Adding the spring.instance_id tag

without this tag it's impossible to discern from which server was the given span originated
    with this change we're adding a tag in which we're passing the instance id value. The value can be taken either from Cloud Foundry or from a concatanation of some local properties like instance_id / application name / application port etc.

    fixes #369

spring-cloud-sleuth-core/pom.xml

@@ -36,6 +36,10 @@
 			<artifactId>spring-boot-starter-actuator</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.cloud</groupId>
+			<artifactId>spring-cloud-commons</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.cloud</groupId>
 			<artifactId>spring-cloud-starter-feign</artifactId>

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/Span.java

@@ -134,6 +134,11 @@ public class Span {
 	 */
 	public static final String SPAN_PEER_SERVICE_TAG_NAME = "peer.service";
 
+	/**
+	 * ID of the instance from which the span was originated.
+	 */
+	public static final String INSTANCEID = "spring.instance_id";
+
 	private final long begin;
 	private long end = 0;
 	private final String name;

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/trace/DefaultTracerTests.java

@@ -183,6 +183,7 @@ public class DefaultTracerTests {
 		then(span).hasATag("key", "value").hasLoggedAnEvent("event");
 		then(continuedSpan).hasATag("key", "value").hasLoggedAnEvent("event");
 		then(span).isEqualTo(continuedSpan);
+		tracer.close(span);
 	}
 
 	private Span assertSpan(List<Span> spans, Long parentId, String name) {

spring-cloud-sleuth-stream/src/main/java/org/springframework/cloud/sleuth/stream/SleuthStreamAutoConfiguration.java

@@ -37,6 +37,7 @@ import org.springframework.cloud.stream.config.ChannelBindingAutoConfiguration;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.Ordered;
+import org.springframework.core.env.Environment;
 import org.springframework.integration.config.GlobalChannelInterceptor;
 import org.springframework.integration.scheduling.PollerMetadata;
 import org.springframework.messaging.support.ChannelInterceptor;
@@ -76,8 +77,8 @@ public class SleuthStreamAutoConfiguration {
 	@Bean
 	@ConditionalOnMissingBean
 	public StreamSpanReporter sleuthStreamSpanReporter(HostLocator endpointLocator,
-			SpanMetricReporter spanMetricReporter) {
-		return new StreamSpanReporter(endpointLocator, spanMetricReporter);
+			SpanMetricReporter spanMetricReporter, Environment environment) {
+		return new StreamSpanReporter(endpointLocator, spanMetricReporter, environment);
 	}
 
 	@Bean(name = StreamSpanReporter.POLLER)

spring-cloud-sleuth-stream/src/main/java/org/springframework/cloud/sleuth/stream/StreamSpanReporter.java

@@ -17,17 +17,20 @@
 package org.springframework.cloud.sleuth.stream;
 
 import java.lang.invoke.MethodHandles;
+import java.util.Arrays;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.LinkedBlockingQueue;
 
-import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.springframework.cloud.commons.util.IdUtils;
+import org.springframework.cloud.sleuth.Log;
 import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.SpanReporter;
 import org.springframework.cloud.sleuth.metric.SpanMetricReporter;
+import org.springframework.core.env.Environment;
 import org.springframework.integration.annotation.InboundChannelAdapter;
 import org.springframework.integration.annotation.MessageEndpoint;
 import org.springframework.integration.annotation.Poller;
@@ -41,7 +44,11 @@ import org.springframework.integration.annotation.Poller;
 @MessageEndpoint
 public class StreamSpanReporter implements SpanReporter {
 
-	private static final Log log = LogFactory.getLog(MethodHandles.lookup().lookupClass());
+	private static final org.apache.commons.logging.Log log = LogFactory.getLog(MethodHandles.lookup().lookupClass());
+
+	private static final List<String> RPC_EVENTS = Arrays.asList(
+			Span.CLIENT_RECV, Span.CLIENT_SEND, Span.SERVER_RECV, Span.SERVER_SEND
+	);
 
