Allow values to be specified as arithmetic expressions written in Lisp-like

prefix notation.  Use this to compute the cache hit ratio in the same
manner as the Nagios plugin does, and to compute cache file usage.

git-svn-id: svn+ssh://projects.linpro.no/svn/varnish/trunk@1769 d4fa192b-c00b-0410-8231-f00ffab90ce4

diff --git a/varnish-tools/munin/varnish_munin_plugin.pl b/varnish-tools/munin/varnish_munin_plugin.pl
index 84793a604bea7d8c6c65601b64bbd56caa830a4e..1598b0277ee7981d73c0c4e02a71d6e1637ba89a 100755 (executable)
--- a/varnish-tools/munin/varnish_munin_plugin.pl
+++ b/varnish-tools/munin/varnish_munin_plugin.pl
@@ -37,24 +37,63 @@ our %ASPECTS = (
     'ratio' => {
        'title' => 'Hit / miss ratio',
        'type' => 'percent',
+       'order' => [ 'hit', 'miss' ],
        'values' => {
            'hit' => {
                'label' => 'hits',
                'numerator' => 'cache_hit',
-               'denominator' => 'client_req',
+               'denominator' => [ '+', 'cache_hit', 'cache_miss' ],
            },
            'miss' => {
                'label' => 'misses',
                'numerator' => 'cache_miss',
-               'denominator' => 'client_req',
+               'denominator' => [ '+', 'cache_hit', 'cache_miss' ],
+           },
+       },
+    },
+    'usage' => {
+       'title' => 'Cache file usage',
+       'type' => 'percent',
+       'order' => [ 'used', 'free' ],
+       'values' => {
+           'used' => {
+               'label' => 'used',
+               'numerator' => 'sm_balloc',
+               'denominator' => [ '+', 'sm_balloc', 'sm_bfree' ],
+           },
+           'free' => {
+               'label' => 'free',
+               'numerator' => 'sm_bfree',
+               'denominator' => [ '+', 'sm_balloc', 'sm_bfree' ],
            },
        },
     },
 );
 
+sub varnishstat($);
 sub varnishstat($) {
     my $field = shift;
 
+    if (ref($field) eq 'ARRAY') {
+       die "Too few terms in $field"
+           if @$field < 2;
+       my $acc = varnishstat($$field[1]);
+
+       foreach (@$field[2..$#$field]) {
+           if ($$field[0] eq '+') {
+               $acc += varnishstat($_);
+           } elsif ($$field[0] eq '-') {
+               $acc -= varnishstat($_);
+           } elsif ($$field[0] eq '*') {
+               $acc *= varnishstat($_);
+           } elsif ($$field[0] eq '/') {
+               $acc /= varnishstat($_);
+           } else {
+               die "Invalid spec for $field\n";
+           }
+       }
+       return $acc;
+    }
     die "no such field: $field\n"
        unless defined($varnishstat{$field});
     return $varnishstat{$field};
@@ -80,11 +119,19 @@ sub value($$) {
     }
 }
 
+sub order($) {
+    my $aspect = shift;
+
+    return (@{$aspect->{'order'}})
+       if (defined($aspect->{'order'}));
+    return (sort(keys(%{$aspect->{'values'}})));
+}
+
 sub measure($) {
     my $aspect = shift;
 
     defined($aspect) || die "oops";
-    my @order = $aspect->{'order'} || sort(keys(%{$aspect->{'values'}}));
+    my @order = order($aspect);
     foreach (@order) {
        print "$_.value ",
            value($aspect->{'values'}->{$_}, $aspect->{'type'}),
@@ -101,7 +148,7 @@ sub config($) {
     if ($aspect->{'type'} eq 'percent') {
        print "graph_scale no\n";
     }
-    my @order = $aspect->{'order'} || sort(keys(%{$aspect->{'values'}}));
+    my @order = order($aspect);
     print "graph_order ", join(' ', @order), "\n";
     foreach (@order) {
        my $value = $aspect->{'values'}->{$_};