Extension:CirrusSearch/cs

The CirrusSearch extension implements searching for MediaWiki using Elasticsearch.

Elasticsearch is a standalone third-party software you must install as a requirement for this extension. It is a database system that provides search and indexing functionality, where the current text of your wiki pages gets indexed for faster and improved search results. The communication between MediaWiki and ElasticSearch is done through web services.

See also the help page on using this extension.

Goals

 * No native dependencies that would make this difficult to install
 * The only dependencies are pure-PHP MediaWiki extensions and Elasticsearch itself
 * Provide a near-real-time search index for wiki pages that's extendable by other MediaWiki extensions
 * Provide all of the query options has given users, and more

Dependencies

 * PHP and cURL
 * In addition to the standard MediaWiki requirements for PHP, CirrusSearch requires PHP to be compiled with cURL support.
 * Note that Elasticsearch versions prior to 6.8 are not compatible with PHP 8.
 * Elasticsearch
 * You will need to install Elasticsearch.

Every version of ElasticSearch change how web services work, and cause compatibility problems. You must install the version of Elastic Search compatible with the version of MediaWiki you are currently using:

Take note that a Java installation like OpenJDK is needed in addition. It's best to use the official Elasticsearch Docker image or a self-hosted version. A managed product like Amazon OpenSearch (formerly Amazon Elasticsearch) can work but may require additional configuration depending on its specifics. For example, Amazon OpenSearch only listens for Elasticsearch API requests over HTTPS on port 443 (i.e. it does not expose the default Elasticsearch port 9200), so a TLS-enabled proxy (e.g. Nginx) can enable CirrusSearch to communicate with an Amazon OpenSearch cluster.


 * Elastica is a PHP library to talk to Elasticsearch. Install Elastica per the instructions below.

See.
 * Other :
 * Due to the actual handling of jobs by the CirrusSearch extension, it is advisable to set up jobs in Redis to prevent messages like Notice: unserialize: Error at offset 64870 of 65535 bytes in JobQueueDB.php and subsequent errors like Unsupported operand types.

Even though the instructions below tell you to only run Composer when installing from git, it may be necessary to issue it anyway in order to install all PHP dependencies.

Upgrading
Please follow the upgrade instructions in the CirrusSearch file.

Configuration
The configuration parameters of CirrusSearch are documented at the file. See also documentation on CirrusSearch configuration profiles.

Hooks
CirrusSearch extension defines a number of hooks that other extensions can make use of to extend the core schema and modify documents. The following hooks are available:


 * - allows to hook into the configuration for analysis
 * - allows configuration of the mapping of fields
 * - allows extensions to modify ElasticSearch document produced from a page
 * - allows extensions to process incoming and outgoing links for the document
 * - called when a batch of pages has been indexed
 * - allows extensions to add query parser features
 * - allows extensions to define rescore builder functions
 * - allows extension to declare various search components and configuration

API
CirrusSearch features can be used in API queries. Searching happens via the normal search API, ; you can use CirrusSearch-specific features, such as the   special prefix to find pages related to Marie Curie and radium: api.php?action=query&list=search&srsearch=morelike:Marie_Curie%7Cradium&srlimit=10&srprop=size&formatversion=2

Custom APIs and parameters are provided for querying CirrusSearch configuration and debug information:


 * module: 2014?action=cirrusdump
 * parameter to Special:Search or search API queries: https://en.wikipedia.org/wiki/Special:Search/cat%20dog%20chicken?cirrusDumpQuery
 * parameter to Special:Search or search API queries: https://en.wikipedia.org/wiki/Special:Search/cat%20dog%20chicken?cirrusDumpResult
 * An additional parameter,, can be passed with   to have the Lucene explanation of the score included with the result dump: https://en.wikipedia.org/wiki/Special:Search/cat%20dog%20chicken?cirrusDumpResult&cirrusExplain It can also be used to get the explanation in a human-readable format, by giving it one of the values  ,   or  , such as: https://en.wikipedia.org/wiki/Special:Search/cat%20dog%20chicken?cirrusDumpResult&cirrusExplain=pretty
 * ,,  ,   modules to obtain dump from the CirrusSearch setup: api.php?action=cirrus-config-dump&formatversion=2

Local development
Elastic Search service can be run with the Vagrant role and MediaWiki Vagrant.

For Docker, you can use a command like. Then follow the installation and configuration directions. If your web host is in a container you'll want to make sure the above container is on the same network, and in LocalSettings.php you will want to reference  as the host name. This will not have the WMF plugins but can be sufficient for basic testing.