ServiceComb课题实验手册(二)

在本系列的上一篇文章中，我们搭建了 ServiceComb 的开发环境并开发了一个服务，在本文中，我们将继续搭建一个 Gateway 服务，以便于从为业务服务提供附加的能力。

构建Gateway服务项目

在 IDEA 中新建一个 maven 项目，将 GroupI 名为为: org.apache.servicecomb.samples， artifactId 指定为：bmi-gateway。项目建立后，打开项目中的 pom.xml 文件，将其修改为以下内容:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.apache.servicecomb.samples</groupId>
    <artifactId>bmi-gateway</artifactId>
    <version>1.3.0-SNAPSHOT</version>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <java-chassis.version>${project.version}</java-chassis.version>
        <spring-boot-1.version>1.5.14.RELEASE</spring-boot-1.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.apache.servicecomb</groupId>
                <artifactId>java-chassis-dependencies</artifactId>
                <version>${java-chassis.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot-1.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <!--add rest transport-->
        <dependency>
            <groupId>org.apache.servicecomb</groupId>
            <artifactId>transport-rest-vertx</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.servicecomb</groupId>
            <artifactId>spring-boot-starter-servicecomb</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.servicecomb</groupId>
            <artifactId>spring-boot-starter-discovery</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.servicecomb</groupId>
            <artifactId>spring-cloud-zuul</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.servicecomb</groupId>
            <artifactId>spring-cloud-zuul-zipkin</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.2.0.RELEASE</version>
                <configuration>
                    <fork>true</fork>
                    <mainClass>org.apache.servicecomb.samples.bmi.GatewayApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

保存以后， IDEA 会自动下载需要的第三方库。

构建项目启动类

因为需要用的能力都是在 ServiceComb 或 Spring Boot / Cloud 中实现了的，所以我们需要定义一个启动类即可。

新建一个 package, 名为: org.apache.servicecomb.samples.bmi, 然后在 package 中新建一个类，名为: GatewayApplication, 代码如下:

@SpringBootApplication
@EnableZuulProxy
@EnableServiceComb
public class GatewayApplication {
    public static void main(String[] args) {
        SpringApplication.run(GatewayApplication.class, args);
    }
}

定义服务配置文件

需要用到两个配置文件，都放在项目的 src/main/resources 目录下。

microservice.yaml

APPLICATION_ID: bmi
service_description:
  # name of the declaring microservice
  name: gateway
  version: 0.0.1
servicecomb:
  service:
    registry:
      address: http://127.0.0.1:30100

application.yaml

zuul:
  routes:
    calculator: /calculator/**

# disable netflix eurkea since it's not used for service discovery
ribbon:
  eureka:
    enabled: false

server:
  port: 8889

servicecomb:
  tracing:
    enabled: false

启动服务

在 IDEA 中运行刚才建的 bmi-gateway 项目。可以看到在 Run TAB 中的输出如下:

2019-10-25 11:11:17.321  INFO 7695 --- [           main] org.apache.servicecomb.core.SCBEngine    : Service information is shown below:
service center: [http://127.0.0.1:30100]
config center: not exist
AppID: bmi
ServiceName: gateway
Version: 0.0.1
Environment: production
ServiceID: 296cb6b50987ec12967e934d1e3df522901b1ccc
InstanceID; 1c2e1bf9f6d511e9ae530242ac110002

2019-10-25 11:11:17.323  INFO 7695 --- [           main] o.a.s.samples.bmi.GatewayApplication     : Started GatewayApplication in 16.035 seconds (JVM running for 17.602)
2019-10-25 11:11:17.392  INFO 7695 --- [worker-thread-3] o.a.s.s.c.h.ServiceRegistryClientImpl    : watching microservice 296cb6b50987ec12967e934d1e3df522901b1ccc successfully, the chosen service center address is 127.0.0.1:30100

可以看到，已经将自身注册到注册中心了。

验证

在浏览器地址栏中个输入:

1	http://localhost:8889/calculator/bmi?height=170&weight=50

浏览器中显示:

1	{"result":24.2,"instanceId":"c6753089f6cf11e9ae530242ac110002","callTime":"10:42:07"}

下一步

在下一篇文章中，将介绍 Gateway 的负载均衡能力。