http://bsideup.blogspot.com/2015/04/spring-boot-thrift-part2.html
In previous article I showed you how to use pure Apache Thrift to create protocols for your services. This time I will explain how to use Facebook Swift (not the best name for project BTW :)) to get rid of Thrift IDL files for server code.
Few words about Swift. Swift - Java annotation-based generator for Apache Thrift. It‘s priceless when you develop your APIs in Java and want to expose them to the other world using Apache Thrift.
Protocol
Lets recreate our previous example ( https://github.com/bsideup/spring-boot-thrift ) with it. Start with simple build.gradle file:
| apply plugin: ‘java‘ | |
| apply plugin: ‘spring-boot‘ | |
| buildscript { | |
| repositories { | |
| jcenter() | |
| } | |
| dependencies { | |
| classpath("org.springframework.boot:spring-boot-gradle-plugin:1.2.1.RELEASE") | |
| } | |
| } | |
| repositories { | |
| jcenter() | |
| } | |
| sourceCompatibility = 1.8 | |
| targetCompatibility = 1.8 | |
| dependencies { | |
| compile "org.projectlombok:lombok:1.16.2" | |
| compile("org.springframework.boot:spring-boot-starter-web") | |
| compile ‘com.facebook.swift:swift-annotations:0.14.1‘ | |
| compile ‘com.facebook.swift:swift-service:0.14.1‘ | |
| compile ‘com.facebook.swift:swift-codec:0.14.1‘ | |
| compile ‘com.facebook.nifty:nifty-core:0.14.1‘ | |
| compile ‘org.apache.thrift:libthrift:0.9.1‘ | |
| testCompile "org.springframework.boot:spring-boot-starter-test" | |
| } |
view rawbuild.gradle hosted with ? by GitHub
Nothing special, Spring Boot with few Facebook Swift libraries.
Next we need to add Swift protocol classes:
| package com.example.calculator.protocol; | |
| 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; | |
| } |
view rawTCalculatorService.java hosted with ? by GitHub
Exception is simple Swift struct which extend Exception (See Ma no TException)
| package com.example.calculator.protocol; | |
| import com.facebook.swift.codec.ThriftStruct; | |
| @ThriftStruct | |
| public final class TDivisionByZeroException extends Exception { | |
| } |
view rawTDivisionByZeroException.java hosted with ? by GitHub
Enums are handled with Swift, so we don‘t need to annotate them (but we can)
| package com.example.calculator.protocol; | |
| public enum TOperation { | |
| ADD, | |
| SUBTRACT, | |
| MULTIPLY, | |
| DIVIDE | |
| } |
view rawTOperation.java hosted with ? by GitHub
Next - application main class for Spring Boot:
| package com.example.calculator; | |
| import com.example.calculator.protocol.TCalculatorService; | |
| import com.facebook.nifty.processor.NiftyProcessorAdapters; | |
| import com.facebook.swift.codec.ThriftCodecManager; | |
| import com.facebook.swift.service.ThriftEventHandler; | |
| import com.facebook.swift.service.ThriftServiceProcessor; | |
| import org.apache.thrift.protocol.*; | |
| import org.apache.thrift.server.TServlet; | |
| import org.springframework.boot.SpringApplication; | |
| import org.springframework.boot.autoconfigure.EnableAutoConfiguration; | |
| import org.springframework.context.annotation.*; | |
| import javax.servlet.Servlet; | |
| import java.util.Arrays; | |
| @Configuration | |
| @EnableAutoConfiguration | |
| @ComponentScan | |
| public class CalculatorApplication { | |
| public static void main(String[] args) { | |
| SpringApplication.run(CalculatorApplication.class, args); | |
| } | |
| @Bean | |
| TProtocolFactory tProtocolFactory() { | |
| return new TBinaryProtocol.Factory(); | |
| } | |
| @Bean | |
| ThriftCodecManager thriftCodecManager() { | |
| return new ThriftCodecManager(); | |
| } | |
| @Bean | |
| Servlet thrift(ThriftCodecManager thriftCodecManager, TProtocolFactory protocolFactory, TCalculatorService exampleService) { | |
| ThriftServiceProcessor processor = new ThriftServiceProcessor(thriftCodecManager, Arrays.<ThriftEventHandler>asList(), exampleService); | |
| return new TServlet( | |
| NiftyProcessorAdapters.processorToTProcessor(processor), | |
| protocolFactory, | |
| protocolFactory | |
| ); | |
| } | |
| } |
view rawCalculatorApplication.java hosted with ? by GitHub
Test
Now we‘re ready to write some tests:
| package com.example.calculator; | |
| import com.example.calculator.protocol.TCalculatorService; | |
| import com.example.calculator.protocol.TDivisionByZeroException; | |
| import com.example.calculator.protocol.TOperation; | |
| import com.facebook.nifty.client.HttpClientConnector; | |
| import com.facebook.swift.codec.ThriftCodecManager; | |
| import com.facebook.swift.service.ThriftClientManager; | |
| import org.apache.thrift.protocol.TProtocolFactory; | |
| import org.junit.Before; | |
| import org.junit.Test; | |
| import org.junit.runner.RunWith; | |
