dynamic mapping to discard temporary fields after logstash processing

dynamic-mapping.json

{
  "mappings": {
    "logs": {
      "dynamic": "false",
      "_source": {
        "excludes": [
          "*_"
        ]
      },
      "properties": {
        "title": {
          "type": "string"
        },
        "str": {
          "type": "string",
          "index": "not_analyzed",
          "doc_values": true,
          "fields": {
            "analyzed": {
              "type": "string",
              "index": "analyzed"
            }
          }
        }
      },
      "dynamic_templates": [
        {
          "discard": {
            "match": "*_",
            "mapping": {
              "index": "no"
            }
          }
        }
      ]
    }
  }
}