On Wed, Apr 14, 2021 at 05:10:41PM -0400, Andrew Dunstan wrote:
> That seems rather heavy-handed. The buildfarm's approach is a bit
> different. Essentially it seeks to the previous position of the log file
> before reading contents. Here is its equivalent of slurp_file:
>
> use Fcntl qw(:seek);
> sub file_lines
> {
> my $filename = shift;
> my $filepos = shift;
> my $handle;
> open($handle, '<', $filename) || croak "opening $filename: $!";
> seek($handle, $filepos, SEEK_SET) if $filepos;
> my @lines = <$handle>;
> close $handle;
> return @lines;
> }That's a bit surprising to see that you can safely open a file handle with perl like that without using Win32API::File, and I would have assumed that this would have conflicted with the backend redirecting its output to stderr the same way as a truncation on Windows. > A client wanting what's done in PostgresNode would do something like: > > my $logpos = -s $logfile; > do_some_stuff(); > my @lines = file_lines($logfile, $logpos); > > This has the benefit of working the same on all platforms, and no > truncation, rotation, or restart is required. Jacob has suggested something like that a couple of days ago, but all this code was not centralized yet in a single place. For this code, the cleanest approach would be to extend slurp_file() with an extra argument to seek the file before fetching its contents based on a location given by the caller? Looking at the docs of Win32API::File, we'd need to use SetFilePointer() instead of seek(). -- Michael
signature.asc
Description: PGP signature
