利用gRPC构建Python微服务(四)——在Kubernetes中部署

2022-01-19 约 1144 字预计阅读 3 分钟次阅读

上一篇中，主要向大家讲解了在Python中，基于gRPC protobufs实现客户端和服务端通讯，最后通过REST API对外界提供访问接口，在本篇文章中，向大家介绍如何利用在容器平台部署微服务模块。一些原有文章中对于容器的讲解被精简了。

全文导航

为了方便大家阅读，这里将全部目录进行一下索引，方便大家在老孙正经胡说(https://sunqi.site)中查看相关文章：

生产环境就绪的Python微服务

本节主要介绍使用容器来运行Python微服务环境，这里只保留Dockerfile部分内容。

Recommendations Dockerfile

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FROM python

RUN mkdir /service
COPY protobufs/ /service/protobufs/
COPY recommendations/ /service/recommendations/
WORKDIR /service/recommendations
RUN python -m pip install --upgrade pip
RUN python -m pip install -r requirements.txt
RUN python -m grpc_tools.protoc -I ../protobufs --python_out=. \
           --grpc_python_out=. ../protobufs/recommendations.proto

EXPOSE 50051
ENTRYPOINT [ "python", "recommendations.py" ]

构建

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$ docker build . -f recommendations/Dockerfile -t recommendations

运行

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$ docker run -p 127.0.0.1:50051:50051/tcp recommendations

Marketplace Dockerfile

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FROM python

RUN mkdir /service
COPY protobufs/ /service/protobufs/
COPY marketplace/ /service/marketplace/
WORKDIR /service/marketplace
RUN python -m pip install --upgrade pip
RUN python -m pip install -r requirements.txt
RUN python -m grpc_tools.protoc -I ../protobufs --python_out=. \
           --grpc_python_out=. ../protobufs/recommendations.proto

EXPOSE 5000
ENV FLASK_APP=marketplace.py
ENTRYPOINT [ "flask", "run", "--host=0.0.0.0"]

构建

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$ docker build . -f marketplace/Dockerfile -t marketplace

执行

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$ docker run -p 127.0.0.1:5000:5000/tcp marketplace

网络问题

在marketplace.py文件中

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recommendations_channel = grpc.insecure_channel("localhost:50051")

通过环境变量获取连接地址

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recommendations_host = os.getenv("RECOMMENDATIONS_HOST", "localhost")
recommendations_channel = grpc.insecure_channel(
    f"{recommendations_host}:50051"
)

重新构建，并启动

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$ docker build . -f marketplace/Dockerfile -t marketplace
$ docker run -p 127.0.0.1:5000:5000/tcp --network microservices \
             -e RECOMMENDATIONS_HOST=recommendations marketplace

Docker Compose

采用Docker compse文件降低编排复杂度

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version: "3.8"
services:

    marketplace:
        build:
            context: .
            dockerfile: marketplace/Dockerfile
        environment:
            RECOMMENDATIONS_HOST: recommendations
        image: marketplace
        networks:
            - microservices
        ports:
            - 5000:5000

    recommendations:
        build:
            context: .
            dockerfile: recommendations/Dockerfile
        image: recommendations
        networks:
            - microservices

networks:
    microservices:

现在的目录结构

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.
├── marketplace/
│   ├── marketplace.py
│   ├── requirements.txt
│   └── templates/
│       └── homepage.html
|
├── protobufs/
│   └── recommendations.proto
|
├── recommendations/
│   ├── recommendations.py
│   ├── recommendations_pb2.py
│   ├── recommendations_pb2_grpc.py
│   └── requirements.txt
│
└── docker-compose.yaml

启动

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$ docker-compose up

部署到Kubernetes

原文在这方面介绍的好细致，值得称赞，不过这里默认读者已经全部掌握了，不再赘述。

Marketplace

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---
apiVersion: apps/v1
kind: Deployment
metadata:
    name: marketplace
    labels:
        app: marketplace
spec:
    replicas: 3
    selector:
        matchLabels:
            app: marketplace
    template:
        metadata:
            labels:
                app: marketplace
        spec:
            containers:
                - name: marketplace
                  image: hidan/python-microservices-article-marketplace:0.1
                  env:
                      - name: RECOMMENDATIONS_HOST
                        value: recommendations

Recommendations

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---
apiVersion: apps/v1
kind: Deployment
metadata:
    name: recommendations
    labels:
        app: recommendations
spec:
    replicas: 3
    selector:
        matchLabels:
            app: recommendations
    template:
        metadata:
            labels:
                app: recommendations
        spec:
            containers:
                - name: recommendations
                  image: hidan/python-microservices-article-recommendations:0.1

Recommendation Service定义

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---
apiVersion: v1
kind: Service
metadata:
    name: recommendations
spec:
    selector:
        app: recommendations
    ports:
        - protocol: TCP
          port: 50051
          targetPort: 50051

Marketplace Service定义

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---
apiVersion: v1
kind: Service
metadata:
    name: marketplace
spec:
    type: LoadBalancer
    selector:
        app: marketplace
    ports:
        - protocol: TCP
          port: 5000
          targetPort: 5000

部署

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$ kubectl apply -f kubernetes.yaml