nix-community/nixos-facter/v0.4.0 -- --log-level debug -o facter.json
2025/05/14 19:59:13 facter.go:67: DEBUG building report system=x86_64-linux version=1
2025/05/14 19:59:13 facter.go:74: DEBUG scanning hardware features="[memory pci net serial cpu bios monitor scsi usb prom sbus sys sysfs udev block wlan]"
2025/05/14 19:59:13 root.go:140: failed to scan: failed to scan hardware: failed to fetch udev data for device "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-6/1-6.3/1-6.3:1.0/0003:1532:0114.0002/input/input4" with udev data: failed to parse usb: failed to parse model id: strconv.ParseUint: parsing "": invalid syntax

It looks correct.

Can you share the output of udevadm --version and the contents of /run/udev/data/+input:input4?

[lnk3]

> udevadm --version
249

> cat /run/udev/data/+input:input4
I:6463198
E:ID_INPUT=1
E:ID_INPUT_MOUSE=1
E:ID_VENDOR=Razer
E:ID_VENDOR_ENC=Razer
E:ID_VENDOR_ID=1532
E:ID_MODEL=DeathStalker_Ultimate
E:ID_MODEL_ENC=DeathStalker\x20Ultimate
E:ID_MODEL_ID=0114
E:ID_REVISION=0100
E:ID_SERIAL=Razer_DeathStalker_Ultimate
E:ID_TYPE=hid
E:ID_BUS=usb
E:ID_USB_INTERFACES=:030102:000000:030001:030101:fff000:
E:ID_USB_INTERFACE_NUM=00
E:ID_USB_DRIVER=usbhid
E:ID_PATH=pci-0000:00:14.0-usb-0:6.3:1.0
E:ID_PATH_TAG=pci-0000_00_14_0-usb-0_6_3_1_0
E:ID_FOR_SEAT=input-pci-0000_00_14_0-usb-0_6_3_1_0
G:seat
Q:seat
V:1

[brianmcgee]

Ok, there's the issue. We need a udev version of at least 252:

	// check udev version
	if udevVersion, err := udev.Version(); err != nil {
		log.Fatalf("failed to get systemd version: %v", err)
	} else if udevVersion < 252 {
		log.Fatalf("udev version %d is too old, please upgrade to at least 252", udevVersion)
	}

That check is in 0.4.0, I don't know how it's not catching your udev version. The command you shared above for running 0.4.0 looks correct. 🤷

[bryandph]

I'm also seeing this inability to detect udev version on an older Ubuntu system. I was able to get through generation by filling in 0 for the missing values on udev version 249, but that doesn't address the issue in a satisfactory way.

I don't know how it's not catching your udev version. The command you shared above for running 0.4.0 looks correct. 🤷

It looks like udevadm is a modern version (from nixpkgs) when running from the cli on a system with old udev:

sudo nix run github:bryandph/nixos-facter/udev-version -- -o facter.json --log-level debug

2025/12/05 03:45:24 INFO udev version detected version=258

2025/12/05 03:45:24 INFO udevadm command path path=/nix/store/wqay8yh6wwz70423ldm0cpx8zjrxpmbq-systemd-minimal-258.2/bin/udevadm
2025/12/05 03:45:24 facter.go:71: DEBUG building report system=x86_64-linux version=1
2025/12/05 03:45:24 facter.go:78: DEBUG scanning hardware features="[memory pci net serial cpu bios monitor scsi usb prom sbus sys sysfs udev block wlan]"
2025/12/05 03:45:24 root.go:141: failed to scan: failed to scan hardware: failed to fetch udev data for device "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0/0003:04F3:228B.0003/input/input20" with udev data: failed to parse usb: failed to parse model id: strconv.ParseUint: parsing "": invalid syntax

$> udevadm --version
249
$> which udevadm
/usr/bin/udevadm

systemd-minimal is providing the modern udevadm version. Seems like udevadm still works just fine, but the data it returns is using the old format as that's what the host udev is putting in the relevant paths.

To fix version checking we need to look at the program wrapping in package.nix. I tried removing the postInstall systemdMinimal wrapper, but that resulted in udevadm not being found on PATH. I suspect something can be done around the wrapProgram to add common paths like /usr/bin before falling back to the systemdMinimal version.

It might be better to handle back to udev version 249 as a warning to the user and still support the old identifier format. eg ID_MODEL_ID -> ID_USB_MODEL_ID, ID_VENDOR_ID -> ID_USB_VENDOR_ID, ID_REVISION -> ID_USB_REVISION as those are the only ones being type cast and throwing errors, but there are others in the Usb struct that would need updating too but don't throw errors when you handle the type casting issue.

nixos-facter/pkg/udev/udev.go

Lines 141 to 172 in 55a0bd7

	result := &Usb{
	Model: env["ID_USB_MODEL"],
	Vendor: env["ID_USB_VENDOR"],
	Serial: env["ID_SERIAL"],
	Type: env["ID_USB_TYPE"],
	Interfaces: env["ID_USB_INTERFACES"],
	InterfaceNum: env["ID_USB_INTERFACE_NUM"],
	Driver: env["ID_USB_DRIVER"],
	}
	modelID, err := strconv.ParseUint(env["ID_USB_MODEL_ID"], 16, 16)
	if err != nil {
	return nil, fmt.Errorf("failed to parse model id: %w", err)
	}
	result.ModelID = uint16(modelID)
	vendorID, err := strconv.ParseUint(env["ID_USB_VENDOR_ID"], 16, 16)
	if err != nil {
	return nil, fmt.Errorf("failed to parse vendor id: %w", err)
	}
	result.VendorID = uint16(vendorID)
	revision, err := strconv.ParseUint(env["ID_USB_REVISION"], 16, 16)
	if err != nil {
	return nil, fmt.Errorf("failed to parse revision: %w", err)
	}
	result.Revision = uint16(revision)
	return result, nil