Fixed Travis script for branches

Added test to ensure that traces are cleared, added fix for Hystrix commands

.travis.yml

@@ -8,7 +8,7 @@ before_install:
   - gem install asciidoctor
 install:
 - ./mvnw install -P docs -q -U -DskipTests=true -Dmaven.test.redirectTestOutputToFile=true
-- ./docs/src/main/asciidoc/ghpages.sh
+- '[ "${TRAVIS_BRANCH}" != "master" ] || ./docs/src/main/asciidoc/ghpages.sh'
 script:
 - '[ "${TRAVIS_PULL_REQUEST}" != "false" ] || ./mvnw -s .settings.xml deploy -nsu -Dmaven.test.redirectTestOutputToFile=true'
 - '[ "${TRAVIS_PULL_REQUEST}" = "false" ] || ./mvnw install -nsu -Dmaven.test.redirectTestOutputToFile=true'

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

@@ -16,6 +16,7 @@
 
 package org.springframework.cloud.sleuth.instrument.hystrix;
 
+import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.Trace;
 import org.springframework.cloud.sleuth.TraceManager;
 
@@ -35,36 +36,42 @@ import com.netflix.hystrix.HystrixThreadPoolKey;
  */
 public abstract class TraceCommand<R> extends HystrixCommand<R> {
 
-	private TraceManager traceManager;
+	private final TraceManager traceManager;
+	private final Span parentSpan;
 
 	protected TraceCommand(TraceManager traceManager, HystrixCommandGroupKey group) {
 		super(group);
 		this.traceManager = traceManager;
+		this.parentSpan = traceManager.getCurrentSpan();
 	}
 
 	protected TraceCommand(TraceManager traceManager, HystrixCommandGroupKey group, HystrixThreadPoolKey threadPool) {
 		super(group, threadPool);
 		this.traceManager = traceManager;
+		this.parentSpan = traceManager.getCurrentSpan();
 	}
 
 	protected TraceCommand(TraceManager traceManager, HystrixCommandGroupKey group, int executionIsolationThreadTimeoutInMilliseconds) {
 		super(group, executionIsolationThreadTimeoutInMilliseconds);
 		this.traceManager = traceManager;
+		this.parentSpan = traceManager.getCurrentSpan();
 	}
 
 	protected TraceCommand(TraceManager traceManager, HystrixCommandGroupKey group, HystrixThreadPoolKey threadPool, int executionIsolationThreadTimeoutInMilliseconds) {
 		super(group, threadPool, executionIsolationThreadTimeoutInMilliseconds);
 		this.traceManager = traceManager;
+		this.parentSpan = traceManager.getCurrentSpan();
 	}
 
 	protected TraceCommand(TraceManager traceManager, Setter setter) {
 		super(setter);
 		this.traceManager = traceManager;
+		this.parentSpan = traceManager.getCurrentSpan();
 	}
 
 	@Override
 	protected R run() throws Exception {
-		Trace trace = this.traceManager.startSpan(getCommandKey().name());
+		Trace trace = this.traceManager.startSpan(getCommandKey().name(), parentSpan);
 		try {
 			return doRun();
 		} finally {

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

@@ -0,0 +1,79 @@
+package org.springframework.cloud.sleuth.instrument.hystrix;
+
+import static com.netflix.hystrix.HystrixCommand.Setter.withGroupKey;
+import static com.netflix.hystrix.HystrixCommandGroupKey.Factory.asKey;
+import static org.assertj.core.api.BDDAssertions.then;
+
+import org.junit.After;
+import org.junit.Test;
+import org.mockito.Mockito;
+import org.springframework.cloud.sleuth.MilliSpan;
+import org.springframework.cloud.sleuth.Trace;
+import org.springframework.cloud.sleuth.TraceManager;
+import org.springframework.cloud.sleuth.sampler.AlwaysSampler;
+import org.springframework.cloud.sleuth.trace.DefaultTraceManager;
+import org.springframework.cloud.sleuth.trace.TraceContextHolder;
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.util.JdkIdGenerator;
+
+import com.netflix.hystrix.HystrixCommandKey;
+import com.netflix.hystrix.HystrixThreadPoolProperties;
+
+public class TraceCommandTest {
+
+	static final String EXPECTED_TRACE_ID = "A";
+	TraceManager traceManager = new DefaultTraceManager(new AlwaysSampler(),
+			new JdkIdGenerator(), Mockito.mock(ApplicationEventPublisher.class));
+
+	@Test
+	public void should_remove_span_from_thread_local_after_finishing_work()
+			throws Exception {
+		Trace firstTraceFromHystrix = givenACommandWasExecuted(traceReturningCommand());
+
+		Trace secondTraceFromHystrix = whenCommandIsExecuted(traceReturningCommand());
+
+		then(secondTraceFromHystrix.getSpan().getTraceId()).as("second trace id")
+				.isNotEqualTo(firstTraceFromHystrix.getSpan().getTraceId()).as("first trace id");
+		then(secondTraceFromHystrix.getSavedTrace()).as("saved trace as remnant of first trace")
+				.isNull();
+	}
+
+	@Test
+	public void should_run_Hystrix_command_with_span_passed_from_parent_thread() {
+		givenATraceIsPresentInTheCurrentThread();
+		TraceCommand<Trace> command = traceReturningCommand();
+
+		Trace traceFromCommand = whenCommandIsExecuted(command);
+
+		then(traceFromCommand).as("Trace from the Hystrix Thread").isNotNull();
+		then(traceFromCommand.getSpan().getTraceId()).isEqualTo(EXPECTED_TRACE_ID);
+	}
+
+	@After
+	public void cleanUpTrace() {
+		TraceContextHolder.removeCurrentTrace();
+	}
+
+	private Trace givenATraceIsPresentInTheCurrentThread() {
+		return traceManager.startSpan("test", MilliSpan.builder().traceId(EXPECTED_TRACE_ID).build());
+	}
+
+	private TraceCommand<Trace> traceReturningCommand() {
+		return new TraceCommand<Trace>(traceManager,  withGroupKey(asKey(""))
+				.andCommandKey(HystrixCommandKey.Factory.asKey("")).andThreadPoolPropertiesDefaults(
+						HystrixThreadPoolProperties.Setter().withMaxQueueSize(1).withCoreSize(1))) {
+			@Override
+			public Trace doRun() throws Exception {
+				return TraceContextHolder.getCurrentTrace();
+			}
+		};
+	}
+
+	private Trace whenCommandIsExecuted(TraceCommand<Trace> command) {
+		return command.execute();
+	}
+
+	private Trace givenACommandWasExecuted(TraceCommand<Trace> command) {
+		return whenCommandIsExecuted(command);
+	}
+}