title: JSONField workaround on elasticsearch : MapperParsingException
body: <p>How can I map Postgres <code>JsonField</code> of  a Django model to ElasticSearch indexing? Is there any workaround to make it work?</p>
  
  <p>Reference : <a href="https://github.com/sabricot/django-elasticsearch-dsl/issues/36" rel="noreferrer">https://github.com/sabricot/django-elasticsearch-dsl/issues/36</a></p>
  
  <ul>
  <li>models.py </li>
  </ul>
  
  <pre><code>class Web_Technology(models.Model):
      web_results = JSONField(blank=True,null=True,default=dict)
  </code></pre>
  
  <ul>
  <li>web_results field format</li>
  </ul>
  
  <pre><code>{"http://google.com": {"Version": "1.0", "Server": "AkamaiGHost"}}
  </code></pre>
  
  <ul>
  <li>documents.py</li>
  </ul>
  
  <pre><code>from elasticsearch_dsl import Index
  from django_elasticsearch_dsl import Document, fields
  from django_elasticsearch_dsl.registries import registry
  
  from .models import Web_Technology
  
  @registry.register_document
  class WebTechDoc(Document):
  
      web_results = fields.ObjectField()
  
      def prepare_web_results(self, instance):
          return instance.web_results
      class Index:
          name = 'webtech'
  
      class Django:
          model = Web_Technology
          fields = []
  
  </code></pre>
  
  <pre><code>`→ python3 manage.py search_index --create -f
  Creating index '&lt;elasticsearch_dsl.index.Index object at 0x7f5f7b07ed30&gt;'
  Traceback (most recent call last):
    File "manage.py", line 15, in &lt;module&gt;
      execute_from_command_line(sys.argv)
    File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 381, in execute_from
  _command_line
      utility.execute()
    File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 375, in execute
      self.fetch_command(subcommand).run_from_argv(self.argv)
    File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 323, in run_from_argv
  C    self.execute(*args, **cmd_options)
    File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 364, in execute
      output = self.handle(*args, **options)
    File "/usr/local/lib/python3.5/dist-packages/django_elasticsearch_dsl/management/commands/search_index.py", line 128, in handle
      self._create(models, options)
    File "/usr/local/lib/python3.5/dist-packages/django_elasticsearch_dsl/management/commands/search_index.py", line 84, in _create
      index.create()
    File "/usr/local/lib/python3.5/dist-packages/elasticsearch_dsl/index.py", line 254, in create
      self._get_connection(using).indices.create(index=self._name, body=self.to_dict(), **kwargs)
    File "/usr/local/lib/python3.5/dist-packages/elasticsearch/client/utils.py", line 84, in _wrapped
      return func(*args, params=params, **kwargs)
    File "/usr/local/lib/python3.5/dist-packages/elasticsearch/client/indices.py", line 105, in create
      "PUT", _make_path(index), params=params, body=body
    File "/usr/local/lib/python3.5/dist-packages/elasticsearch/transport.py", line 350, in perform_request
      timeout=timeout,
    File "/usr/local/lib/python3.5/dist-packages/elasticsearch/connection/http_urllib3.py", line 252, in perform_request
      self._raise_error(response.status, raw_data)
    File "/usr/local/lib/python3.5/dist-packages/elasticsearch/connection/base.py", line 181, in _raise_error
      status_code, error_message, additional_info
  elasticsearch.exceptions.RequestError: RequestError(400, 'MapperParsingException[mapping [properties]]; nested: MapperParsingException[Root type mapping not empty after parsing! Remaining fields:   [web_results : {type=object}]]; ', 'MapperParsingException[mapping [properties]]; nested: MapperParsingException[Root type mapping not empty after parsing! Remaining fields:   [web_results : {type=object}]]; ')
  </code></pre>
  
  <p>If there are none workarounds to make it work, then suggest me a other fast search indexer which supports <code>JsonField</code>.</p>
  
  <blockquote>
    <p>ElasticSearch Logs:</p>
  </blockquote>
  
  <pre><code>[2019-09-10 19:41:22,399][DEBUG][action.admin.indices.create] [cimexnode] [webtech] failed to create
  org.elasticsearch.index.mapper.MapperParsingException: mapping [properties]
          at org.elasticsearch.cluster.metadata.MetaDataCreateIndexService$2.execute(MetaDataCreateIndexService.java:394)
          at org.elasticsearch.cluster.service.InternalClusterService$UpdateTask.run(InternalClusterService.java:374)
          at org.elasticsearch.common.util.concurrent.PrioritizedEsThreadPoolExecutor$TieBreakingPrioritizedRunnable.runAndClean(PrioritizedEsThreadPoolExecutor.java:204)
          at org.elasticsearch.common.util.concurrent.PrioritizedEsThreadPoolExecutor$TieBreakingPrioritizedRunnable.run(PrioritizedEsThreadPoolExecutor.java:167)
          at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
          at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
          at java.lang.Thread.run(Thread.java:748)
  Caused by: org.elasticsearch.index.mapper.MapperParsingException: Root type mapping not empty after parsing! Remaining fields:   [web_results : {type=object}]
          at org.elasticsearch.index.mapper.DocumentMapperParser.parse(DocumentMapperParser.java:278)
          at org.elasticsearch.index.mapper.DocumentMapperParser.parseCompressed(DocumentMapperParser.java:192)
          at org.elasticsearch.index.mapper.MapperService.parse(MapperService.java:449)
          at org.elasticsearch.index.mapper.MapperService.merge(MapperService.java:307)
          at org.elasticsearch.cluster.metadata.MetaDataCreateIndexService$2.execute(MetaDataCreateIndexService.java:391)
          ... 6 more
  </code></pre>