fix(nixos-generate-config): dont output carriage returns in output files

[sedlund]

ssh -t is being used by runSsh which causes new lines in output designed for a terminal. It could also output escape sequences.

https://unix.stackexchange.com/a/420438

this change fixes this problem (#438) by only outputting new lines. but it might be worth removing ssh password entry as an option and the tty allocation, and force the use of sshpass for passwords.

There is a FIXME note regarding the output of the nixos-facter with strange characters. This may resolve that as well.

Also updated the message about nixos-facter not being found to hopefully clarify and resolve #423 around the --generate-hardware-config option.

[Mic92]

What version did you use for nixos-facter? We switched logging libraries at some point, which resolved an issue with ANSI escapes.

[sedlund]

should have quoted:

nixos-anywhere/src/nixos-anywhere.sh

Lines 457 to 459 in bf4c0c5

	step "Generating hardware-configuration.nix using nixos-facter"
	# FIXME: if we take the output directly it adds some weird characters at the beginning
	runSsh -o ConnectTimeout=10 ${maybeSudo} "nixos-facter" >"$hardwareConfigPath"

I was unsure what 'weird characters' referred to.

So maybe what you refer to fixed that, but CRLF in output persists with tty allocation with ssh.

I tested with:

ssh -t localhost nixos-generate-config --show-hardware-config --no-filesystems > ngc-old.out
ssh -t localhost "stty nl; nixos-generate-config --show-hardware-config --no-filesystems" > ngc-new.out
ssh -t localhost sudo nixos-facter > facter-old.out
ssh -t localhost "stty nl; sudo nixos-facter" > facter-new.out

fd -e out -x nix shell nixpkgs#tinyxxd -c xxd {} {.}.xxd

file *.out
facter-new.out: JSON text data
facter-old.out: JSON text data
ngc-new.out:    Unicode text, UTF-8 text
ngc-old.out:    Unicode text, UTF-8 text, with CRLF line terminators

delta --side-by-side ngc-old.xxd ngc-new.xxd
delta --side-by-side facter-old.xxd facter-new.xxd

this is qpqn0b91qbh879snbqpr04z8rdi7zkq8-nixos-facter-0.3.0.

diffs show CRLF in the old output

[Mic92]

We can remove the comment. It was caused by charm bracelet's logging library: numtide/nixos-facter#119
It wrote some ansi escape at the very beginning, which broke the json output. However this was removed.

[Mic92]

Are you running on macOS on the host by chance?

[Mic92]

But I think you are write, we shouldn't use -t for these commands. It's only needed for the installation because we need support for sudo and other password prompts.

[Mic92]

Could you try to remove it and see if this is fixing the issue?

[sedlund]

Are you running on macOS on the host by chance?

my client is NixOS-wsl. dont know what reporter in #438 is running.

created a new runSshNoTty function that omits the tty request.

tested outputs of both nixos-facter and nixos-generate-config on a hetzner vm - no CRLF in this patched version.

[Mic92]

@Enzime this is also what we saw the other day. But with macOS line endings.

[Mic92]

@mergify queue

[mergify]

queue

✅ The pull request has been merged automatically

The pull request has been merged automatically at 24f2d37