58 lines
1.9 KiB
Plaintext
58 lines
1.9 KiB
Plaintext
[[modules-scripting-engine]]
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=== Advanced scripts using script engines
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A `ScriptEngine` is a backend for implementing a scripting language. It may also
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be used to write scripts that need to use advanced internals of scripting. For example,
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a script that wants to use term frequencies while scoring.
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The plugin {plugins}/plugin-authors.html[documentation] has more information on
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how to write a plugin so that Elasticsearch will properly load it. To register
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the `ScriptEngine`, your plugin should implement the `ScriptPlugin` interface
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and override the `getScriptEngine(Settings settings)` method.
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The following is an example of a custom `ScriptEngine` which uses the language
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name `expert_scripts`. It implements a single script called `pure_df` which
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may be used as a search script to override each document's score as
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the document frequency of a provided term.
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["source","java",subs="attributes,callouts,macros"]
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--------------------------------------------------
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include-tagged::{plugins-examples-dir}/script-expert-scoring/src/main/java/org/elasticsearch/example/expertscript/ExpertScriptPlugin.java[expert_engine]
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--------------------------------------------------
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You can execute the script by specifying its `lang` as `expert_scripts`, and the name
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of the script as the script source:
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[source,js]
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--------------------------------------------------
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POST /_search
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{
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"query": {
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"function_score": {
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"query": {
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"match": {
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"body": "foo"
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}
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},
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"functions": [
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{
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"script_score": {
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"script": {
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"source": "pure_df",
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"lang" : "expert_scripts",
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"params": {
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"field": "body",
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"term": "foo"
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}
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}
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}
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}
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]
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}
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}
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}
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--------------------------------------------------
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// CONSOLE
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// TEST[skip:we don't have an expert script plugin installed to test this]
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