SpringCloud 融入 Python - Flask

時間 2019-12-26

標籤 springcloud 融入 python flask 欄目 Python 简体版

原文原文鏈接

前言

該篇文章分享如何將Python Web服務融入到Spring Cloud微服務體系中，並調用其服務，Python Web框架用的是Flaskjava

方案

Sidecar+ Flask，在這裏，咱們會使用Sidecar將Python接口註冊到SpringCloud中，將Python接口看成Java接口進行調用（經過SpringCloud去調用Sidecar，而後經過Sidecar去轉發咱們的程序請求）python

Sidecar是SpringCloud提供的一個可將第三方的rest接口集成到SpringCloud中的工具

Python服務

manage.py

import json
from flask import Flask, Response, request, make_response, jsonify

app = Flask(__name__)

@app.route("/health")
def health():
    result = {'status': 'UP'}
    return Response(json.dumps(result), mimetype='application/json')

@app.route("/getUser")
def getUser():
    result = {'username': 'python', 'password': 'python'}
    return Response(json.dumps(result), mimetype='application/json')

@app.errorhandler(404)
def not_found(error):
    return make_response(jsonify({'error': 'Not found'}), 404)

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=3000)

大體說下上述代碼，Python服務監聽3000端口，health方法用於給Sidecar提供健康接口，用於實時向Sidecar提供本身的健康狀態，getUser是Python向外界提供的服務web

運行方式

python manage.py runserver

sidecar工程

添加依賴

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-netflix-sidecar</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>

SidecarApplication.java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.sidecar.EnableSidecar;

@EnableSidecar
@SpringBootApplication
public class SidecarApplication {

    public static void main(String[] args) {
        SpringApplication.run(SidecarApplication.class, args);
    }
}

application.yml

spring:
  profiles:
    active: "dev"
  application:
    name: demo-sidecar
    
sidecar:
   port: 3000
   health-uri: http://localhost:${sidecar.port}/health
   
ribbon:
   ConnectTimeout: 50000
   ReadTimeout: 50000
   
hystrix:
   command:
      default:
         execution:
            isolation:
               thread:
                  timeoutInMilliseconds: 10000
    
server:
  port: 8326

eureka:
  client:
    healthcheck:
      enabled: true
    service-url:
      defaultZone: http://${registry.host:localhost}:${registry.port:8761}/eureka/

registry:
  host: localhost
  port: 31091

大體說下上述代碼，main方法要使用@EnableSidecar註解，sidecar port表明監聽Python運行的端口，server port表明Sidecar運行的端口，spring application name表明Sidecar的服務名，sidecar health-uri是Python健康接口，指向python的健康服務

spring

服務調用 - DemoServer工程(端口8325)

調用方式一 : RestTemplate

DemoServerApplication.java

@SpringBootApplication
public class DemoServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoServerApplication.class, args);
    }
    
    @Bean
    @LoadBalanced
    RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

RestTemplateController.java

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class RestTemplateController {
    @Autowired
    private RestTemplate restTemplate;
    @RequestMapping("/java-user")
    public String JavaUser() {
        return "{'username': 'java', 'password': 'java'}"  ;
    }

    @RequestMapping("/python-user")
    public String PythonUser() {
        return restTemplate.getForEntity("http://demo-sidecar/getUser", String.class).getBody();
//      return restTemplate.getForEntity("http://localhost:3000/getUser", String.class).getBody();
    }
}

這裏作下說明，@LoadBalanced用於開啓負載均衡，在這裏有兩種調用方式，使用和不使用@LoadBalanced
使用@LoadBalanced註解後，RestTemplate能夠直接調用服務名

@Bean
@LoadBalanced
RestTemplate restTemplate() {
    return new RestTemplate();
}
++++++++++++++++++++++++++++++
return restTemplate.getForEntity("http://demo-sidecar/getUser", String.class).getBody();

不使用@LoadBalanced註解，RestTemplate調用的就是固定的IP+PORT

@Bean
// @LoadBalanced
RestTemplate restTemplate() {
    return new RestTemplate();
}
++++++++++++++++++++++++++++++
return restTemplate.getForEntity("http://localhost:3000/getUser", String.class).getBody();

服務的啓動順序：Python服務，註冊中心，sidecar工程，DemoServer工程
運行結果

調用方式二: Feign

congfig類中需添加註解@EnableFeignClients，具體使用請百度
SidecarController.java

@RestController
public class SidecarController {
    private SidecarAPIClient sidecarAPIClient;
    
    @Autowired
    public SidecarController(SidecarAPIClient sidecarAPIClient) {
        this.sidecarAPIClient = sidecarAPIClient;
    }
    
    @GetMapping("/getUser")
    public Object getUser() {
        return this.sidecarAPIClient.getUser();
    }
}

SidecarAPIClient.java

@FeignClient(name="demo-sidecar", configuration = FeignConfigure.class)
public interface SidecarAPIClient {

    @GetMapping("/getUser")
    Object getUser();
}

FeignConfigure.java

import feign.Logger;
import feign.codec.Encoder;
import feign.form.spring.SpringFormEncoder;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.web.HttpMessageConverters;
import org.springframework.cloud.netflix.feign.support.SpringEncoder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class FeignConfigure {
    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.FULL;
    }

    @Autowired
    private ObjectFactory<HttpMessageConverters> messageConverters;
   
    @Bean
    public Encoder feignFormEncoder() {
        return new SpringFormEncoder(new SpringEncoder(messageConverters));
    }
}

服務的啓動順序：Python服務，註冊中心，sidecar工程，DemoServer工程
調用結果

至此，已完成微服務調用Python Web服務

Sidecar總結

Sidecar是一個用於監聽非JVM應用程序(能夠是Python或者Node或者Php等等)的一個工具，經過Sidecar能夠實現Java和第三方應用程序的雙向交互
第三方應用程序必需要實現一個接口，實時向Sidecar報告本身的狀態，告訴Sidecar本身還在運行着。
Sidecar應用程序必須和第三方應用程序運行在同一臺電腦上，也就是說他們之間是localhost，不能是IP訪問