:plugin: elasticsearch
:type: filter

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:version: %VERSION%
:release_date: %RELEASE_DATE%
:changelog_url: %CHANGELOG_URL%
:include_path: ../../../../logstash/docs/include
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[id="plugins-{type}s-{plugin}"]

=== Elasticsearch filter plugin

include::{include_path}/plugin_header.asciidoc[]

==== Description

.Compatibility Note
[NOTE]
================================================================================
Starting with Elasticsearch 5.3, there's an {ref}/modules-http.html[HTTP setting]
called `http.content_type.required`. If this option is set to `true`, and you
are using Logstash 2.4 through 5.2, you need to update the Elasticsearch filter
plugin to version 3.1.1 or higher.

================================================================================

Search Elasticsearch for a previous log event and copy some fields from it
into the current event.  Below are two complete examples of how this filter might
be used.

The first example uses the legacy 'query' parameter where the user is limited to an Elasticsearch query_string.
Whenever logstash receives an "end" event, it uses this elasticsearch
filter to find the matching "start" event based on some operation identifier.
Then it copies the `@timestamp` field from the "start" event into a new field on
the "end" event.  Finally, using a combination of the "date" filter and the
"ruby" filter, we calculate the time duration in hours between the two events.

[source,ruby]
--------------------------------------------------
if [type] == "end" {
   elasticsearch {
      hosts => ["es-server"]
      query => "type:start AND operation:%{[opid]}"
      fields => { "@timestamp" => "started" }
   }

   date {
      match => ["[started]", "ISO8601"]
      target => "[started]"
   }

   ruby {
      code => "event.set('duration_hrs', (event.get('@timestamp') - event.get('started')) / 3600)"
   }
}
--------------------------------------------------

The example below reproduces the above example but utilises the query_template.
This query_template represents a full Elasticsearch query DSL and supports the
standard Logstash field substitution syntax.  The example below issues
the same query as the first example but uses the template shown.

[source,ruby]
--------------------------------------------------
if [type] == "end" {
      elasticsearch {
         hosts => ["es-server"]
         query_template => "template.json"
         fields => { "@timestamp" => "started" }
      }

      date {
         match => ["[started]", "ISO8601"]
         target => "[started]"
      }

      ruby {
         code => "event.set('duration_hrs', (event.get('@timestamp') - event.get('started')) / 3600)"
      }
}
--------------------------------------------------

template.json:

[source,json]
[source,json]
--------------------------------------------------
{
  "size": 1,
  "sort" : [ { "@timestamp" : "desc" } ],
  "query": {
    "query_string": {
      "query": "type:start AND operation:%{[opid]}"
    }
  },
  "_source": ["@timestamp"]
}
--------------------------------------------------

As illustrated above, through the use of 'opid', fields from the Logstash
events can be referenced within the template.
The template will be populated per event prior to being used to query Elasticsearch.

Notice also that when you use `query_template`, the Logstash attributes `result_size`
and `sort` will be ignored. They should be specified directly in the JSON
template, as shown in the example above.


[id="plugins-{type}s-{plugin}-options"]
==== Elasticsearch Filter Configuration Options

This plugin supports the following configuration options plus the <<plugins-{type}s-{plugin}-common-options>> described later.

[cols="<,<,<",options="header",]
|=======================================================================
|Setting |Input type|Required
| <<plugins-{type}s-{plugin}-aggregation_fields>> |<<hash,hash>>|No
| <<plugins-{type}s-{plugin}-ca_file>> |a valid filesystem path|No
| <<plugins-{type}s-{plugin}-docinfo_fields>> |<<hash,hash>>|No
| <<plugins-{type}s-{plugin}-enable_sort>> |<<boolean,boolean>>|No
| <<plugins-{type}s-{plugin}-fields>> |<<array,array>>|No
| <<plugins-{type}s-{plugin}-hosts>> |<<array,array>>|No
| <<plugins-{type}s-{plugin}-index>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-password>> |<<password,password>>|No
| <<plugins-{type}s-{plugin}-query>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-query_template>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-result_size>> |<<number,number>>|No
| <<plugins-{type}s-{plugin}-sort>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-ssl>> |<<boolean,boolean>>|No
| <<plugins-{type}s-{plugin}-tag_on_failure>> |<<array,array>>|No
| <<plugins-{type}s-{plugin}-user>> |<<string,string>>|No
|=======================================================================

Also see <<plugins-{type}s-{plugin}-common-options>> for a list of options supported by all
filter plugins.

