OpenSearch/docs/plugins/lang-javascript.asciidoc
Jack Conradson 185dff7346 Cleanup ScriptType (#21179)
Refactored ScriptType to clean up some of the variable and method names. Added more documentation. Deprecated the 'in' ParseField in favor of 'stored' to match the indexed scripts being replaced by stored scripts.
2016-10-31 13:48:51 -07:00

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[[lang-javascript]]
=== JavaScript Language Plugin
deprecated[5.0.0,JavaScript will be replaced by the new scripting language {ref}/modules-scripting-painless.html[`Painless`]]
The JavaScript language plugin enables the use of JavaScript in Elasticsearch
scripts, via Mozilla's
https://developer.mozilla.org/en-US/docs/Mozilla/Projects/Rhino[Rhino JavaScript] engine.
[[lang-javascript-install]]
[float]
==== Installation
This plugin can be installed using the plugin manager:
[source,sh]
----------------------------------------------------------------
sudo bin/elasticsearch-plugin install lang-javascript
----------------------------------------------------------------
The plugin must be installed on every node in the cluster, and each node must
be restarted after installation.
This plugin can be downloaded for <<plugin-management-custom-url,offline install>> from
{plugin_url}/lang-javascript/lang-javascript-{version}.zip.
[[lang-javascript-remove]]
[float]
==== Removal
The plugin can be removed with the following command:
[source,sh]
----------------------------------------------------------------
sudo bin/elasticsearch-plugin remove lang-javascript
----------------------------------------------------------------
The node must be stopped before removing the plugin.
[[lang-javascript-usage]]
==== Using JavaScript in Elasticsearch
Once the plugin has been installed, JavaScript can be used at a scripting
language by setting the `lang` parameter to `javascript`.
Scripting is available in many APIs, but we will use an example with the
`function_score` for demonstration purposes:
[[lang-javascript-inline]]
[float]
=== Inline scripts
WARNING: Enabling inline scripting on an unprotected Elasticsearch cluster is dangerous.
See <<lang-javascript-file>> for a safer option.
If you have enabled {ref}/modules-scripting-security.html#enable-dynamic-scripting[inline scripts],
you can use JavaScript as follows:
[source,js]
----
PUT test/doc/1
{
"num": 1.0
}
PUT test/doc/2
{
"num": 2.0
}
GET test/_search
{
"query": {
"function_score": {
"script_score": {
"script": {
"inline": "doc[\"num\"].value * factor",
"lang": "javascript",
"params": {
"factor": 2
}
}
}
}
}
}
----
// CONSOLE
[[lang-javascript-stored]]
[float]
=== Stored scripts
WARNING: Enabling stored scripts on an unprotected Elasticsearch cluster is dangerous.
See <<lang-javascript-file>> for a safer option.
If you have enabled {ref}/modules-scripting-security.html#enable-dynamic-scripting[stored scripts],
you can use JavaScript as follows:
[source,js]
----
PUT test/doc/1
{
"num": 1.0
}
PUT test/doc/2
{
"num": 2.0
}
POST _scripts/javascript/my_script <1>
{
"script": "doc[\"num\"].value * factor"
}
GET test/_search
{
"query": {
"function_score": {
"script_score": {
"script": {
"stored": "my_script", <2>
"lang": "javascript",
"params": {
"factor": 2
}
}
}
}
}
}
----
// CONSOLE
<1> We store the script under the id `my_script`.
<2> The function score query retrieves the script with id `my_script`.
[[lang-javascript-file]]
[float]
=== File scripts
You can save your scripts to a file in the `config/scripts/` directory on
every node. The `.javascript` file suffix identifies the script as containing
JavaScript:
First, save this file as `config/scripts/my_script.js` on every node
in the cluster:
[source,painless]
----
doc["num"].value * factor
----
then use the script as follows:
[source,js]
----
PUT test/doc/1
{
"num": 1.0
}
PUT test/doc/2
{
"num": 2.0
}
GET test/_search
{
"query": {
"function_score": {
"script_score": {
"script": {
"file": "my_script", <1>
"lang": "javascript",
"params": {
"factor": 2
}
}
}
}
}
}
----
// CONSOLE
<1> The function score query retrieves the script with filename `my_script.javascript`.