使用Python构建微服务

2023-12-30 11:22:00

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本文旨在概述基于微服务的架构的基础知识，并学习如何使用 Python 构建微服务。

什么是基于微服务的架构？

? 它是一种架构风格，将复杂的软件系统构建为一组松散耦合的服务，并通过预定义的标准(API)? ? 相互通信。这种架构风格具有敏捷性、可扩展性以及适应不断变化的业务需求的能力等优点。

单体架构和微服务架构之间的区别？

微服务

微服务与单体服务之间的区别

入门

? 我们将通过构建一个允许用户下订单和查看订单的应用程序（DealBazaar）来创建一个简单的? ? ? 项目。所以我们将有 4 项服务，即:

Portal Service——仅渲染 html 内容并将 api 路由到其他服务的服务（该服务不连接到任何数据库）
产品管理——允许创建和检索产品的服务
订单管理——允许创建和检索订单的服务
通知网关 — 允许发送通知（电子邮件）的服务

交易集市

产品管理

产品管理 API 和模型

订单管理

订单管理 API 和模型

通知网关

通知网关 API 和模型

门户服务

门户服务 API

GET / home 和 GET /viewOrder API 只是渲染 html 页面，而不调用其他服务。

获取/订单API

发布/订单API

发布/查看订单 API

1. 设置-安装和下载

下载couchbase?服务器?社区?版本。下载后，创建一个包含 3 个新存储桶和 3 个用户的新集群。提供您选择的存储桶名称和用户名，并在.env文件中使用相同的名称（存储桶名称、用户名和密码）。就我而言——

Couchbase 设置详细信息

登录/注册
网站并生成 API 密钥和 API 密钥。同样将用于发送邮件邮寄订单提交。替换通知网关服务的?.env?文件中的值
安装flask、mailjet_rest、couchbase、load_dotenv、flask-restx

2. 代码

cb.py?- 所有数据库操作的脚本并且对所有服务通用

from couchbase.auth import PasswordAuthenticator
from couchbase.cluster import Cluster
from couchbase.diagnostics import PingState
from couchbase.exceptions import (
    CouchbaseException,
    DocumentExistsException,
    DocumentNotFoundException,
)
from couchbase.options import ClusterOptions

class CouchbaseClient(object):
    def __init__(self, host, bucket, scope, collection, username, pw):
        self.host = host
        self.bucket_name = bucket
        self.collection_name = collection
        self.scope_name = scope
        self.username = username
        self.password = pw

    def connect(self, **kwargs):

        conn_str = f"couchbase://{self.host}"
        try:
            cluster_opts = ClusterOptions( authenticator=PasswordAuthenticator(self.username, self.password) )
            self._cluster = Cluster(conn_str, cluster_opts, **kwargs)
        except CouchbaseException as error:
            print(f"Could not connect to cluster. Error: {error}")
            raise
        self._bucket = self._cluster.bucket(self.bucket_name)
        self._collection = self._bucket.scope(self.scope_name).collection(self.collection_name)

    def get(self, key):
        return self._collection.get(key)

    def insert(self, key, doc):
        return self._collection.insert(key, doc)

    def upsert(self, key, doc):
        return self._collection.upsert(key, doc)

    def remove(self, key):
        return self._collection.remove(key)

    def query(self, strQuery, *options, **kwargs):
        return self._cluster.query(strQuery, *options, **kwargs)

