PyMongo/Mongoengine equivalent of mongodump

The accepted answer is not working anymore. Here is a revised code:

from os.path import join
import pymongo
from bson.json_util import dumps

def backup_db(backup_db_dir):
    client = pymongo.MongoClient(host=..., port=..., username=..., password=...)
    database = client[<db_name>]
    collections = database.collection_names()

    for i, collection_name in enumerate(collections):
        col = getattr(database,collections[i])
        collection = col.find()
        jsonpath = collection_name + ".json"
        jsonpath = join(backup_db_dir, jsonpath)
        with open(jsonpath, 'wb') as jsonfile:
            jsonfile.write(dumps(collection).encode())


backup_db('.')

For my relatively small small database, I eventually used the following solution. It's not really suitable for big or complex databases, but it suffices for my case. It dumps all documents as a json to the backup directory. It's clunky, but it does not rely on other stuff than pymongo.

from os.path import join
import pymongo
from bson.json_utils import dumps

def backup_db(backup_db_dir):
    client = pymongo.MongoClient(host=<host>, port=<port>)
    database = client[<db_name>]
    authenticated = database.authenticate(<uname>,<pwd>)
    assert authenticated, "Could not authenticate to database!"
    collections = database.collection_names()
    for i, collection_name in enumerate(collections):
        col = getattr(database,collections[i])
        collection = col.find()
        jsonpath = collection_name + ".json"
        jsonpath = join(backup_db_dir, jsonpath)
        with open(jsonpath, 'wb') as jsonfile:
            jsonfile.write(dumps(collection))