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Search-Elasticsearch-2.03
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/ Search::Elasticsearch

NAME

Search::Elasticsearch - The official client for Elasticsearch

VERSION

version 2.03

SYNOPSIS

use Search::Elasticsearch;

# Connect to localhost:9200:

my $e = Search::Elasticsearch->new();

# Round-robin between two nodes:

my $e = Search::Elasticsearch->new(
    nodes => [
        'search1:9200',
        'search2:9200'
    ]
);

# Connect to cluster at search1:9200, sniff all nodes and round-robin between them:

my $e = Search::Elasticsearch->new(
    nodes    => 'search1:9200',
    cxn_pool => 'Sniff'
);

# Index a document:

$e->index(
    index   => 'my_app',
    type    => 'blog_post',
    id      => 1,
    body    => {
        title   => 'Elasticsearch clients',
        content => 'Interesting content...',
        date    => '2013-09-24'
    }
);

# Get the document:

my $doc = $e->get(
    index   => 'my_app',
    type    => 'blog_post',
    id      => 1
);

# Search:

my $results = $e->search(
    index => 'my_app',
    body  => {
        query => {
            match => { title => 'elasticsearch' }
        }
    }
);

# Cluster requests:

$info        = $e->cluster->info;
$health      = $e->cluster->health;
$node_stats  = $e->cluster->node_stats;

# Index requests:

$e->indices->create(index=>'my_index');
$e->indices->delete(index=>'my_index');

DESCRIPTION

Search::Elasticsearch is the official Perl client for Elasticsearch, supported by elasticsearch.com. Elasticsearch itself is a flexible and powerful open source, distributed real-time search and analytics engine for the cloud. You can read more about it on elastic.co.

BACKWARDS COMPATIBILITY

This version of the client supports the Elasticsearch 2.0 branch by default, see "Client" section below for details of working with 1.0 and 0.90 branches.

Motivation

    The greatest deception men suffer is from their own opinions.

    Leonardo da Vinci

All of us have opinions, especially when it comes to designing APIs. Unfortunately, the opinions of programmers seldom coincide. The intention of this client, and of the officially supported clients available for other languages, is to provide robust support for the full native Elasticsearch API with as few opinions as possible: you should be able to read the Elasticsearch reference documentation and understand how to use this client, or any of the other official clients.

Should you decide that you want to customize the API, then this client provides the basis for your code. It does the hard stuff for you, allowing you to build on top of it.

Features

This client provides:

  • Full support for all Elasticsearch APIs

  • HTTP backend (for an async backend using Promises, see Search::Elasticsearch::Async)

  • Robust networking support which handles load balancing, failure detection and failover

  • Good defaults

  • Helper utilities for more complex operations, such as bulk indexing, scrolled searches and reindexing.

  • Logging support via Log::Any

  • Compatibility with the official clients for Python, Ruby, PHP and Javascript

  • Easy extensibility

INSTALLING ELASTICSEARCH

You can download the latest version of Elasticsearch from http://www.elastic.co/download. See the installation instructions for details. You will need to have a recent version of Java installed, preferably the Java v7 from Sun.

CREATING A NEW INSTANCE

The "new()" method returns a new client which can be used to run requests against the Elasticsearch cluster.

use Search::Elasticsearch;
my $e = Search::Elasticsearch->new( %params );

The most important arguments to "new()" are the following:

nodes

The nodes parameter tells the client which Elasticsearch nodes it should talk to. It can be a single node, multiples nodes or, if not specified, will default to localhost:9200:

# default: localhost:9200
$e = Search::Elasticsearch->new();

# single
$e = Search::Elasticsearch->new( nodes => 'search_1:9200');

# multiple
$e = Search::Elasticsearch->new(
    nodes => [
        'search_1:9200',
        'search_2:9200'
    ]
);

Each node can be a URL including a scheme, host, port, path and userinfo (for authentication). For instance, this would be a valid node:

https://username:password@search.domain.com:443/prefix/path

See "node" in Search::Elasticsearch::Role::Cxn::HTTP for more on node specification.

cxn_pool

The CxnPool modules manage connections to nodes in the Elasticsearch cluster. They handle the load balancing between nodes and failover when nodes fail. Which CxnPool you should use depends on where your cluster is. There are three choices:

  • Static

    $e = Search::Elasticsearch->new(
    cxn_pool => 'Static'     # default
    nodes    => [
        'search1.domain.com:9200',
        'search2.domain.com:9200'
    ],
);

    The Static connection pool, which is the default, should be used when you don't have direct access to the Elasticsearch cluster, eg when you are accessing the cluster through a proxy. See Search::Elasticsearch::CxnPool::Static for more.

  • Sniff

    $e = Search::Elasticsearch->new(
    cxn_pool => 'Sniff',
    nodes    => [
        'search1:9200',
        'search2:9200'
    ],
);

    The Sniff connection pool should be used when you do have direct access to the Elasticsearch cluster, eg when your web servers and Elasticsearch servers are on the same network. The nodes that you specify are used to discover the cluster, which is then sniffed to find the current list of live nodes that the cluster knows about. See Search::Elasticsearch::CxnPool::Sniff.

  • Static::NoPing

    $e = Search::Elasticsearch->new(
    cxn_pool => 'Static::NoPing'
    nodes    => [
        'proxy1.domain.com:80',
        'proxy2.domain.com:80'
    ],
);

    The Static::NoPing connection pool should be used when your access to a remote cluster is so limited that you cannot ping individual nodes with a HEAD / request.