&nbsp;

[id="plugins-{type}s-{plugin}-aggregation_fields"]
===== `aggregation_fields` 

  * Value type is <<hash,hash>>
  * Default value is `{}`

Hash of aggregation names to copy from elasticsearch response into Logstash event fields

Example:
[source,ruby]
    filter {
      elasticsearch {
        aggregation_fields => {
          "my_agg_name" => "my_ls_field"
        }
      }
    }

[id="plugins-{type}s-{plugin}-ca_file"]
===== `ca_file` 

  * Value type is <<path,path>>
  * There is no default value for this setting.

SSL Certificate Authority file

[id="plugins-{type}s-{plugin}-docinfo_fields"]
===== `docinfo_fields` 

  * Value type is <<hash,hash>>
  * Default value is `{}`

Hash of docinfo fields to copy from old event (found via elasticsearch) into new event

Example:
[source,ruby]
    filter {
      elasticsearch {
        docinfo_fields => {
          "_id" => "document_id"
          "_index" => "document_index"
        }
      }
    }

[id="plugins-{type}s-{plugin}-enable_sort"]
===== `enable_sort` 

  * Value type is <<boolean,boolean>>
  * Default value is `true`

Whether results should be sorted or not

[id="plugins-{type}s-{plugin}-fields"]
===== `fields` 

  * Value type is <<array,array>>
  * Default value is `{}`

An array of fields to copy from the old event (found via elasticsearch) into the
new event, currently being processed.

In the following example, the values of `@timestamp` and `event_id` on the event
found via elasticsearch are copied to the current event's
`started` and `start_id` fields, respectively:

[source,ruby]
--------------------------------------------------
fields => {
  "@timestamp" => "started"
  "event_id" => "start_id"
}
--------------------------------------------------

[id="plugins-{type}s-{plugin}-hosts"]
===== `hosts` 

  * Value type is <<array,array>>
  * Default value is `["localhost:9200"]`

List of elasticsearch hosts to use for querying.

[id="plugins-{type}s-{plugin}-index"]
===== `index` 

  * Value type is <<string,string>>
  * Default value is `""`

Comma-delimited list of index names to search; use `_all` or empty string to perform the operation on all indices.
Field substitution (e.g. `index-name-%{date_field}`) is available

[id="plugins-{type}s-{plugin}-password"]
===== `password` 

  * Value type is <<password,password>>
  * There is no default value for this setting.

Basic Auth - password

[id="plugins-{type}s-{plugin}-query"]
===== `query` 

  * Value type is <<string,string>>
  * There is no default value for this setting.

Elasticsearch query string. Read the Elasticsearch query string documentation.
for more info at: https://www.elastic.co/guide/en/elasticsearch/reference/master/query-dsl-query-string-query.html#query-string-syntax

[id="plugins-{type}s-{plugin}-query_template"]
===== `query_template` 

  * Value type is <<string,string>>
  * There is no default value for this setting.

File path to elasticsearch query in DSL format. Read the Elasticsearch query documentation
for more info at: https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl.html

[id="plugins-{type}s-{plugin}-result_size"]
===== `result_size` 

  * Value type is <<number,number>>
  * Default value is `1`

How many results to return

[id="plugins-{type}s-{plugin}-sort"]
===== `sort` 

  * Value type is <<string,string>>
  * Default value is `"@timestamp:desc"`

Comma-delimited list of `<field>:<direction>` pairs that define the sort order

[id="plugins-{type}s-{plugin}-ssl"]
===== `ssl` 

  * Value type is <<boolean,boolean>>
  * Default value is `false`

SSL

[id="plugins-{type}s-{plugin}-tag_on_failure"]
===== `tag_on_failure` 

  * Value type is <<array,array>>
  * Default value is `["_elasticsearch_lookup_failure"]`

Tags the event on failure to look up previous log event information. This can be used in later analysis.

[id="plugins-{type}s-{plugin}-user"]
===== `user` 

  * Value type is <<string,string>>
  * There is no default value for this setting.

Basic Auth - username



[id="plugins-{type}s-{plugin}-common-options"]
include::{include_path}/{type}.asciidoc[]
