basic loadbalancer

lib/Plack/Middleware/Proxy/LoadBalancer.pm

@@ -0,0 +1,87 @@
+package Plack::Middleware::Proxy::LoadBalancer;
+use strict;
+use warnings;
+use parent 'Plack::Middleware';
+
+use Plack::Util::Accessor qw/backends/;
+
+our $VERSION = '0.01';
+
+sub select_backend {
+    my $self = shift;
+
+    if ( ref $self->backends eq 'ARRAY' ) {
+        return $self->backends->[ int( rand( @{ $self->backends } ) ) ];
+    }
+    elsif ( ref $self->backends eq 'HASH' ) {
+        return (
+            sort { $b->{value} <=> $a->{value} }
+                map { { value => rand() * $self->backends->{$_}, host => $_ }; }
+                keys %{ $self->backends }
+        )[0]->{host};
+    }
+    else {
+        return $self->backends;
+    }
+}
+
+sub call {
+    my ( $self, $env ) = @_;
+    my $url = $self->select_backend();
+    $env->{'plack.proxy.remote'} = $self->select_backend;
+    $self->app->($env);
+}
+
+1;
+
+__END__
+
+=head1 NAME
+
+Plack::Middleware::Proxy::LoadBalancer - Simple load balancer
+
+=head1 SYNOPSIS
+
+  use Plack::Builder;
+  use Plack::App::Proxy;
+
+  builder {
+    enable "Proxy::LoadBalancer", backends => ['10.0.0.1:8080', '10.0.0.1:8081'];
+    Plack::App::Proxy->new()->to_app;
+  };
+
+=head1 DESCRIPTION
+
+Plack::Middleware::Proxy::LoadBalancer allow you to define several backends.
+
+=head1 OPTIONS
+
+=over 4
+
+=item backends
+
+  enable "Proxy::LoadBalancer", backends => '10.0.0.1:8080';
+
+Or
+
+  enable "Proxy::LoadBalancer", backends => ['10.0.0.1:8080', '10.0.0.1:8081'];
+
+Or
+
+  enable "Proxy::LoadBalancer", backends => {'10.0.0.1:8080' => 0.4, '10.0.0.1:8081' => 0.5, '10.0.0.1:8002' => 0.3};
+
+More than one backend can be defined. Weight can be given to backends.
+
+=back
+
+=head1 AUTHOR
+
+Franck Cuny
+
+=head1 SEE ALSO
+
+L<Plack::App::Proxy>
+
+=cut
+
+

t/middleware/loadbalancer.t

@@ -0,0 +1,31 @@
+use strict;
+use warnings;
+use Plack::App::Proxy;
+use Plack::Middleware::Proxy::LoadBalancer;
+use Test::More;
+use Plack::App::Proxy::Test;
+
+test_proxy(
+    proxy => sub {
+        Plack::Middleware::Proxy::LoadBalancer->wrap(
+            Plack::App::Proxy->new(),
+            backends => ["http://$_[0]:$_[1]/"]),
+    },
+    app   => sub {
+        my $env = shift;
+	use YAML::Syck;
+	warn Dump $env;
+        [ 200, [ Via => '1.0 lucy' ], [ 'Hello' ] ];
+    },
+    client => sub {
+        my $cb = shift;
+        my $req = HTTP::Request->new( GET => "http://localhost/" );
+        my $res = $cb->($req);
+	ok $res;
+        #like $res->header( 'Via' ), qr/1\.0 lucy\s*,\s*\b1\.[01] /;
+        #like $res->header( 'Via' ), qr(${\ quotemeta $req->uri->host});
+        #like $res->header( 'Via' ), qr(${\ quotemeta $req->uri->port});
+    },
+);
+
+done_testing;