Elasticsearch: ExpressionScriptEngineService not available when running embedded

[hendrikdonvil]

When running Elasticsearch embedded in Java, I cannot use scripts of language 'expression'. I'm getting these errors:
script_score the script could not be loaded]; nested: ElasticsearchIllegalArgumentException[script_lang not supported [expression]];
Debugging shows that the ExpressionScriptEngineService is not injected into the ScriptEngine.

Running the exact same query on a standalone elasticsearch runs fine.

I'm using 1.5.2, but tested also on 1.6.0, with the same behaviour.

[s1monw]

the expression lib is marked as optional in the pom

 <dependency>
            <groupId>org.apache.lucene</groupId>
            <artifactId>lucene-expressions</artifactId>
            <version>${lucene.maven.version}</version>
            <scope>compile</scope>
            <optional>true</optional>
        </dependency>

if you pull it in manually does this fix it?

[hendrikdonvil]

This fixes it! Thanks a lot!

Just a little annoying that we have to keep this version in sync with the version elasticsearch uses, if we upgrade in the future, but that's not that big a deal.

[s1monw]

cool thanks

[synhershko]

What is the up-to-date guidance here, now that lang-expression is it's own module? Including both org.elasticsearch.lang-expression and org.apache.lucene.lucene-expressions as dependencies doesn't seem to work.

[synhershko]

Ok, figured it out :)

For the future reader - make sure you include both lang-expression from org.elasticsearch.module and the lucene package mentioned above; and then add ExpressionPlugin.class to nodePlugins in your InternalCluster configs

[statut]

@synhershko could you, please, explain where InternalCluster configs are located and how to add ExpressionPlugin.class? Thanks.

[synhershko]

InternalCluster configs are located in one of the methods in the class where the cluster is initialized