[pve-devel] [PATCH storage 1/1] esxi: improve error handling for fuse mount tool

[Thomas Lamprecht]

On 08/05/2024 14:41, Dominik Csapak wrote:
> if the fuse tool encounters an error early, it prints it like:
>    Error: some error message
> on stderr.
> 
> We can capture that here by redirecting STDERR to $wr and die'ing with

using just a variable name like $wr without context in a commit message
is hardly telling or useful, maybe replace above and the paragraph below
with something like:

"Redirect the STDERR of the child process that mounts the ESXi instance to
the pipe of the parent (API) process, so that it can pass a hopefully more
meaningful message to the user than just an erroneous return code."


> the error message.
> 
> With this we die with the original error message instead of only
> with the return code which is telling the user nothing and does not
> help us debug.
> 
> Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
> ---
>  src/PVE/Storage/ESXiPlugin.pm | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/src/PVE/Storage/ESXiPlugin.pm b/src/PVE/Storage/ESXiPlugin.pm
> index b8bce0e..8dc33fc 100644
> --- a/src/PVE/Storage/ESXiPlugin.pm
> +++ b/src/PVE/Storage/ESXiPlugin.pm
> @@ -222,6 +222,10 @@ sub esxi_mount : prototype($$$;$) {
>  		// die "failed to get file descriptor flags: $!\n";
>  	    fcntl($wr, F_SETFD, $flags & ~FD_CLOEXEC)
>  		// die "failed to remove CLOEXEC flag from fd: $!\n";
> +
> +	    # capture errors from stderr

nit: you capture all that gets printed to stderr, not just errors, and no
hard feelings, but the comment feels a tiny bit superfluous, at least with
the error message.

> +	    open(STDERR, ">&", \*$wr) or die "unable to redirect STDERR: $!\n";

Don't the \ reference operator and the * dereference operator here cancel
each other out?

> +
>  	    # FIXME: use the user/group options!
>  	    exec {$ESXI_FUSE_TOOL}
>  		$ESXI_FUSE_TOOL,
> @@ -245,7 +249,7 @@ sub esxi_mount : prototype($$$;$) {
>      undef $wr;
>  
>      my $result = do { local $/ = undef; <$rd> };
> -    if ($result =~ /^ERROR: (.*)$/) {
> +    if ($result =~ /^ERROR: (.*)$/i) {
>  	die "$1\n";
>      }
>