Type conversion in elasticsearch scripts

Question

I would like to use a script to do the following:

{
  "query": {
  "match_all": {}
},
  "facets": {
    "user_facet": {
      "terms": {
        "field": "user_id",
        "script": "term + \"_\" + _source.code"
      }
    }
  }
}

This is similar to the answer given in this question: elastic search double facet

The only problem I have is my user_id and code fields are long types, rather than strings. Is there a way to make them strings so they can be combined with the script?

The particular error I am getting is this:

nested: ClassCastException[java.lang.String cannot be cast to java.lang.Number];

Answer 1

This might sound ridiculous, but I had the same issue, and the way I fixed it (for a VERY similar problems) was to drop the "field" specification so that it looks like this:

{
  "query": {
  "match_all": {}
},
  "facets": {
    "user_facet": {
      "terms": {
        "script": "term + \"_\" + _source.code"
      }
    }
  }
}

I think it was trying to convert the output of the "script" execution back into the type of the field, causing the class cast exception.