http://bsideup.blogspot.com/2015/04/spring-boot-thrift-part3.html

Building Microservices with Spring Boot and Apache Thrift. Part 3. Asynchronous services

Posted on 4:12 PM  by Sergei Egorov

 

Have you thought about making your server asynchronous? How much time your server spent in database calls? External service calls? New shiny database library now supports asynchronous queries? It's time to processing requests in an async manner! And it's super easy with Facebook Swift!

Hardest part

How do you think, how much changes you need to do to make your Swift service asynchronous? Do you afraid of it? You already scheduled a week for this refactoring? Oh, that's nice:)

	import com.facebook.swift.service.ThriftMethod;
	import com.facebook.swift.service.ThriftService;
	+import com.google.common.util.concurrent.ListenableFuture;
	@ThriftService
	public interface TCalculatorService {
	@ThriftMethod
	- int calculate(int num1, int num2, TOperation op) throws TDivisionByZeroException;
	+ ListenableFuture<Integer> calculate(int num1, int num2, TOperation op) throws TDivisionByZeroException;
	}

view rawTCalculatorService.patch hosted with ❤ by GitHub

Now it's time to update your service implementation. Are you ready?

	import com.example.calculator.protocol.TOperation;
	+import com.google.common.util.concurrent.*;
	import org.springframework.stereotype.Component;
	import com.example.calculator.service.CalculatorService;
	import org.springframework.beans.factory.annotation.Autowired;
	+import java.util.concurrent.*;
	+
	@Component
	public class CalculatorServiceHandler implements TCalculatorService {
	@Autowired
	CalculatorService calculatorService;
	+ ScheduledExecutorService scheduledExecutorService = Executors.newScheduledThreadPool(10);
	+
	@Override
	- public int calculate(int num1, int num2, TOperation op) throws TDivisionByZeroException {
	+ public ListenableFuture<Integer> calculate(int num1, int num2, TOperation op) throws TDivisionByZeroException {
	+ return JdkFutureAdapters.listenInPoolThread(
	+ scheduledExecutorService.schedule(() -> {
	switch(op) {
	case ADD:
	return calculatorService.add(num1, num2);
	@@ -32,5 +40,7 @@
	default:
	throw new IllegalArgumentException("Unknown operation " + op);
	}
	+ }, 2, TimeUnit.SECONDS)
	+ );
	}
	}

view rawCalculatorServiceHandler.patch hosted with ❤ by GitHub

Hope you noticed this ScheduledExecutorService and 2 seconds delay. You shouldn't use it in your real application, this is just for example of promises (unless you want to simulate work for future optimizations like this guy: http://thedailywtf.com/articles/The-Speedup-Loop )

That's it, now your server is asynchronous. There is more - your clients can consume your service like before in non-async manner. How cool is that?

Full source code at GitHub: https://github.com/bsideup/spring-boot-swift/tree/async

Previous parts:

• Building Microservices with Spring Boot and Apache Thrift. Part 1
• Building Microservices with Spring Boot and Apache Thrift. Part 2. Swifty services