ElasticSearch custom sort, based on provided ids array order. Original code from here: http://damienalexandre.fr/post/elasticsearch-ids-query-order Rewritten to new "function_score" syntax Note: You need to remove \n new lines from "script" field in order to get it work.

elasticsearch.custom.sort.py

q = {
  "query": {
    "function_score": {
      "boost_mode": "replace",
      "query": {
        "ids": {
          "values": [
            50,
            80,
            44,
            12
          ]
        }
      },
      "script_score": {
        "params": {
          "ids": [
              50,
              80,
              44,
              12
          ]
        },
        "script": """
          count = ids.size();
          id    = org.elasticsearch.index.mapper.Uid.idFromUid(doc['_uid'].value);
          for (i = 0; i < count; i++) {
            if (id == ids[i]) { return count - i; }
           }""",
      }
    }
  },
  "size": 20,
  "from": 0
}

"script_score": {
  "params": {
    "ids": [
        50,
        80,
        44,
        12
    ]
  },
  "script": """
    count = ids.size();
    id    = org.elasticsearch.index.mapper.Uid.idFromUid(doc['_uid'].value);
    for (i = 0; i < count; i++) {
      if (id == ids[i]) { return count - i; }
     }""",
}

This doesn't work in my case.

I update it to:

sort: {
  _script: {
    type: 'number',
    script: {
      lang: 'painless',
      params: {
        ids: [4,8,2,4,8,16],
      },
      source: `
        int idsCount = params.ids.size();
        def id = doc['slug.keyword'].value;
        int foundIdx = params.ids.indexOf(id);
        return foundIdx > -1 ? foundIdx: idsCount + 1;
      `
    }
  }
}

hope it helps someone