 	/**
 	 * Bean name for the
@@ -53,10 +60,19 @@ public class StreamSpanReporter implements SpanReporter {
 	private BlockingQueue<Span> queue = new LinkedBlockingQueue<>(1000);
 	private final HostLocator endpointLocator;
 	private final SpanMetricReporter spanMetricReporter;
+	private final Environment environment;
 
-	public StreamSpanReporter(HostLocator endpointLocator, SpanMetricReporter spanMetricReporter) {
+	@Deprecated
+	public StreamSpanReporter(HostLocator endpointLocator,
+			SpanMetricReporter spanMetricReporter) {
+		this(endpointLocator, spanMetricReporter, null);
+	}
+
+	public StreamSpanReporter(HostLocator endpointLocator,
+			SpanMetricReporter spanMetricReporter, Environment environment) {
 		this.endpointLocator = endpointLocator;
 		this.spanMetricReporter = spanMetricReporter;
+		this.environment = environment;
 	}
 
 	public void setQueue(BlockingQueue<Span> queue) {
@@ -84,6 +100,9 @@ public class StreamSpanReporter implements SpanReporter {
 	public void report(Span span) {
 		if (span.isExportable()) {
 			try {
+				if (this.environment != null) {
+					processLogs(span);
+				}
 				this.queue.add(span);
 			} catch (Exception e) {
 				this.spanMetricReporter.incrementDroppedSpans(1);
@@ -97,4 +116,13 @@ public class StreamSpanReporter implements SpanReporter {
 			}
 		}
 	}
+
+	private void processLogs(Span span) {
+		for (Log spanLog : span.logs()) {
+			if (RPC_EVENTS.contains(spanLog.getEvent())) {
+				span.tag(Span.INSTANCEID, IdUtils.getDefaultInstanceId(this.environment));
+			}
+		}
+	}
+
 }

spring-cloud-sleuth-stream/src/test/java/org/springframework/cloud/sleuth/stream/StreamSpanReporterTests.java

@@ -16,27 +16,34 @@
 
 package org.springframework.cloud.sleuth.stream;
 
+import java.util.Map;
 import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
 
+import org.junit.Before;
 import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.mockito.InjectMocks;
-import org.mockito.Mock;
-import org.mockito.runners.MockitoJUnitRunner;
+import org.mockito.Mockito;
 import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.metric.SpanMetricReporter;
+import org.springframework.mock.env.MockEnvironment;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.BDDMockito.then;
 
 /**
  * @author Marcin Grzejszczak
  */
-@RunWith(MockitoJUnitRunner.class)
 public class StreamSpanReporterTests {
 
-	@Mock HostLocator endpointLocator;
-	@Mock SpanMetricReporter spanMetricReporter;
-	@InjectMocks StreamSpanReporter reporter;
+	HostLocator endpointLocator = Mockito.mock(HostLocator.class);
+	SpanMetricReporter spanMetricReporter = Mockito.mock(SpanMetricReporter.class);
+	MockEnvironment mockEnvironment = new MockEnvironment();
+	StreamSpanReporter reporter;
+
+	@Before
+	public void setup() {
+		this.reporter = new StreamSpanReporter(this.endpointLocator, this.spanMetricReporter, this.mockEnvironment);
+	}
 
 	@Test
 	public void should_not_throw_an_exception_when_queue_size_is_exceeded() throws Exception {
@@ -46,7 +53,43 @@ public class StreamSpanReporterTests {
 
 		this.reporter.report(Span.builder().name("bar").exportable(true).build());
 