CB.py

app.py?- 产品管理

import os
import uuid
from datetime import datetime
from dotenv import load_dotenv,find_dotenv
from couchbase.exceptions import (
    CouchbaseException,
    DocumentExistsException,
    DocumentNotFoundException,
)
from src.cb import CouchbaseClient
from flask import Flask, request, jsonify
from flask_restx import Api, Resource, fields

app = Flask(__name__)

env_path = "./src/.env"
load_dotenv(env_path)

api = Api(app)
nsProduct = api.namespace("api/v1/products", "CRUD operations for Product")

productInsert = api.model(
    "ProductInsert",
    {
        "productName": fields.String(required=True, description="Product Name"),
        "productId": fields.String(required=True, description="Product's Unique ID"),
        "price": fields.Float(required=True, description="Product Price"),
        "tax": fields.Float(required=True, description="Product tax percentage"),
        "description": fields.String(required=False, description="Description of product"),
        "status": fields.String(required=True, description="Product Status"),
        "url" : fields.String(required=True, description="Image Url of the Product")
    },
)

product = api.model(
    "Product",
    {
        "id": fields.String(required=True, description="Product's system generated Id"),
        "productName": fields.String(required=True, description="Product Name"),
        "productId": fields.String(required=True, description="Product's Unique ID"),
        "price": fields.Float(required=True, description="Product Price"),
        "tax": fields.Float(required=True, description="Product tax percentage"),
        "description": fields.String(required=False, description="Description of product"),
        "status": fields.String(required=True, description="Product Status"),
        "url" : fields.String(required=True, description="Image Url of the Product"),
        "createdAt" : fields.String(required=True, description="Time product is created")
    },
)

@nsProduct.route("")
class Products(Resource):
    # tag::post[]
    @nsProduct.doc(
        "Create Product",
        reponses={201: "Created", 409: "Key alreay exists", 500: "Unexpected Error"},
    )
    @nsProduct.expect(productInsert, validate=True)
    @nsProduct.marshal_with(product)
    def post(self):
        try:
            data = request.json
            id = uuid.uuid4().__str__()
            data["id"] = id
            data["createdAt"] = datetime.now().strftime("%d/%m/%Y %H:%M:%S")
            cb.insert(id, data)
            return data, 201
        except DocumentExistsException:
            return "Key already exists", 409
        except CouchbaseException as e:
            return f"Unexpected error: {e}", 500
        except Exception as e:
            return f"Unexpected error: {e}", 500

    @nsProduct.doc(
        "Find Products",
        reponses={200: "found", 500: "Unexpected Error"},
        params={
            "status": "Product is ACTIVE/INACTIVE"
        },
    )
    def get(self):
        try:
            status = request.args.get("status","ACTIVE")
            query = f"SELECT p.* FROM  {db_info['bucket']}.{db_info['scope']}.{db_info['collection']} p  WHERE p.status = $status;"
            result = cb.query(query, status=status)
            products = [x for x in result]
            return products, 200
        except Exception as e:
            return f"Unexpected error: {e}", 500

@nsProduct.route("/<productId>")
class ProductId(Resource):
    @nsProduct.doc(
        "Get Profile",
        reponses={200: "Document Found", 404: "Document Not Found", 500: "Unexpected Error"},
    )
    def get(self, productId):
        try:
            query = f"SELECT p.* FROM  {db_info['bucket']}.{db_info['scope']}.{db_info['collection']} p  WHERE p.productId = $productId limit 1;"
            result = cb.query(query,productId=productId)
            return list(result)[0] ,200
        except DocumentNotFoundException:
            return "Key not found", 404
        except CouchbaseException as e:
            return f"Unexpected error: {e}", 500

db_info = {
    "host": os.getenv("DB_HOST"),
    "bucket": os.getenv("BUCKET"),
    "scope": os.getenv("SCOPE"),
    "collection": os.getenv("COLLECTION"),
    "username": os.getenv("USERNAME"),
    "password": os.getenv("PASSWORD"),
}

cb = CouchbaseClient(*db_info.values())
cb.connect()

if __name__ == "__main__":
    app.run(debug=True,port=5002)

app.py-产品管理

app.py?- 通知网关

import os
import uuid
from datetime import datetime
from dotenv import load_dotenv
from couchbase.exceptions import DocumentExistsException
from src.cb import CouchbaseClient
from flask import Flask, request
from flask_restx import Api, Resource, fields

from mailjet_rest import Client

app = Flask(__name__)

env_path = "./src/.env"
load_dotenv(env_path)

