Attachment 32872 Details for Bug 11998 – Bug 11998 - sysprefs in memcached

[patch] Bug 11998 - sysprefs in memcached

Bug-11998---sysprefs-in-memcached.patch (text/plain), 4.75 KB, created by Brendan Gallagher on 2014-10-28 21:45:36 UTC

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Creator: Brendan Gallagher

Created: 2014-10-28 21:45:36 UTC

Size: 4.75 KB

patch

obsolete

>From 559ee2105ed3490b7fd0af59c974f8fff6c5d3db Mon Sep 17 00:00:00 2001
>From: Robin Sheat <robin@catalyst.net.nz>
>Date: Tue, 1 Apr 2014 16:16:29 +1300
>Subject: [PATCH] Bug 11998 - sysprefs in memcached
>
>The caching mechanism has been abstracted a little bit, and now supports
>memcached for storing sysprefs. These should be correctly stored and
>cleared so caching will work between processes.
>
>Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>
>---
> C4/Context.pm |   82 ++++++++++++++++++++++++++++++++++++++++++++++-----------
> 1 file changed, 66 insertions(+), 16 deletions(-)
>
>diff --git a/C4/Context.pm b/C4/Context.pm
>index c5e61d6..301e22a 100644
>--- a/C4/Context.pm
>+++ b/C4/Context.pm
>@@ -518,6 +518,63 @@ sub ModZebrations {
> 	return _common_config($_[1],'serverinfo');
> }
> 
>+=head2 _cache_preference($variable, [$value])
>+
>+  _cache_preferences('opacusercss', $css);
>+  my $val = _cach_preferences('opacusercss');
>+
>+An interface into the syspref caching. One argument to get a value, two to set
>+it. The single argument version will return C<undef> if the cache doesn't
>+contain the value. If the second argument is C<undef>, then the cache will be
>+cleared of that value.
>+
>+The cache timeout length is 30 seconds when memcache is not in use. When
>+memcache is in use, it uses the default cache time for that.
>+
>+=cut
>+
>+my %syspref_cache;
>+my $use_syspref_cache = 1;
>+
>+sub _cache_preference {
>+    return undef unless $use_syspref_cache;
>+    my $memcached        = memcached();
>+    my $memcached_prefix = "_syspref_";
>+    if ( scalar(@_) == 1 ) {
>+        my ($var) = @_;
>+        if ($memcached) {
>+            my $val = $memcached->get( $memcached_prefix . lc($var) );
>+            return $val;
>+        }
>+        else {
>+            my $now          = time;
>+            my $cache_oldest = $now - 30;
>+            return undef unless exists $syspref_cache{ lc $var };
>+            my $val = $syspref_cache{ lc $var };
>+            return undef unless $val->[0] > $cache_oldest;
>+            return $val->[1];
>+        }
>+    }
>+    elsif ( scalar(@_) == 2 ) {
>+        my ( $var, $val ) = @_;
>+        if ($memcached) {
>+            if ( !defined($val) ) {
>+                $memcached->delete( $memcached_prefix . lc($var) );
>+            }
>+            else {
>+                $memcached->set( $memcached_prefix . lc($var), $val );
>+            }
>+        }
>+        else {
>+            if ( !defined($val) ) {
>+                delete $syspref_cache{ lc $var };
>+                return;
>+            }
>+            $syspref_cache{ lc $var } = [ time, $val ];
>+        }
>+    }
>+}
>+
> =head2 preference
> 
>   $sys_preference = C4::Context->preference('some_variable');
>@@ -534,23 +591,12 @@ with this method.
> 
> =cut
> 
>-my %syspref_cache;
>-my $use_syspref_cache = 1;
>-
> sub preference {
>     my $self = shift;
>     my $var  = shift;    # The system preference to return
> 
>-    # We cache for 30 seconds, after that sysprefs are expired from the cache.
>-    # This is for persistent environments like Plack.
>-    my $now = time;
>-    my $cache_oldest = $now - 30;
>-    if ($use_syspref_cache && exists $syspref_cache{lc $var}) {
>-        # The cache contains an arrayref, first entry is the time it was
>-        # stored, the second is the value.
>-        my $cached_value = $syspref_cache{lc $var};
>-        return $cached_value->[1] if ($cached_value->[0] > $cache_oldest);
>-    }
>+    my $cached_var = _cache_preference($var);
>+    return $cached_var if defined $cached_var;
> 
>     my $dbh  = C4::Context->dbh or return 0;
> 
>@@ -568,7 +614,7 @@ sub preference {
>         $value = $dbh->selectrow_array( $sql, {}, lc $var );
>     }
> 
>-    $syspref_cache{lc $var} = [$now, $value];
>+    _cache_preference($var, $value);
>     return $value;
> }
> 
>@@ -620,6 +666,10 @@ will not be seen by this process.
> 
> sub clear_syspref_cache {
>     %syspref_cache= ();
>+    # It doesn't seem to be possible to list all the keys via Cache::Memcached
>+    # so we'll clear the whole cache.
>+    my $memcached = memcached();
>+    $memcached->flush_all if $memcached;
> }
> 
> =head2 set_preference
>@@ -665,7 +715,7 @@ ON DUPLICATE KEY UPDATE value = VALUES(value)';
>     }
>     my $sth = $dbh->prepare($query);
>     if ( $sth->execute(@params) ) {
>-        $syspref_cache{$var} = [ time, $value ];
>+        _cache_preference($var, $value);
>         logaction( 'SYSTEMPREFERENCE', $logtype, undef, $var . " | " . $value );
>     }
>     $sth->finish;
>@@ -690,7 +740,7 @@ sub delete_preference {
>     my $sth = $dbh->prepare("DELETE FROM systempreferences WHERE variable=?");
>     my $res = $sth->execute($var);
>     if ($res) {
>-        delete $syspref_cache{$var};
>+        C4::Context->set_preference($var, undef);
>         logaction( 'SYSTEMPREFERENCE', 'DELETE', undef,
>             $var . " | " . ( $var // 'undefined' ) );
>         return 1;
>-- 
>1.7.10.4

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