How to do a wildcard or regex match on _id in elasticsearch?

Question

From below sample elasticsearch data I want to apply wildcard say *.000ANT.* on _id so as to fetch all docs whose _id contains 0

Answer 1

Allow your mapping for the id to be indexed:

{
  "mappings": {
    "agents": {
        "_id": {
        "index": "not_analyzed"
      }
    }
  }
}

And use a query_string to search for it:

{
  "query": {
    "query_string": {
      "query": "_id:(*000ANT*)",
      "lowercase_expanded_terms": false
    }
  }
}

Or like this (with scripts and still querying only the _id):

{
  "query": {
    "filtered": {
      "filter": {
        "script": {
          "script": "org.elasticsearch.index.mapper.Uid.splitUidIntoTypeAndId(new org.apache.lucene.util.BytesRef(doc['_uid'].value))[1].utf8ToString().contains('000ANT')"
        }
      }
    }
  }
}