senderMail = os.getenv("SENDER_MAIL")
mailjet = Client(auth=(os.getenv("API_KEY"), os.getenv("API_SECRET")), version='v3.1')
api = Api(app)
nsProduct = api.namespace("api/v1/email", "Send Email")

emailInsert = api.model(
    "emailInsert",
    {
        "orderId": fields.String(required=True, description="Order ID"),
        "name": fields.String(required=True, description="Name of Customer"),
        "mailId": fields.String(required=True, description="Mail Id of customer"),
        "totalCost" : fields.Float(required=True, description="Total cost of order"),
    },
)

emailResponse = api.model(
    "emailResponse",
    {
        "id": fields.String(required=True, description="Audit for email sent"),
        "orderId": fields.String(required=True, description="Order ID"),
        "mailId": fields.String(required=True, description="Mail Id of customer"),
        "status" : fields.String(required=True, description="Email Status"),
        "deliveredAt" : fields.String(required=True, description="Time email is delivered"),
        "statusCode" : fields.Integer(required=True, description="Status code of SMTP")
    },
)


@nsProduct.route("/sendMail")
class Email(Resource):
    # tag::post[]
    @nsProduct.doc(
        "Send Email",
        reponses={200: "Success", 500: "Unexpected Error"},
    )
    @nsProduct.expect(emailInsert, validate=True)
    @nsProduct.marshal_with(emailResponse)
    def post(self):
        reqData = request.json
        print(reqData)
        data = {
                'Messages': [
                    {
                        "From": {
                            "Email": senderMail,
                            "Name": senderMail
                        },
                        "To": [
                            {
                                "Email": reqData["mailId"],
                                "Name": reqData["name"]
                            }
                        ],
                        "Subject": "Greetings from DealBazaar",
                        "TextPart": f"Your Order {reqData['orderId']} successfully placed !",
                        "HTMLPart": f"<h3>Dear {reqData['name']} , Your order {reqData['orderId']} is successfully placed and the total amount of the order is {reqData['totalCost']} .Thank you for shopping with DealBazaar!"
                    }
                ]
            }
        response = {}
        rep = mailjet.send.create(data=data)
        if rep.status_code==200:
            response["status"] = "SUCCESS"
            response["deliveredAt"] = datetime.now().strftime("%d/%m/%Y %H:%M:%S")
        else:
            response["status"] = "FAILURE"
            response["deliveredAt"] = None
        id = uuid.uuid4().__str__()
        response["id"] = id
        response["mailId"] = reqData["mailId"]
        response["orderId"] = reqData["orderId"]
        response["statusCode"] = rep.status_code
        try :
            cb.insert(id, response)
            return response, 202
        except DocumentExistsException:
            return "Key already exists", 409
        except Exception as e:
            return f"Unexpected error: {e}", 500

db_info = {
    "host": os.getenv("DB_HOST"),
    "bucket": os.getenv("BUCKET"),
    "scope": os.getenv("SCOPE"),
    "collection": os.getenv("COLLECTION"),
    "username": os.getenv("USERNAME"),
    "password": os.getenv("PASSWORD")
}

cb = CouchbaseClient(*db_info.values())
cb.connect()

if __name__ == "__main__":
    app.run(debug=True,port=5004)

app.py-通知网关

app.py?- 订单管理

import os
import uuid
import requests
from datetime import datetime
from dotenv import load_dotenv
from couchbase.exceptions import (
    CouchbaseException,
    DocumentExistsException,
    DocumentNotFoundException,
)
from src.cb import CouchbaseClient
from flask import Flask, request
from flask_restx import Api, Resource, fields

app = Flask(__name__)

env_path = "./src/.env"
load_dotenv(env_path)

api = Api(app)
nsOrder = api.namespace("api/v1/orders", "CRUD operations for Orders")

