Develop Microservice with Transparent RPC
Concept Description
The transparent remote procedure call(RPC) development mode is a development mode based on API and API implementation. The service developer does not need to use the description of Spring MVC and JAX-RS.
Development Example
Step 1 Import dependencies into your maven project:
<dependencyManagement> <dependencies> <dependency> <groupId>org.apache.servicecomb</groupId> <artifactId>java-chassis-dependencies</artifactId> <version>1.0.0-m1</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <dependencies> <!--transport can optional import through endpoint setting in microservice.yaml, we import both rest and highway as example--> <dependency> <groupId>org.apache.servicecomb</groupId> <artifactId>transport-rest-vertx</artifactId> </dependency> <dependency> <groupId>org.apache.servicecomb</groupId> <artifactId>transport-highway</artifactId> </dependency> <dependency> <groupId>org.apache.servicecomb</groupId> <artifactId>provider-pojo</artifactId> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> </dependency> </dependencies>
Step 2 Define a service API. Compile the Java API definition based on the API definition defined before development. The code is as follows:
public interface Hello { String sayHi(String name); String sayHello(Person person); }
Step 3 implement the service. The implementation of the Hello service is as follows:
import org.apache.servicecomb.samples.common.schema.Hello; import org.apache.servicecomb.samples.common.schema.models.Person; public class HelloImpl implements Hello { @Override public String sayHi(String name) { return "Hello " + name; } @Override public String sayHello(Person person) { return "Hello person " + person.getName(); } }
Step 4 Release the service. The transparent RPC development mode supports two service release mode: Spring XML configuration and Annotation configuration:
Spring XML configuration Mode: Create the pojoHello.bean.xml file in the resources/META-INF/spring directory and declare the schema in the file. The content of the file is as follows:
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:util="http://www.springframework.org/schema/util" xmlns:cse="http://www.huawei.com/schema/paas/cse/rpc" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans classpath:org/springframework/beans/factory/xml/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.huawei.com/schema/paas/cse/rpc classpath:META-INF/spring/spring-paas-cse-rpc.xsd"> <cse:rpc-schema schema-id="pojoHello" implementation="org.apache.servicecomb.samples.pojo.provider.PojoHelloImpl"/> </beans>
Annotation configuration Mode: @RpcSchema is used to define schema during the API Hello implementation. The code is as follows:
import org.apache.servicecomb.provider.pojo.RpcSchema; @RpcSchema(schemaId = "pojoHello") public class HelloImpl implements Hello { @Override public String sayHi(String name) { return "Hello " + name; } @Override public String sayHello(Person person) { return "Hello person " + person.getName(); } }
In the pojoHello.bean.xml file of resources/META-INF/spring directory, configure base-package that performs scanning. The content of the file is as follows:
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:util="http://www.springframework.org/schema/util" xmlns:cse="http://www.huawei.com/schema/paas/cse/rpc" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans classpath:org/springframework/beans/factory/xml/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.huawei.com/schema/paas/cse/rpc classpath:META-INF/spring/spring-paas-cse-rpc.xsd"> <context:component-scan base-package="org.apache.servicecomb.samples.pojo.provider"/> </beans>
Note: THE PATH FOR RPC IS ClassName/MethodName
, AND THE METHOD IS POST
.
In this sample the Path of sayHi is /HelloImpl/sayHi
, and the Path of sayHello is /HelloImpl/sayHello
.
NOTE: Different from the Spring MVC and JAX-RS development modes, the transparent RPC development mode used
@RpcSchema
instead of@RestSchema
.
Step 5 Add service definition file:
Add microservice.yaml file into resources folder of your project.
Step 6 Add Main class:
import org.apache.servicecomb.foundation.common.utils.BeanUtils; import org.apache.servicecomb.foundation.common.utils.Log4jUtils; public class Application { public static void main(String[] args) throws Exception { //initializing log, loading bean(including its parameters), and registering service, more detail can be found here : http://servicecomb.incubator.apache.org/users/application-boot-process/ Log4jUtils.init(); BeanUtils.init(); } }