pymongo 连接MongoDB数据库，分为无权限认证和有权限认证两种。

关于如何设置mongodb权限认证，请见米扑博客： MongoDB 用户认证权限总结

添加用户权限认证

1. 添加用户

root@ubuntu:~/script# mongo
MongoDB shell version: 2.6.4
connecting to: test
> use admin       // 切换到管理员 admin 数据库
switched to db admin
> show collections
system.indexes
system.users
system.version
> db.system.users.count()
1
> db.addUser('admin','123456')     // 在 admin 数据库，添加超级管理员用户 'admin'， 密码'123456'
WARNING: The 'addUser' shell helper is DEPRECATED. Please use 'createUser' instead
Successfully added user: { "user" : "admin", "roles" : [ "root" ] }
> db.system.users.find()
{ "_id" : "db_blog.blog_user", "user" : "blog_user", "db" : "db_blog", "credentials" : { "MONGODB-CR" : "1358889f06fc384a21f0e316ff1750ab" }, "roles" : [ { "role" : "dbOwner", "db" : "db_blog" } ] }
{ "_id" : "admin.admin", "user" : "admin", "db" : "admin", "credentials" : { "MONGODB-CR" : "95ec4261124ba5951720b199908d892b" }, "roles" : [ { "role" : "root", "db" : "admin" } ] }

2. 删除用户

> db.removeUser('admin')
WARNING: db.removeUser has been deprecated, please use db.dropUser instead
true

3. 修改用户

修改用户，就是先删除现有用户，再添加同名用户及密码

方式1: 无用户权限验证

    mongo_conn = None
    try:
        mongo_conn = pymongo.Connection(host, port)
        mongo_db = mongo_conn[db_name]
        mongo_coll = mongo_db[coll_name]
        print("conn_mongo: %d" % mongo_coll.count())
    except Exception as ex:
        print("conn mongo error: " + str(ex))

方式2: 用户权限验证（1）

连接方式：

mongodb://{username}:{password}@{host}:{port}/{db_name}?authMechanism=MONGODB-CR

代码示例：

    uri = "mongodb://{username}:{password}@{host}:{port}/{db_name}?authMechanism=MONGODB-CR".format(username=user_name,
                                                                           password=user_pwd,
                                                                           host=host,
                                                                           port=port,
                                                                           db_name=db_name)
    print("conn_mongo_2 -- uri: " + uri)
    mongo_client = pymongo.MongoClient(uri)
    mongo_db = mongo_client[db_name]
    mongo_coll = mongo_db[coll_name]
    print("conn_mongo_2 -- count: %d" % mongo_coll.count())

方式3: 用户权限验证（2） 

连接方式：

    mongo_client = pymongo.MongoClient("%s:%d"%(host, port))
    mongo_client[db_name].authenticate(user_name, user_pwd, db_name, mechanism='MONGODB-CR')

代码示例：

    mongo_client = pymongo.MongoClient("%s:%d"%(host, port))
    mongo_client[db_name].authenticate(user_name, user_pwd, db_name, mechanism='MONGODB-CR')
    mongo_db = mongo_client[db_name]
    mongo_coll = mongo_db[coll_name]
    print("conn_mongo_3 -- count: %d" % mongo_coll.count())

完整示例：

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# PyMongo Authentication Examples
# http://api.mongodb.org/python/current/examples/authentication.html

import pymongo

host = '127.0.0.1'
port = 27017
user_name = 'mimvp'
user_pwd = '123456'
db_name = 'mimvp_blog'
coll_name = 'blog_coll'


def conn_mongo():
    '''
    host:port
    no authenticate
    '''
    mongo_conn = None
    try:
        mongo_conn = pymongo.Connection(host, port)
        mongo_db = mongo_conn[db_name]
        mongo_coll = mongo_db[coll_name]
        print("conn_mongo: %d" % mongo_coll.count())
    except Exception as ex:
        print("conn mongo error: " + str(ex))
    

def conn_mongo_2():
    '''
    mongodb://username:password@host:port/dbname
    '''
    uri = "mongodb://{username}:{password}@{host}:{port}/{db_name}?authMechanism=MONGODB-CR".format(username=user_name,
                                                                           password=user_pwd,
                                                                           host=host,
                                                                           port=port,
                                                                           db_name=db_name)
    print("conn_mongo_2 -- uri: " + uri)
    mongo_client = pymongo.MongoClient(uri)
    mongo_db = mongo_client[db_name]
    mongo_coll = mongo_db[coll_name]
    print("conn_mongo_2 -- count: %d" % mongo_coll.count())
    
    
def conn_mongo_3():
    '''
    host:port
    client.authenticate(username, password)
    '''
    mongo_client = pymongo.MongoClient("%s:%d"%(host, port))
    mongo_client[db_name].authenticate(user_name, user_pwd, db_name, mechanism='MONGODB-CR')
    mongo_db = mongo_client[db_name]
    mongo_coll = mongo_db[coll_name]
    print("conn_mongo_3 -- count: %d" % mongo_coll.count())
    

if __name__ == '__main__':
    conn_mongo()
    conn_mongo_2()
    conn_mongo_3()

运行结果：

conn_mongo: 33
conn_mongo_2 -- uri: mongodb://youku:123456@127.0.0.1:27017/youku_source_center?authMechanism=MONGODB-CR
conn_mongo_2 -- count: 33
conn_mongo_3 -- count: 33

参考推荐：

pymongo 使用测试

PyMongo Authentication Examples（官方）

MongoDB 用户认证权限总结