在Python中连接MongoDB集群(MongoDB Cluster)

忘是亡心i 2022-01-31 11:57 798阅读 0赞

建立了一个MongoDB集群，集群名称 replSet=rs0，包含以下 3 个节点：

172.16.250.233:27017 # SECONDARY
    172.16.250.234:27017 # PRIMARY
    172.16.250.237:27017 # SECONDARY

集群的 test 用户的密码为 “123456” ，只能访问 test 数据库。

另外还有一个MongoDB数据库单独部署在 172.16.250.238，其 admin 用户的密码为 “123456” ，只能访问 admin 数据库。

MongoDB集群没有提供类似MySQL集群和Redis集群中的虚拟IP。在使用的时候需要客户端连接时指定MongoDB集群的所有节点。

Python连接MongoDB的驱动为pymongo, 基于pymongo 有封装的mongoengine,以及基于mongoengine 的 flask\_mongoengie。

具体写法如下：

## pymongo ##

# coding=utf-8
    
    from pymongo import MongoClient
    
    # single mongo
    c = MongoClient(host="172.16.250.238", port=27017) # ret : ['admin', 'config', 'local']
    # c = MongoClient(host="mongodb://172.16.250.238:27017") # ret : ['admin', 'config', 'local']
    # c = MongoClient(host="mongodb://admin:123456@172.16.250.238:27017") # ret : ['admin', 'config', 'local']
    # c = MongoClient(host="mongodb://admin:123456@172.16.250.238:27017/admin") # ret : ['admin', 'config', 'local']
    
    # mongo cluster
    # c = MongoClient('mongodb://test:123456@172.16.250.233:27017,172.16.250.234:27017,172.16.250.237:27017/test') # ret : ['test']
    # c = MongoClient('mongodb://test:123456@172.16.250.233:27017,172.16.250.234:27017,172.16.250.237:27017/test?replicaSet=rs0') # ret : ['test']
    # c = MongoClient('mongodb://test:123456@172.16.250.233:27017,172.16.250.234:27017,172.16.250.237:27017/test?readPreference=secondary') # ret : ['test']
    
    print(c.list_database_names())

## mongoengine ##

# coding=utf-8
    
    from mongoengine import connect
    from mongoengine import Document
    from mongoengine import StringField
    
    # single mongo
    connect('admin', host='mongodb://admin:123456@172.16.250.238:27017')
    
    # mongo cluster
    # connect('test', host='mongodb://test:123456@172.16.250.233:27017,172.16.250.234:27017,172.16.250.237:27017/test?readPreference=secondary')
    
    
    class User(Document): # 类名需要与数据库中的集合名称一致
        name = StringField(required=True, max_length=200)
    
    users = User.objects.all() #返回所有的文档对象列表
    
    for u in users:
        print("name:",u.name)

## flask\_mongoengine ##

# coding=utf-8
    from flask_mongoengine import MongoEngine
    from flask import Flask
    
    app = Flask(__name__)
    
    # app.config['MONGODB_SETTINGS'] = {
    #         'host': 'mongodb://admin:123456@172.16.250.238:27017/admin',
    #         }
    
    # app.config.from_pyfile('mongo.cfg')
    
    # app.config['MONGODB_SETTINGS'] = {
    #        'db': 'admin',
    #        'username': 'admin',
    #        'password': '123456',
    #        'host': '172.16.250.238',
    #        'port': 27017
    #        }
    
    app.config['MONGODB_SETTINGS'] = [
        {
            'db': 'test',
            'username': 'test',
            'password': '123456',
            'host': '172.16.250.233',
            'port': 27017
        },
        {
            'db': 'test',
            'username': 'test',
            'password': '123456',
            'host': '172.16.250.234',
            'port': 27017
        }, {
            'db': 'test',
            'username': 'test',
            'password': '123456',
            'host': '172.16.250.237',
            'port': 27017
        }
    ]
    
    db = MongoEngine(app)
    
    
    class User(db.Document):
        name = db.StringField(required=True, max_length=50)
    
    
    users = User.objects.all()  # 返回所有的文档对象列表
    
    for u in users:
        print("name:", u.name)

配置文件 mongo.cfg 格式如下：

MONGODB_SETTINGS = {
                       'host': 'mongodb://admin:123456@172.16.250.238:27017/admin',
                       }

原文地址：[https://www.jianshu.com/p/a0a23443146e][https_www.jianshu.com_p_a0a23443146e]

[https_www.jianshu.com_p_a0a23443146e]: https://www.jianshu.com/p/a0a23443146e