如何利用 Python MongoDB 数据分片实现数据共享和数据交换

from pymongo import MongoClient, errors
from pymongo.errors import ConnectionFailure
import random

# MongoDB 分片集群节点列表
nodes = ["mongodb1.example.com", "mongodb2.example.com", "mongodb3.example.com"]

# 连接 MongoDB 分片集群
def connect():
    try:
        # 随机选择一个节点连接
        client = MongoClient(random.choice(nodes), replicaSet="myreplica")
        return client
    except ConnectionFailure as e:
        print("Failed to connect to MongoDB: %s" % e)
        return None

# 获取 MongoDB 集合
def get_collection(client, db_name, collection_name):
    db = client[db_name]
    collection = db[collection_name]
    return collection

# 创建分片键索引
def create_shard_key_index(collection):
    collection.create_index([("domain", "hashed")])

# 执行分片命令
def shard_collection(collection, shard_key):
    command = {"shardCollection": "%s.%s" % (collection.database.name, collection.name), "key": shard_key}
    result = collection.database.command(command)
    return result

# 插入数据
def insert_data(collection):
    data = {"domain": "pidancode.com", "name": "皮蛋编程", "age": 18}
    collection.insert_one(data)

# 查询数据
def find_data(client, db_name, collection_name):
    collection = get_collection(client, db_name, collection_name)
    data = collection.find_one({"domain": "pidancode.com"})
    return data

# 在两个集合之间复制数据
def copy_data(src_collection, dst_collection):
    data = src_collection.find()
    for d in data:
        dst_collection.insert_one(d)