Subject: Re: [PATCH net-next 01/12] selftests/vsock: improve logging in vmtest.sh

From: Simon Horman <[email-masked]>
Date: Mon, 27 Oct 2025 16:45:27 +0000

On Wed, Oct 22, 2025 at 06:00:05PM -0700, Bobby Eshleman wrote:
> From: Bobby Eshleman <[email-masked]>
> 
> Improve usability of logging functions. Remove the test name prefix from
> logging functions so that logging calls can be made deeper into the call
> stack without passing down the test name or setting some global. Teach
> log function to accept a LOG_PREFIX variable to avoid unnecessary
> argument shifting.
> 
> Remove log_setup() and instead use log_host(). The host/guest prefixes
> are useful to show whether a failure happened on the guest or host side,
> but "setup" doesn't really give additional useful information. Since all
> log_setup() calls happen on the host, lets just use log_host() instead.
> 
> Signed-off-by: Bobby Eshleman <[email-masked]>

...

>  log() {
> -	local prefix="$1"
> +	local redirect
> +	local prefix
>  
> -	shift
> -	local redirect=
>  	if [[ ${VERBOSE} -eq 0 ]]; then
>  		redirect=/dev/null
>  	else
>  		redirect=/dev/stdout
>  	fi
>  
> +	prefix="${LOG_PREFIX:-}"
> +
>  	if [[ "$#" -eq 0 ]]; then
> -		__log_stdin | tee -a "${LOG}" > ${redirect}
> +		if [[ -n "${prefix}" ]]; then
> +			cat | awk -v prefix="${prefix}" '{printf "%s: %s\n", prefix, $0}'

FIWIIW, I would drop cat from this line.

> +		else
> +			cat
> +		fi
>  	else
> -		__log_args "$@" | tee -a "${LOG}" > ${redirect}
> -	fi
> -}
> -
> -log_setup() {
> -	log "setup" "$@"
> +		if [[ -n "${prefix}" ]]; then
> +			echo "${prefix}: " "$@"
> +		else
> +			echo "$@"
> +		fi
> +	fi | tee -a "${LOG}" > ${redirect}
>  }
>  
>  log_host() {
> -	local testname=$1
> -
> -	shift
> -	log "test:${testname}:host" "$@"
> +	LOG_PREFIX=host log $@

shellcheck suggests keeping the quoting of $@.
This seems reasonable to me. Although in practice I don't think
it will change the behaviour of this script.

>  }
>  log_host
>  log_guest() {
> -	local testname=$1
> -
> -	shift
> -	log "test:${testname}:guest" "$@"
> +	LOG_PREFIX=guest log $@

shellcheck also points out that log_guest is never passed
arguments, so $@ can be dropped. If you prefer to keep
it then, as per log_host, it seems reasonable for it to be quoted.

>  }

...