/ 
ElasticSearch-0.22
/ ElasticSearch::Transport

NAME

ElasticSearch::Transport - Base class for communicating with ElasticSearch

DESCRIPTION

ElasticSearch::Transport is a base class for the modules which communicate with the ElasticSearch server.

It handles failover to the next node in case the current node closes the connection. All requests are round-robin'ed to all live servers.

Currently, the available backends are:

You shouldn't need to talk to the transport modules directly - everything happens via the main ElasticSearch class.

SYNOPSIS

use ElasticSearch;
my $e = ElasticSearch->new(
    servers     => 'search.foo.com:9200',
    transport   => 'httplite',
    timeout     => '10',
);

my $t = $e->transport;

$t->protocol                    # eg 'http'
$t->next_server                 # next node to use
$t->current_server              # eg '127.0.0.1:9200' ie last used node
$t->default_servers             # seed servers passed in to new()

$t->servers                     # eg ['192.168.1.1:9200','192.168.1.2:9200']
$t->servers(@servers);          # set new 'live' list

$t->refresh_servers             # refresh list of live nodes

$t->clear_clients               # clear all open clients

$t->register('foo',$class)      # register new Transport backend

WHICH TRANSPORT SHOULD YOU USE

Although the thrift interface has the right buzzwords (binary, compact, sockets), the Perl backend is very slow. Until that is improved, I recommend one of the http backends instead.

The httplite backend is about 30% faster than the default http backend, and will probably become the default after more testing in production.

Note: my experience with HTTP::Lite so far has been flawless - I'm just being cautious.

SUBCLASSING TRANSPORT

If you want to add a new transport backend, then these are the methods that you should subclass:

init()

$t->init($params)

Currently a no-op. Receives a HASH ref with the parameters passed in to new(), less servers, transport and timeout.

Any parameters specific to your module should be deleted from $params

send_request()

$json = $t->send_request($server,$params)

where $params = {
    method  => 'GET',
    cmd     => '/_cluster',
    qs      => { pretty => 1 },
    data    => '{ "foo": "bar"}',
}

This must be overridden in the subclass - it is the method called to actually talk to the server.

See ElasticSearch::Transport::HTTP for an example implementation.

protocol()

$t->protocol

This must return the protocol in use, eg "http" or "thrift". It is used to extract the list of bound addresses from ElasticSearch, eg http_address or thrift_address.

client()

$client = $t->client($server)

Returns the client object used in "send_request()". The server param will look like "192.168.5.1:9200". It should store its clients in a PID specific slot in $t->{_client} as clear_clients() deletes this key.

See "client()" in ElasticSearch::Transport::HTTP and "client()" in ElasticSearch::Transport::Thrift for an example implementation.

Registering your Transport backend

You can register your Transport backend as follows:

BEGIN {
    ElasticSearch::Transport->register('mytransport',__PACKAGE__);
}

SEE ALSO

LICENSE AND COPYRIGHT

Copyright 2010 Clinton Gormley.

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.