From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Wed, 17 Jun 2015 21:43:58 +0000 (+0200)
Subject: Fix an issue where varnishcount would undercount on low traffic.
X-Git-Url: https://git.sesse.net/?p=remoteglot;a=commitdiff_plain;h=b1f81e7a5ced71f79b3d3b2212977c3901352b21

Fix an issue where varnishcount would undercount on low traffic.

Basically AnyEvent and line buffering is tricky; we could end up
reading only the first line even though there were many more ready,
causing us to see the lines from varnishncsa lines way too late
and thus oscillating between ~30 and ~0 viewers.

It's crazy that you need to fiddle with push_read() in the read
callback instead of just being able to set line => directly in the
constructor, but this is seemingly the right idiom.
---

diff --git a/varnishcount.pl b/varnishcount.pl
index 1aa0e6f..7411b05 100755
--- a/varnishcount.pl
+++ b/varnishcount.pl
@@ -12,13 +12,17 @@ open my $fh, "-|", "varnishncsa -F '%{%s}t %U %q tffb=%{Varnish:time_firstbyte}x
 	or die "varnishncsa: $!";
 my %uniques = ();
 
-my $ev = AnyEvent->io(
+my $ev = AnyEvent::Handle->new(
 	fh => $fh,
-        poll => 'r',
-	cb => sub {
-		chomp (my $input = <$fh>);
-		handle_line($input);
-	}
+	on_read => sub {
+		my ($hdl) = @_;
+		$hdl->push_read(
+			line => sub {
+				my ($hdl, $line, $eof) = @_;
+				handle_line($line);
+			}
+		);
+	},
 );
 my $ev2 = AnyEvent->timer(
 	interval => 1.0,