Celery custom backend fields

celery_tasks.py

celery_app = Celery(
    'celery_tasks',
    broker=BROKER_URL,
    backend='celery_tasks:CustomBackendResult',
    elasticsearch_save_meta_as_text=False,
    result_extended=True,
)

class CustomBackendResult(ElasticsearchBackend):
    def __init__(self, url=None, *args, **kwargs):
        # https://github.com/celery/celery/blob/20b396d6e02c0b91f2e4663d0cd2355f76799c5e/celery/app/backends.py#L68
        super().__init__(url=BACKEND_URL, *args, **kwargs)
    
    def _get_result_meta(self, result, state, traceback, request, format_date=True, encode=False):
        meta = super()._get_result_meta(result, state, traceback, request, format_date=format_date, encode=encode)
        
        if isinstance(result, dict):
            for k,v in result.items():
                meta[k] = v
        
        return meta