Using Native Scripts in Elastic Search

native_script_example.txt

1) Extend AbstractFloatSearchScript:

package com.example.elastic;

import org.elasticsearch.script.AbstractFloatSearchScript;

import static java.lang.Math.*;

public class MySearchScript extends AbstractFloatSearchScript {
    @Override
    public float runAsFloat() {
        int daysSinceRelease = doc().numeric("daysSinceRelease").getIntValue();

        return score() + 0.033f * ((float)
                (
                        0.4 * (
                                -150.0 * pow(max(daysSinceRelease - -30000.0, 0), 0.000001) * pow(max(-1826.0 - daysSinceRelease, 0), 0.000001)
                        )
                )

        );
    }
}

2) Extend NativeScriptFactory:

package com.example.elastic;

import org.elasticsearch.common.Nullable;
import org.elasticsearch.script.ExecutableScript;
import org.elasticsearch.script.NativeScriptFactory;

import java.util.Map;

public class MyScriptFactory implements NativeScriptFactory {
    @Override public ExecutableScript newScript(@Nullable Map<String, Object> params) {
        return new MySearchScript();
    }
}

3) Create a jar with the two classes

4) Place jar in $ES_HOME/lib or $ES_HOME/plugins/SOME_NAME

5) Add to $ES_HOME/config/elasticsearch.yml

script.native.foo.type:
  com.example.elastic.MySearchScript

Where foo is the alias for your script.  Name it whatever you want.

6) Issue your custom query e.g.:

curl -XGET 'http://localhost:9200/media/object/_search' -d '{"explain" : true, "query":{"custom_score":{ "query":{ "query_string":{ "fields" : ["title^1.5", "alt_title^0.3", "objectType^0.05"], "use_dis_max": "true", "query":"honda civic" } }, "lang":"native", "script":"foo" } } }'