Elasticsearch Series (vii) Java definition Score

Overview

ES supports groovy and Java two language custom score calculations, groovy can even be nested in the requested parameters, a little bit, but not in the scope of this discussion.

How to use custom Java code to define how score is generated, which uses the ES plugin function

For more information about the ES plugin, you can use the following command to obtain

./bin elasticsearch-plugn–h

Action Step 1. Add configuration

First you need to add the following in the ES configuration,

The old version is

False

The currently used ES is 5.2.2, according to the log prompt, changed to the following, after the change to restart ES

Script.inline:truescript.stored:true

I have to say, this log provides a good message.

If you do not add these two configurations, this error

2. Write Java code

Java Code Format Reference

Https://www.elastic.co/guide/en/elasticsearch/reference/5.2/modules-scripting-native.html

3. Write the configuration file

Configuration file Format Reference

Https://github.com/elastic/elasticsearch/blob/master/buildSrc/src/main/resources/plugin-descriptor.properties

4. Uploading to the ES cluster

Create a new folder in $elasticsearch_home/plugins, the name of this folder is the name of the plugin,

For example, there are three of folders

You can find them by following the command

In the new folder, import the jar Package and the plugin-descriptor.properties file (must have)

5. Restart the ES service

Kill-9 PID

Nohup./elasticsearch &

5. Use

{  "query":    {"Function_score"      : {"Query           "        : {"Match": { "Your_fields": "xxxx"        }      ,      "Functions": [        {          "Script_score": {            "Script":{              "inline": "Key",              "lang": "Native",              "params" : {                "your_fields": "xxxxx"              }   }}}}}}

Key explanation:

Key	Explain	Note
Inline	Call the plugin's key, and the plugin name is two things	In the Nativescriptfactory interface, the GetName () method settings
Lang	Custom mode	Native meaning is implemented with Java native

About customizing Function-script-score

Https://www.elastic.co/guide/en/elasticsearch/reference/5.2/query-dsl-function-score-query.html#function-script-score

6. Updating plugins

Because ES cluster will cache plug-in code, even if the plugin is still available to delete, still need to restart to update the plugin

Resources

Steps necessary to customize the Java authoring plugin

Https://www.elastic.co/guide/en/elasticsearch/plugins/5.2/plugin-authors.html#_plugin_structure

GitHub Full Plugin

Https://github.com/momoxixi/elasticsearch-feature-vector-scoring

Elasticsearch Series (vii) Java definition Score