-		then(spanMetricReporter).should().incrementDroppedSpans(1);
+		then(this.spanMetricReporter).should().incrementDroppedSpans(1);
+	}
+
+	@Test
+	@SuppressWarnings("unchecked")
+	public void should_append_client_serviceid_when_span_has_rpc_event() throws Exception {
+		LinkedBlockingQueue<Span> queue = new LinkedBlockingQueue<>(1000);
+		this.reporter.setQueue(queue);
+		this.mockEnvironment.setProperty("vcap.application.instance_id", "foo");
+		Span span = Span.builder().name("bar").exportable(true).build();
+		span.logEvent(Span.CLIENT_RECV);
+
+		this.reporter.report(span);
+
+		assertThat(queue).isNotEmpty();
+		assertThat(queue.poll())
+				.extracting(Span::tags)
+				.extracting(o -> ((Map<String, String>) o).get(Span.INSTANCEID))
+				.containsExactly("foo");
+	}
+
+	@Test
+	@SuppressWarnings("unchecked")
+	public void should_not_append_server_serviceid_when_span_has_rpc_event_and_there_is_no_environment() throws Exception {
+		this.reporter = new StreamSpanReporter(this.endpointLocator, this.spanMetricReporter, null);
+		LinkedBlockingQueue<Span> queue = new LinkedBlockingQueue<>(1000);
+		this.reporter.setQueue(queue);
+		Span span = Span.builder().name("bar").exportable(true).build();
+		span.logEvent(Span.CLIENT_SEND);
+
+		this.reporter.report(span);
+
+		assertThat(queue).isNotEmpty();
+		assertThat(queue.poll())
+				.extracting(Span::tags)
+				.filteredOn(o -> ((Map<String, String>) o).containsKey(Span.INSTANCEID))
+				.isNullOrEmpty();
 	}
 
 }

spring-cloud-sleuth-zipkin/src/main/java/org/springframework/cloud/sleuth/zipkin/ZipkinAutoConfiguration.java

@@ -34,7 +34,7 @@ import org.springframework.cloud.sleuth.sampler.PercentageBasedSampler;
 import org.springframework.cloud.sleuth.sampler.SamplerProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
-
+import org.springframework.core.env.Environment;
 
 /**
  * {@link org.springframework.boot.autoconfigure.EnableAutoConfiguration Auto-configuration}
@@ -64,8 +64,9 @@ public class ZipkinAutoConfiguration {
 	}
 
 	@Bean
-	public SpanReporter zipkinSpanListener(ZipkinSpanReporter reporter, EndpointLocator endpointLocator) {
-		return new ZipkinSpanListener(reporter, endpointLocator);
+	public SpanReporter zipkinSpanListener(ZipkinSpanReporter reporter, EndpointLocator endpointLocator,
+			Environment environment) {
+		return new ZipkinSpanListener(reporter, endpointLocator, environment);
 	}
 
 	@Configuration

spring-cloud-sleuth-zipkin/src/main/java/org/springframework/cloud/sleuth/zipkin/ZipkinSpanListener.java

@@ -21,9 +21,11 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 
+import org.springframework.cloud.commons.util.IdUtils;
 import org.springframework.cloud.sleuth.Log;
 import org.springframework.cloud.sleuth.Span;
 import org.springframework.cloud.sleuth.SpanReporter;
+import org.springframework.core.env.Environment;
 import org.springframework.util.StringUtils;
 
 import zipkin.Annotation;
@@ -41,13 +43,17 @@ public class ZipkinSpanListener implements SpanReporter {
 	private static final List<String> ZIPKIN_START_EVENTS = Arrays.asList(
 			Constants.CLIENT_RECV, Constants.SERVER_RECV
 	);
+	private static final List<String> RPC_EVENTS = Arrays.asList(
+			Constants.CLIENT_RECV, Constants.CLIENT_SEND, Constants.SERVER_RECV, Constants.SERVER_SEND
+	);
 
 	private static final org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory
 			.getLog(ZipkinSpanListener.class);
 	private static final Charset UTF_8 = Charset.forName("UTF-8");
 	private static final byte[] UNKNOWN_BYTES = "unknown".getBytes(UTF_8);
 
