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@mala
Created May 13, 2009 11:44
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package Cache::Migrate;
use strict;
use warnings;
use Carp;
use base qw(Class::Accessor::Fast);
__PACKAGE__->mk_accessors(qw(debug));
our $VERSION = "0.01";
sub new {
my $class = shift;
my @opt = @_;
my $self;
if (exists $opt[0]->{caches}) {
$self = {
debug => $opt[0]->{debug} || 0,
_cache => $opt[0]->{caches}
};
} else {
$self = {
_cache => \@opt
};
}
bless $self, $class;
}
# delegate setting
# read request: get,gets
# write request: set,add,replace,cas,incr,decr,append,prepend,delete
BEGIN {
my @read = qw(get gets);
my @read_multi = map { $_ ."_multi" } @read;
my @write = qw(set add replace cas incr decr append prepend delete);
my @write_multi = map { $_ ."_multi" } @write;
for my $method_name (@read, @read_multi) {
eval sprintf(<<'__SUB__', $method_name, $method_name);
sub %s {
my $self = shift;
$self->_delegate_read("%s", @_);
}
__SUB__
warn $@ if $@;
}
for my $method_name (@write, @write_multi) {
eval sprintf(<<'__SUB__', $method_name, $method_name);
sub %s {
my $self = shift;
$self->_delegate_write("%s", @_);
}
__SUB__
warn $@ if $@;
}
}
# select usable cache engine
sub _select_usable_cache {
my $self = shift;
return map { $_->{cache} } grep {
!exists $_->{expires_on} || time < $_->{expires_on}
} @{$self->{_cache}};
}
# read from first usable cache object
sub _delegate_read {
my $self = shift;
my ($method, @args) = @_;
my ($cache) = $self->_select_usable_cache;
if (!$cache) {
carp "can't find usable cache!" if $self->debug;
return;
}
$cache->$method(@args);
}
# write for all usable cache object
sub _delegate_write {
my $self = shift;
my ($method, @args) = @_;
my @all = $self->_select_usable_cache;
my @result;
my $result;
if (!@all) {
carp "can't find usable cache!" if $self->debug;
return;
}
warn sprintf("%d usable cache object(s)", scalar @all) if $self->debug;
for my $cache (@all) {
if (wantarray) {
@result = $cache->$method(@args);
} else {
$result = $cache->$method(@args);
}
}
return wantarray ? @result : $result;
}
1;
__END__
=pod
=head1 NAME
Cache::Migrate
=head1 SYNOPSIS
use Cache::Migrate;
use Date::Parse;
use Cache::Memcached::Fast;
$old_cache = Cache::Memcached::Fast->new({servers => ["127.0.0.1:11211"] });
$new_cache = Cache::Memcached::Fast->new({servers => ["127.0.0.1:11212"] });
$cache = Cache::Migrate->new(
{ cache => $old_cache, expires_on => str2time("2009/05/15 00:00:00") },
{ cache => $new_cache },
);
or
$cache = Cache::Migrate->new({
debug => 1,
caches => [
{ cache => $old_cache, expires_on => str2time("2009/05/15 00:00:00") },
{ cache => $new_cache },
],
});
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