contact = api.model(
    "Contact",
    {
        "name": fields.String(required=True, description="Customer Name"),
        "emailId": fields.String(required=True, description="emailId of customer"),
        "phone": fields.String(required=True, description="Phone number of customer"),
        "address": fields.String(required=True, description="Address of customer")
    },
)

product = api.model(
    "Product",
    {
        "productName": fields.String(required=True, description="Product Name"),
        "productId": fields.String(required=True, description="Product's Unique ID"),
        "price": fields.Float(required=True, description="Product Price"),
        "tax": fields.Float(required=True, description="Product tax percentage"),
        "quantity" : fields.Integer(required=True,description="Item count")
    },
)

orderInsert = api.model(
    "orderInsert",
    {
        "orderItems": fields.List(fields.Nested(product)),
        "contact": fields.Nested(contact)
    },
)

order = api.model(
    "Order",
    {
        "id": fields.String(required=True, description="Product's system generated Id"),
        "orderId": fields.String(required=True, description="Order Id"),
        "orderItems": fields.List(fields.Nested(product)),
        "contact": fields.Nested(contact),
        "totalCost": fields.Float(required=True, description="Total cost of order"),
        "submittedAt" : fields.String(required=True, description="Time order is submitted"),
    },
)

@nsOrder.route("/submitOrder")
class Orders(Resource):
    
    @nsOrder.doc(
        "Create Product",
        reponses={200: "Success", 409: "Key alreay exists", 500: "Unexpected Error"},
    )
    @nsOrder.expect(orderInsert, validate=True)
    @nsOrder.marshal_with(order)
    def post(self):
        try:
            data = request.json
            print(data)
            data["id"] = uuid.uuid4().__str__()
            data["submittedAt"] = datetime.now().strftime("%d/%m/%Y %H:%M:%S")
            orderId = cb.get(os.getenv("ORDERID_KEY"))
            cb.upsert( os.getenv("ORDERID_KEY"), orderId.value+1)
            orderId = "ORD-"+str(orderId.value)
            data["orderId"] = orderId
            totalCost=0
            for cost in data["orderItems"]:
                totalCost += (cost["price"] * cost["quantity"]) + (cost["price"] * (cost["tax"])/100) * cost["quantity"]
            data["totalCost"] = totalCost
            cb.insert(orderId, data)
            requestData={}
            requestData["orderId"] = data["orderId"]
            requestData["name"] = data["contact"]["name"]
            requestData["mailId"] = data["contact"]["emailId"]
            requestData["totalCost"] = data["totalCost"]
            url = "http://"+os.getenv("NG_BASEURL")+":"+os.getenv("NG_PORT")+os.getenv("NG_URL")
            response = requests.post(url,json=requestData)
            return data, 200
        except DocumentExistsException:
            return "Key already exists", 409
        except CouchbaseException as e:
            return f"Unexpected error: {e}", 500
        except Exception as e:
            return f"Unexpected error: {e}", 500

@nsOrder.route("/<orderId>")
class ProductId(Resource):
    @nsOrder.doc(
        "Get Profile",
        reponses={200: "Document Found", 404: "Document Not Found", 500: "Unexpected Error"},
    )
    def get(self, orderId):
        try:
            result = cb.get(orderId)
            return result.value ,200
        except DocumentNotFoundException:
            return "Key not found", 404
        except CouchbaseException as e:
            return f"Unexpected error: {e}", 500

db_info = {
    "host": os.getenv("DB_HOST"),
    "bucket": os.getenv("BUCKET"),
    "scope": os.getenv("SCOPE"),
    "collection": os.getenv("COLLECTION"),
    "username": os.getenv("USERNAME"),
    "password": os.getenv("PASSWORD"),
}

cb = CouchbaseClient(*db_info.values())
cb.connect()
try:
   cb.get(os.getenv("ORDERID_KEY"))
except DocumentNotFoundException:
    cb.insert(os.getenv("ORDERID_KEY"),int(os.getenv("ORDERID_BASE")))

if __name__ == "__main__":
    app.run(debug=True,port=5003)

app.py-订单管理

app.py?- 门户服务

import os
from dotenv import load_dotenv
import requests
from flask import Flask, request, jsonify,render_template

app = Flask(__name__)

env_path = "./src/.env"
load_dotenv(env_path)