| import org.springframework.beans.factory.annotation.Autowired; | |
| import org.springframework.beans.factory.annotation.Value; | |
| import org.springframework.boot.test.IntegrationTest; | |
| import org.springframework.boot.test.SpringApplicationConfiguration; | |
| import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; | |
| import org.springframework.test.context.web.WebAppConfiguration; | |
| import java.net.URI; | |
| import static org.junit.Assert.*; | |
| @RunWith(SpringJUnit4ClassRunner.class) | |
| @SpringApplicationConfiguration(classes = CalculatorApplication.class) | |
| @WebAppConfiguration | |
| @IntegrationTest("server.port:0") | |
| public class CalculatorApplicationTest { | |
| @Autowired | |
| TProtocolFactory protocolFactory; | |
| @Autowired | |
| ThriftCodecManager thriftCodecManager; | |
| @Value("${local.server.port}") | |
| protected int port; | |
| protected TCalculatorService client; | |
| @Before | |
| public void setUp() throws Exception { | |
| HttpClientConnector connector = new HttpClientConnector(URI.create("http://localhost:" + port + "/thrift/")); | |
| ThriftClientManager clientManager = new ThriftClientManager(thriftCodecManager); | |
| client = clientManager.createClient(connector, TCalculatorService.class).get(); | |
| } | |
| @Test | |
| public void testAdd() throws Exception { | |
| assertEquals(5, client.calculate(2, 3, TOperation.ADD)); | |
| } | |
| @Test | |
| public void testSubtract() throws Exception { | |
| assertEquals(3, client.calculate(5, 2, TOperation.SUBTRACT)); | |
| } | |
| @Test | |
| public void testMultiply() throws Exception { | |
| assertEquals(10, client.calculate(5, 2, TOperation.MULTIPLY)); | |
| } | |
| @Test | |
| public void testDivide() throws Exception { | |
| assertEquals(2, client.calculate(10, 5, TOperation.DIVIDE)); | |
| } | |
| @Test(expected = TDivisionByZeroException.class) | |
| public void testDivisionByZero() throws Exception { | |
| client.calculate(10, 0, TOperation.DIVIDE); | |
| } | |
| } |
view rawCalculatorApplicationTest.java hosted with ? by GitHub
As you can see, only difference here (compared to Thrift version) is setUp method.
Diff with Thrift version
Implementation
We still have no Swift service implementation. Implementation of handler looks almost the same asprevious:
| package com.example.calculator.handler; | |
| import com.example.calculator.protocol.TCalculatorService; | |
| import com.example.calculator.protocol.TDivisionByZeroException; | |
| import com.example.calculator.protocol.TOperation; | |
| import org.springframework.stereotype.Component; | |
| import com.example.calculator.service.CalculatorService; | |
| import org.springframework.beans.factory.annotation.Autowired; | |
| @Component | |
| public class CalculatorServiceHandler implements TCalculatorService { | |
| @Autowired | |
| CalculatorService calculatorService; | |
| @Override | |
| public int calculate(int num1, int num2, TOperation op) throws TDivisionByZeroException { | |
| switch(op) { | |
| case ADD: | |
| return calculatorService.add(num1, num2); | |
| case SUBTRACT: | |
| return calculatorService.subtract(num1, num2); | |
| case MULTIPLY: | |
| return calculatorService.multiply(num1, num2); | |
| case DIVIDE: | |
| try { | |
| return calculatorService.divide(num1, num2); | |
| } catch(IllegalArgumentException e) { | |
| throw new TDivisionByZeroException(); | |
| } | |
| default: | |
| throw new IllegalArgumentException("Unknown operation " + op); | |
| } | |
| } | |
| } |
view rawCalculatorServiceHandler.java hosted with ? by GitHub
Now if you will run tests you should see all tests green.
Thrift integration
But hey, how about other non-Java consumers of service? Don‘t worry, Swift comes with a tool for generating *.thrift files from annotated Java classes:https://github.com/facebook/swift/tree/master/swift2thrift-generator-cli
Example output for our service will be:
| namespace java.swift com.example.calculator.protocol | |
| namespace java com.example.calculator.protocol | |
| namespace py com.example.calculator.protocol | |
| namespace as3 com.example.calculator.protocol | |
| enum TOperation { | |
| ADD, SUBTRACT, MULTIPLY, DIVIDE | |
| } | |
| exception TDivisionByZeroException { | |
| } | |
| service TCalculatorService { | |
| i32 calculate(1: i32 arg0, 2: i32 arg1, 3: TOperation arg2) throws (1: TDivisionByZeroException ex1); | |
| } |
view rawcalculator.thrift hosted with ? by GitHub
Conclusion
Full source files for this example can be found at GitHub: https://github.com/bsideup/spring-boot-swift
Next time I will show you how to write Async Thrift services using Swift with minimal changes. Stay tuned!