Getting field names

TL;DR: Is there any “simple” way to get document field names?

Despite ES being schemaless, I believe that many people works with ES respecting schema (which is pretty natural, as we can use object mapping). Personally, I try to verify any data on app side, to avoid implicit mapping, which can lead to troubles in future indexing/migrations. And as ES have no “constraints” against dynamic mapping and elasticsearch-dsl-py allows to save docs via DocType(**data) unpacking, I’ve extended DocType with

@classmethod
    def get_field_names(cls, path=None):
        if path is None:
            return cls._doc_type.mapping.properties.properties._d_.keys()
        else:
            getter = attrgetter('.'.join('{}.properties'.format(f) for f in path.split('.') if f))
            try:
                return getter(cls._doc_type.mapping.properties.properties)._d_.keys()
            except AttributeError:
                return []

which acts like Django’s get_all_field_names, but also allows to get field names for Nested and Object fields. Is there a simpler way, or such usecase is pretty rare? Thx.

[honzakral]

ES isn’t really schema-less, that is a common misconception based on it having a dynamic schema. It does have one. Also it has constraints against dynamic mapping - you can set dynamic to false (causing es to ignore unmapped fields) or you can set it to strict (causing ES to raise an error on encountering unmapped field) [0]. This made me realize that we don’t have a way to set this in the python dsl (created #146 to track.)

With that information I don’t think we need a get_field_by_name, or get_fields. But if you think it would be useful and others agree we can definitely add these method to DocTypeOptions where I think these should live.

Does this make sense?

Thanks

0 - http://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-dynamic-mapping.html

[honzakral]

This has been resolved by e1bf242