    See Search::Elasticsearch::CxnPool::Static::NoPing for more.

trace_to

For debugging purposes, it is useful to be able to dump the actual HTTP requests which are sent to the cluster, and the response that is received. This can be enabled with the trace_to parameter, as follows:

# To STDERR
$e = Search::Elasticsearch->new(
    trace_to => 'Stderr'
);

# To a file
$e = Search::Elasticsearch->new(
    trace_to => ['File','/path/to/filename']
);

Logging is handled by Log::Any. See Search::Elasticsearch::Logger::LogAny for more information.

Other

Other arguments are explained in the respective module docs.

RUNNING REQUESTS

When you create a new instance of Search::Elasticsearch, it returns a client object, which can be used for running requests.

use Search::Elasticsearch;
my $e = Search::Elasticsearch->new( %params );

# create an index
$e->indices->create( index => 'my_index' );

# index a document
$e->index(
    index   => 'my_index',
    type    => 'blog_post',
    id      => 1,
    body    => {
        title   => 'Elasticsearch clients',
        content => 'Interesting content...',
        date    => '2013-09-24'
    }
);

See Search::Elasticsearch::Client::2_0::Direct for more details about the requests that can be run.

MODULES

Each chunk of functionality is handled by a different module, which can be specified in the call to new() as shown in cxn_pool above. For instance, the following will use the Search::Elasticsearch::CxnPool::Sniff module for the connection pool.

$e = Search::Elasticsearch->new(
    cxn_pool => 'Sniff'
);

Custom modules can be named with the appropriate prefix, eg Search::Elasticsearch::CxnPool::, or by prefixing the full class name with +:

$e = Search::Elasticsearch->new(
    cxn_pool => '+My::Custom::CxnClass'
);

The modules that you can override are specified with the following arguments to "new()":

client

The class to use for the client functionality, which provides methods that can be called to execute requests, such as search(), index() or delete(). The client parses the user's requests and passes them to the "transport" class to be executed.

The default version of the client is 2_0::Direct, which can be explicitly specified as follows:

$e = Search::Elasticsearch->new(
    client => '2_0::Direct'
);

See :

transport

The Transport class accepts a parsed request from the "client" class, fetches a "cxn" from its "cxn_pool" and tries to execute the request, retrying after failure where appropriate. See:

cxn

The class which handles raw requests to Elasticsearch nodes. See:

cxn_factory

The class which the "cxn_pool" uses to create new "cxn" objects. See:

cxn_pool (2)

The class to use for the connection pool functionality. It calls the "cxn_factory" class to create new "cxn" objects when appropriate. See:

logger

The class to use for logging events and tracing HTTP requests/responses. See:

serializer

The class to use for serializing request bodies and deserializing response bodies. See:

MIGRATING FROM ElasticSearch.pm

See Search::Elasticsearch::Compat, which allows you to run your old ElasticSearch code with the new Search::Elasticsearch module.

The Search::Elasticsearch API is pretty similar to the old ElasticSearch API, but there are a few differences. The most notable are:

hosts vs servers

When instantiating a new Search::Elasticsearch instance, use nodes instead of servers:

$e = Search::Elasticsearch->new(
    nodes => [ 'search1:9200', 'search2:9200' ]
);

no_refresh

By default, the new client does not sniff the cluster to discover nodes. To enable sniffing, use:

$e = Search::Elasticsearch->new(
    cxn_pool => 'Sniff',
    nodes    => [ 'search1:9200', 'search2:9200' ]
);

To disable sniffing (the equivalent of setting no_refresh to true), do:

$e = Search::Elasticsearch->new(
    nodes    => [ 'search1:9200', 'search2:9200' ]
);

Request parameters

In the old client, you could specify query string and body parameters at the same level, eg:

$e->search(
    search_type => 'count',
    query       => {
        match_all => {}
    }
);

In the new client, body parameters should be passed in a body element:

$e->search(
    search_type => 'count',
    body        => {
        query       => {
            match_all => {}
        }
    }
);

trace_calls

The new client uses Log::Any for event logging and request tracing. To trace requests/responses in curl format, do:

# To STDERR
$e = Search::Elasticsearch->new (trace_to => 'Stderr');

# To a file
$e = Search::Elasticsearch->new (trace_to => ['File','/path/to/file.log']);

SearchBuilder

The old API integrated ElasticSearch::SearchBuilder for an SQL::Abstract style of writing queries and filters in Elasticsearch. This integration does not exist in the new client.

Bulk methods and scrolled_search()

Bulk indexing has changed a lot in the new client. The helper methods, eg bulk_index() and reindex() have been removed from the main client, and the bulk() method itself now simply returns the response from Elasticsearch. It doesn't interfere with processing at all.

These helper methods have been replaced by the Search::Elasticsearch::Bulk class. Similarly, scrolled_search() has been replaced by the Search::Elasticsearch::Scroll. These helper classes are accessible as:

$bulk   = $e->bulk_helper( %args_to_new );
$scroll = $e->scroll_helper( %args_to_new );

BUGS

This is a stable API but this implementation is new. Watch this space for new releases.

If you have any suggestions for improvements, or find any bugs, please report them to http://github.com/elasticsearch/elasticsearch-perl/issues. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc Search::Elasticsearch

You can also look for information at:

TEST SUITE

The full test suite requires a live Elasticsearch node to run, and should be run as :

perl Makefile.PL
ES=localhost:9200 make test

TESTS RUN IN THIS WAY ARE DESTRUCTIVE! DO NOT RUN AGAINST A CLUSTER WITH DATA YOU WANT TO KEEP!

You can change the Cxn class which is used by setting the ES_CXN environment variable:

ES_CXN=Hijk ES=localhost:9200 make test

AUTHOR

Clinton Gormley <drtech@cpan.org>

COPYRIGHT AND LICENSE

This software is Copyright (c) 2016 by Elasticsearch BV.

This is free software, licensed under:

The Apache License, Version 2.0, January 2004