# myapp/backends.py
from django.contrib.auth.backends import BaseBackend
from django.contrib.auth.models import User

class ElasticsearchBackend(BaseBackend):
    def authenticate(self, request, username=None, password=None):
        # Query ES here as you're already doing
        if es_auth_valid(username, password):
            user, _ = User.objects.get_or_create(username=username)
            return user
        return None

    def get_user(self, user_id):
        try:
            return User.objects.get(pk=user_id)
        except User.DoesNotExist:
            return None