ServiceComb support users to define a customized handler and and invoke the handler in handler chain.

• Customize a handler by implement Handler interface, for example:

  public class MyHandler implements Handler {
    private static final Logger LOGGER = LoggerFactory.getLogger(MyHandler.class);
    @Override
    public void handle(Invocation invocation, AsyncResponse asyncResponse) throws Exception {
      //code before
      LOGGER.info("It's my handler! \r\n");
      invocation.next(response -> {
        // code after
        asyncResponse.handle(response);
      });
    }
  }

• Define handler id and class in cse.handler.xml config item under resources/config directory

  <config>
      <handler id="myhandler" 		     class="org.apache.servicecomb.samples.customerhandler.handlers.MyHandler" />
  </config>
  

• Configure customized MyHandler in microservice.yaml file along with other handler together

  cse:
    # other configurations omitted
    handler:
      chain:
        Consumer:
          default: bizkeeper-consumer,loadbalance, myhandler

1. Start the ServiceComb/Service Center

   • how to start the service center
   • make sure service center address is configured correctly in microservice.yaml file

   cse:
     service:
       registry:
         address: http://127.0.0.1:30100		#service center address

2. Start the custom-handler-provider service

   • Start provider service by maven

     Compile the source code at root directory of ServiceComb Java Chassis, which is servicecomb-java-chassis/, and use mvn exec to execute the main class CustomHandlerProviderMain.

     cd servicecomb-java-chassis/			#need to complie code at root directory
     mvn clean install -Psamples -DskipTests			#only need to install at first time.
     cd samples/custom-handler-sample/custom-handler-provider/
     mvn exec:java -Dexec.mainClass="org.apache.servicecomb.samples.customerhandler.provider.CustomHandlerProviderMain"

   • Start provider service by IDE

     Import the project by InteliJ IDEA or Eclipse, add sample module to pom.xml file in root module servicecomb-java-chassis/pom.xml, and add <module>samples</module> to <modules></modules> block, Then find main function CustomHandlerProviderMain of provider service and RUN it like any other Java program.

3. Start the custom-handler-consumer service

   Just like how to start custom-handler-provider service. But the main class of custom-handler-consumer service is CustomHandlerCustomerMain.

   cd samples/custom-handler-sample/custom-handler-consumer
   mvn exec:java -Dexec.mainClass="org.apache.servicecomb.samples.customerhandler.consumer.CustomHandlerCustomerMain"

4. How to verify On the producer side, the output should contain the following stuffs if the producer starts up successfully:

   1. 'swagger: 2.0 info: version: 1.0.0 ...' means the producer generated swagger contracts
   2. 'rest listen success. address=0.0.0.0:8080' means the rest endpoint is listening on port 8080
   3. 'highway listen success. address=0.0.0.0:7070' means the highway endpoint is listening on port 7070
   4. 'Register microservice instance success' means the producer has registered successfully to service center

   On the consumer side, you can see the following outputs:

   1. 'It's my handler!' means custom handler had take effect