-	private ZipkinSpanReporter reporter;
+	private final ZipkinSpanReporter reporter;
+	private final Environment environment;
 	/**
 	 * Endpoint is the visible IP address of this service, the port it is listening on and
 	 * the service name from discovery.
@@ -55,9 +61,16 @@ public class ZipkinSpanListener implements SpanReporter {
 	// Visible for testing
 	EndpointLocator endpointLocator;
 
+	@Deprecated
 	public ZipkinSpanListener(ZipkinSpanReporter reporter, EndpointLocator endpointLocator) {
+		this(reporter, endpointLocator, null);
+	}
+
+	public ZipkinSpanListener(ZipkinSpanReporter reporter, EndpointLocator endpointLocator,
+			Environment environment) {
 		this.reporter = reporter;
 		this.endpointLocator = endpointLocator;
+		this.environment = environment;
 	}
 
 	/**
@@ -76,15 +89,10 @@ public class ZipkinSpanListener implements SpanReporter {
 	zipkin.Span convert(Span span) {
 		zipkin.Span.Builder zipkinSpan = zipkin.Span.builder();
 
-		// A zipkin span without any annotations cannot be queried, add special "lc" to avoid that.
-		if (notClientOrServer(span)) {
-			ensureLocalComponent(span, zipkinSpan);
-		}
-		addZipkinAnnotations(zipkinSpan, span, this.endpointLocator.local());
-		addZipkinBinaryAnnotations(zipkinSpan, span, this.endpointLocator.local());
-		if (hasClientSend(span)) {
-			ensureServerAddr(span, zipkinSpan);
-		}
+		Endpoint endpoint = this.endpointLocator.local();
+		processLogs(span, zipkinSpan, endpoint);
+		addZipkinAnnotations(zipkinSpan, span, endpoint);
+		addZipkinBinaryAnnotations(zipkinSpan, span, endpoint);
 		// In the RPC span model, the client owns the timestamp and duration of the span. If we
 		// were propagated an id, we can assume that we shouldn't report timestamp or duration,
 		// rather let the client do that. Worst case we were propagated an unreported ID and
@@ -134,22 +142,40 @@ public class ZipkinSpanListener implements SpanReporter {
 		}
 	}
 
-	private boolean notClientOrServer(Span span) {
+	// Instead of going through the list of logs multiple times we're doing it only once
+	private void processLogs(Span span, zipkin.Span.Builder zipkinSpan, Endpoint endpoint) {
+		boolean notClientOrServer = true;
+		boolean hasClientSend = false;
+		boolean instanceIdToTag = false;
 		for (Log log : span.logs()) {
+			if (RPC_EVENTS.contains(log.getEvent())) {
+				instanceIdToTag = true;
+			}
 			if (ZIPKIN_START_EVENTS.contains(log.getEvent())) {
-				return false;
+				notClientOrServer = false;
+			}
+			if (Constants.CLIENT_SEND.equals(log.getEvent())) {
+				hasClientSend = !span.tags().containsKey(Constants.SERVER_ADDR);
 			}
 		}
-		return true;
+		if (notClientOrServer) {
+			// A zipkin span without any annotations cannot be queried, add special "lc" to avoid that.
+			ensureLocalComponent(span, zipkinSpan);
+		}
+		if (hasClientSend) {
+			ensureServerAddr(span, zipkinSpan);
+		}
+		if (instanceIdToTag && this.environment != null) {
+			setInstanceIdIfPresent(zipkinSpan, endpoint, Span.INSTANCEID);
+		}
 	}
 
-	private boolean hasClientSend(Span span) {
-		for (Log log : span.logs()) {
-			if (Constants.CLIENT_SEND.equals(log.getEvent())) {
-				return !span.tags().containsKey(Constants.SERVER_ADDR);
-			}
+	private void setInstanceIdIfPresent(zipkin.Span.Builder zipkinSpan,
+			Endpoint endpoint, String key) {
+		String property = IdUtils.getDefaultInstanceId(this.environment);
+		if (StringUtils.hasText(property)) {
+			addZipkinBinaryAnnotation(key, property, endpoint, zipkinSpan);
 		}
-		return false;
 	}
 
