[#39] Initial approach to Hystrix concurrency strategy

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/hystrix/SleuthHystrixConcurrencyStrategy.java

@@ -0,0 +1,24 @@
+package org.springframework.cloud.sleuth.instrument.hystrix;
+
+import java.util.concurrent.Callable;
+
+import org.springframework.cloud.sleuth.TraceManager;
+import org.springframework.cloud.sleuth.instrument.TraceCallable;
+
+import com.netflix.hystrix.strategy.HystrixPlugins;
+import com.netflix.hystrix.strategy.concurrency.HystrixConcurrencyStrategy;
+
+public class SleuthHystrixConcurrencyStrategy extends HystrixConcurrencyStrategy {
+
+	private final TraceManager traceManager;
+
+	public SleuthHystrixConcurrencyStrategy(TraceManager traceManager) {
+		this.traceManager = traceManager;
+		HystrixPlugins.getInstance().registerConcurrencyStrategy(this);
+	}
+
+	@Override
+	public <T> Callable<T> wrapCallable(Callable<T> callable) {
+		return new TraceCallable<>(traceManager, callable);
+	}
+}

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/hystrix/SleuthHystrixConfiguration.java

@@ -0,0 +1,19 @@
+package org.springframework.cloud.sleuth.instrument.hystrix;
+
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.cloud.sleuth.TraceManager;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import com.netflix.hystrix.HystrixCommand;
+
+@Configuration
+@ConditionalOnClass(HystrixCommand.class)
+@ConditionalOnProperty(value = "spring.sleuth.hystrix.strategy.enabled", matchIfMissing = true)
+public class SleuthHystrixConfiguration {
+
+	@Bean SleuthHystrixConcurrencyStrategy sleuthHystrixConcurrencyStrategy(TraceManager traceManager) {
+		return new SleuthHystrixConcurrencyStrategy(traceManager);
+	}
+}

spring-cloud-sleuth-core/src/main/resources/META-INF/spring.factories

@@ -5,6 +5,7 @@ org.springframework.cloud.sleuth.log.SleuthLogAutoConfiguration,\
 org.springframework.cloud.sleuth.instrument.integration.TraceSpringIntegrationAutoConfiguration,\
 org.springframework.cloud.sleuth.instrument.async.AsyncCustomAutoConfiguration,\
 org.springframework.cloud.sleuth.instrument.async.AsyncDefaultAutoConfiguration,\
+org.springframework.cloud.sleuth.instrument.hystrix.SleuthHystrixConfiguration,\
 org.springframework.cloud.sleuth.instrument.scheduling.TraceSchedulingAutoConfiguration,\
 org.springframework.cloud.sleuth.instrument.web.TraceWebAutoConfiguration,\
 org.springframework.cloud.sleuth.instrument.web.client.TraceWebClientAutoConfiguration,\

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/hystrix/JavanicaITest.java

@@ -0,0 +1,125 @@
+package org.springframework.cloud.sleuth.instrument.hystrix;
+
+import static org.assertj.core.api.BDDAssertions.then;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.junit.After;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.SpringApplicationConfiguration;
+import org.springframework.cloud.netflix.hystrix.EnableHystrix;
+import org.springframework.cloud.sleuth.Span;
+import org.springframework.cloud.sleuth.TraceManager;
+import org.springframework.cloud.sleuth.instrument.DefaultTestAutoConfiguration;
+import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.EnableAspectJAutoProxy;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import com.jayway.awaitility.Awaitility;
+import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringApplicationConfiguration(classes = {
+		JavanicaITest.JavanicaITestConfiguration.class })
+public class JavanicaITest {
+
+	@Autowired JavanicaClass javanicaClass;
+	@Autowired JavanicaDelegation javanicaDelegation;
+	@Autowired TraceManager traceManager;
+
+	@Test
+	public void should_set_span_on_an_hystrix_command_annotated_method() {
+		final Span span = givenASpanInCurrentThread();
+
+		whenHystrixCommandGetsExecutedViaJavanica();
+
+		thenSpanPutInTheAsyncThreadIsSameAs(span);
+	}
+
+	private Span givenASpanInCurrentThread() {
+		Span span = this.traceManager.startSpan("existing").getSpan();
+		this.traceManager.continueSpan(span);
+		return span;
+	}
+
+	private void whenHystrixCommandGetsExecutedViaJavanica() {
+		this.javanicaDelegation.doSthThatDelegatesToJavanica();
+	}
+
+	private void thenSpanPutInTheAsyncThreadIsSameAs(final Span span) {
+		Awaitility.await().until(new Runnable() {
+			@Override
+			public void run() {
+				then(span.getTraceId()).isNotNull()
+						.isEqualTo(javanicaClass.getTraceId());
+				then(span.getName())
+						.isNotEqualTo(javanicaClass.getSpanName());
+			}
+		});
+	}
+
+	@After
+	public void cleanTrace() {
+		TraceContextHolder.removeCurrentTrace();
+	}
+
+	@DefaultTestAutoConfiguration
+	@EnableHystrix
+	@EnableAspectJAutoProxy(proxyTargetClass = true)
+	@Configuration
+	public static class JavanicaITestConfiguration {
+
+		@Bean
+		JavanicaClass javanicaClass() {
+			return new JavanicaClass();
+		}
+
+		@Bean
+		JavanicaDelegation javanicaDelegation() {
+			return new JavanicaDelegation(javanicaClass());
+		}
+	}
+
+	public static class JavanicaDelegation {
+
+		private final JavanicaClass javanicaClass;
+
+		public JavanicaDelegation(JavanicaClass javanicaClass) {
+			this.javanicaClass = javanicaClass;
+		}
+
+		public void doSthThatDelegatesToJavanica() {
+			this.javanicaClass.doSth();
+		}
+	}
+
+	public static class JavanicaClass {
+
+		AtomicReference<Span> span;
+
+		@HystrixCommand
+		public void doSth() {
+			this.span = new AtomicReference<>(TraceContextHolder.getCurrentSpan());
+		}
+
+		public String getTraceId() {
+			if (this.span == null || this.span.get() == null || (this.span.get() != null
+					&& this.span.get().getTraceId() == null)) {
+				return null;
+			}
+			return this.span.get().getTraceId();
+		}
+
+		public String getSpanName() {
+			if (this.span == null
+					|| (this.span.get() != null && this.span.get().getName() == null)) {
+				return null;
+			}
+			return this.span.get().getName();
+		}
+	}
+}

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/TraceAsyncITest.java

@@ -25,15 +25,12 @@ import com.jayway.awaitility.Awaitility;
 
 @RunWith(SpringJUnit4ClassRunner.class)
 @SpringApplicationConfiguration(classes = {
-		TraceAsyncITest.CorrelationIdAsyncSpecConfiguration.class })
+		TraceAsyncITest.TraceAsyncITestConfiguration.class })
 public class TraceAsyncITest {
 
-	@Autowired
-	AsyncClass asyncClass;
-	@Autowired
-	AsyncDelegation asyncDelegation;
-	@Autowired
-	TraceManager traceManager;
+	@Autowired AsyncClass asyncClass;
+	@Autowired AsyncDelegation asyncDelegation;
+	@Autowired TraceManager traceManager;
 
 	@Test
 	public void should_set_span_on_an_async_annotated_method() {
@@ -75,7 +72,7 @@ public class TraceAsyncITest {
 	@EnableAsync
 	@EnableAspectJAutoProxy(proxyTargetClass = true)
 	@Configuration
-	public static class CorrelationIdAsyncSpecConfiguration {
+	public static class TraceAsyncITestConfiguration {
 
 		@Bean
 		AsyncClass asyncClass() {