spencer portee > Voldemort > Voldemort

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Module Version: 0.11   Source  

NAME ^

Voldemort - A voldemort client and infrastructure

SYNOPSIS ^

Voldemort::Store is a basic client to get, delete and put data. The goal is not to be a complete POE enabled, client-side load-balancing client but a simpler sync/async client that communicates with a server. The desire is this client can be embeded in larger structures, or not.

An admin client should be coming soon.

DESCRIPTION ^

This distribution includes a few classes, the primary are:

Voldemort::Store

A top level API for communicating with a Voldemort::Connection

Voldemort::Connection

An interface for the store to communicate to a server using sync/async methods.

Voldemort::Message

An interface for message marshalling/unmarshalling messages. When a store sends a message, in asyncronous mode it will store a reference to the implemented message to unmarshall the next message.

Voldemort::Protobuff::Connection

An implementation of Voldemort::Connection using Protocol Buffers.

Voldemort::ProtoBuff::GetMessage

Voldemort::ProtoBuff::DeleteMessage

Voldemort::ProtoBuff::PutMessage

Voldemort::ProtoBuff::Spec2

Implementations of the various marshalling/unmarshalling from Protocol Buffer byte data to real data. Spec2 is a generated module for protocol buffers that is used by Get/Delete/PutMessage. They are automatically created and set when Voldemort::Connection::Protobuff is instanciated, by default.

Voldemort::ProtoBuff::Resolver

Voldemort::ProtoBuff::DefaultResolver

An interface for dealing with multiple vectors (versions) in voldemort for a given key. If vector clocks are not used, it is entirely possible to ignore this class. The implementation, DefaultResolver is defaulted when Voldemort::ProtoBuff::GetMessage is instanciated. If two vectors exist for a given piece of data, the resolver will carp. If vector clocks are not used, where all node ids are defaulting to 0, the default implementation will be fine, otherwise implement your own strategy.

Implementing your own resolver entails handling an array of Voldemort::ProtoBuff::Spec2::Versioned objects. Each element in the array represents a vector owned by an entity (or group of entites, which is a composite entity) and a value. In the USAGE section is an example that takes multiple vectors and merges the result.

USAGE ^

Quick start, no vector clocks

    use strict;
    use Moose;

    use Voldemort::Store;
    use Voldemort::ProtoBuff::Connection;

    my $connection = Voldemort::ProtoBuff::Connection->new(
        'to' => 'localhost:6666'
    );

    my $store = new Voldemort::Store( connection => $connection  );
    $store->default_store('test');
    $x->put( key=>1, value=>'5' );
    print $x->get( key=>1 );

Quick start, vector clocks

     use strict;
     use warnings;
     use Voldemort::Store;
     use Voldemort::ProtoBuff::Connection;

     my $connection = Voldemort::ProtoBuff::Connection->new(
     'to' => 'localhost:6666',
     'get_handler' =>
       Voldemort::ProtoBuff::GetMessage->new(  
        'resolver' => Foo->new() )
     );

    my $store = Voldemort::Store->new( connection => $connection );

    $store->default_store('test');

    ####
    package Foo;

    use Moose;
    use Voldemort::ProtoBuff::Resolver;

    with 'Voldemort::Protobuff::Resolver';

    sub resolve
    {
        shift;
        my $versions = shift;
        my $size = (defined $versions) ? scalar @{$versions} : 0;
        if( $size == 0 )
        {
            return (undef, []);
        }
        elsif( $size == 1 )
        {
            return $$versions[0]->value, [];
        }

        # pool everyone's likes
        my %result = ();
        my %nodes  = ();
        my @nodeRecords = ();
        foreach my $record (@{$versions})
        {
            map { $result{$_} = $_ } 
                split(/,/, $record->value);
            map { $nodes{ $_->node_id } = 1 } 
                @{$record->version->entries};
            push @nodeRecords, 
                [map {$_->node_id} @{$record->version->entries}];
        }
        return (join ",", keys %result), \@nodeRecords;
    }

BUGS ^

Zer are no more bugs! (for the moment)

SUPPORT ^

exussum@gmail.com

AUTHOR ^

Spencer Portee CPAN ID: EXUSSUM exussum@gmail.com

SOURCE ^

http://bitbucket.org/exussum/pockito/

COPYRIGHT ^

This program is free software licensed under the...

    The BSD License

The full text of the license can be found in the LICENSE file included with this module.

SEE ALSO ^

perl(1).

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