なんかよくわからんが, すごい短い間隔でDBをドロップすると, GridFSの部分で失敗する. あとで細かいことを検証しよう.

gistfile1.py

# -*- coding: utf-8

# This code doesn't work correctly.
# Reproduced on Python 2.7, Mongodb 1.8.4, pymongo 2.0.1 and mongoengine 0.5

from mongoengine import Document, FileField, connect
import pymongo

db = 'my_test'

class C(Document):
    f = FileField()

def drop_db():
    con = pymongo.Connection()
    con.drop_database(db)
    return

def test_code():
    c = C()
    c.f = 'data'
    c.save()
    return

if __name__ == "__main__":
    connect(db)

    drop_db()
    test_code()
    drop_db()
    test_code()
    drop_db()