@app.route('/')
@app.route('/home')
def home():
    return render_template('home.html')


@app.route('/order',methods=['GET','POST'])
def order():
    url = "http://" + os.getenv("PM_BASEURL") + ":" + os.getenv("PM_PORT") + os.getenv("PM_GETPRODUCT_URL")
    response = requests.get(url).json()
    if request.method == 'POST':
        data={}
        orderItems = []
        contact = {}
        for item in response:
            orderItem ={}
            if int(request.form[item['productId']]):
                orderItem["quantity"] = int(request.form[item['productId']])
                orderItem["productName"] = item["productName"]
                orderItem["price"] = item["price"]
                orderItem["productId"] = item["productId"]
                orderItem["tax"] = item["tax"]
                orderItems.append(orderItem)

        contact["name"] = request.form["name"]
        contact["address"] = request.form["address"]
        contact["emailId"] = request.form["email"]
        contact["phone"] = request.form["mobile"]
        data["orderItems"] = orderItems
        data["contact"] = contact

        url = "http://" + os.getenv("OM_BASEURL") + ":" + os.getenv("OM_PORT") + os.getenv("OM_SUBMITORDER_URL")
        response = requests.post(url, json=data)
        return render_template('orderView.html',data=response.json())
    return render_template('order.html',data=response)

@app.route('/viewOrder',methods=['GET','POST'])
def viewOrder():
    if request.method == 'POST':
        orderId = request.form['orderId']
        url = "http://" + os.getenv("OM_BASEURL") + ":" + os.getenv("OM_PORT") + os.getenv("OM_GETORDER_URL") + orderId
        response = requests.get(url).json()
        return render_template('orderView.html',data=response)
    return render_template('view.html')

if __name__ == "__main__":
    app.run(debug=True,port=5001)

app.py-门户服务

3. 运行

? 确保您在不同的端口上运行每个服务。就我而言:

服务及其运行的端口

使用以下命令运行每个服务

python app.py

打开终端并通过执行以下curl创建一些产品

curl -H 'Content-Type: application/json' -d '{ "productName":"Neutron Gen Track","productId":"DV0001", "price": 15000 , "tax" : 10 , "url" : "https://media.istockphoto.com/id/1342734683/photo/an-accessory-for-men.jpg?s=612x612&w=0&k=20&c=KRrVxbNC34_dGQZmB7GmihvTB3OSIz2oKNs5RLrlsBQ=" , "status": "ACTIVE" ,"description" : "With New 5003 Designer Analog Watch"}' -X POST http://localhost:5002/api/v1/products

curl -H 'Content-Type: application/json' -d '{ "productName":"Proton Gen Track","productId":"DV0002", "price": 10000 , "tax" : 10 , "url" : "https://images.unsplash.com/photo-1523170335258-f5ed11844a49?q=80&w=2380&auto=format&fit=crop&ixlib=rb-4.0.3&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D" , "status": "ACTIVE" , "description" : "With New 5003 Designer Analog Watch"}' -X POST http://localhost:5002/api/v1/products

用于产品创建的 Curl 执行

打开任意浏览器并输入http:://127.0.0.1:5001/。将呈现 DealBazaar 的主页。

首页-DealBazaar

3. 健全性测试

提交订单- 点击主页中的“立即订购”按钮，选择产品、数量，填写详细信息（姓名、地址、电子邮件电话），然后点击“提交”按钮

提交订单

订单提交结果

查看订单-点击首页查看订单按钮，输入订单Id，点击搜索按钮

查看订单

结论

? 在这个故事中，我们了解了微服务架构的基础知识，并学习了如何通过简单的步骤使用 python? ? 构建微服务。

文章来源:https://blog.csdn.net/ddnosh/article/details/135302155
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