 	/**
@@ -172,15 +198,20 @@ public class ZipkinSpanListener implements SpanReporter {
 	private void addZipkinBinaryAnnotations(zipkin.Span.Builder zipkinSpan,
 			Span span, Endpoint ep) {
 		for (Map.Entry<String, String> e : span.tags().entrySet()) {
-			BinaryAnnotation binaryAnn = BinaryAnnotation.builder()
-					.type(BinaryAnnotation.Type.STRING)
-					.key(e.getKey())
-					.value(e.getValue().getBytes(UTF_8))
-					.endpoint(ep).build();
-			zipkinSpan.addBinaryAnnotation(binaryAnn);
+			addZipkinBinaryAnnotation(e.getKey(), e.getValue(), ep, zipkinSpan);
 		}
 	}
 
+	private void addZipkinBinaryAnnotation(String key, String value, Endpoint ep,
+			zipkin.Span.Builder zipkinSpan) {
+		BinaryAnnotation binaryAnn = BinaryAnnotation.builder()
+				.type(BinaryAnnotation.Type.STRING)
+				.key(key)
+				.value(value.getBytes(UTF_8))
+				.endpoint(ep).build();
+		zipkinSpan.addBinaryAnnotation(binaryAnn);
+	}
+
 	/**
 	 * There could be instrumentation delay between span creation and the
 	 * semantic start of the span (client send). When there's a difference,

spring-cloud-sleuth-zipkin/src/test/java/org/springframework/cloud/sleuth/zipkin/ZipkinSpanListenerTests.java

@@ -34,6 +34,8 @@ import org.springframework.cloud.sleuth.zipkin.ZipkinSpanListenerTests.TestConfi
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Primary;
+import org.springframework.mock.env.MockEnvironment;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 
 import zipkin.Constants;
@@ -52,7 +54,10 @@ public class ZipkinSpanListenerTests {
 	@Autowired Tracer tracer;
 	@Autowired ApplicationContext application;
 	@Autowired TestConfiguration test;
-	@Autowired ZipkinSpanListener spanReporter;
+	@Autowired ZipkinSpanListener spanListener;
+	@Autowired ZipkinSpanReporter spanReporter;
+	@Autowired MockEnvironment mockEnvironment;
+	@Autowired EndpointLocator endpointLocator;
 
 	@PostConstruct
 	public void init() {
@@ -69,7 +74,7 @@ public class ZipkinSpanListenerTests {
 		span.logEvent("hystrix/retry"); // System.currentTimeMillis
 		span.stop();
 
-		zipkin.Span result = this.spanReporter.convert(span);
+		zipkin.Span result = this.spanListener.convert(span);
 
 		assertThat(result.timestamp)
 				.isEqualTo(span.getBegin() * 1000);
@@ -90,7 +95,7 @@ public class ZipkinSpanListenerTests {
 		Thread.sleep(20);
 		span.stop();
 
-		zipkin.Span result = this.spanReporter.convert(span);
+		zipkin.Span result = this.spanListener.convert(span);
 
 		assertThat(result.timestamp)
 				.isEqualTo(span.getBegin() * 1000);
@@ -107,7 +112,7 @@ public class ZipkinSpanListenerTests {
 	@Test
 	public void doesntSetDurationWhenStillRunning() {
 		Span span = Span.builder().traceId(1L).name("http:api").build();
-		zipkin.Span result = this.spanReporter.convert(span);
+		zipkin.Span result = this.spanListener.convert(span);
 
 		assertThat(result.timestamp)
 				.isGreaterThan(0); // sanity check it did start
@@ -124,7 +129,7 @@ public class ZipkinSpanListenerTests {
 	@Test
 	public void doesntSetTimestampOrDurationWhenRemote() {
 		this.parent.stop();
-		zipkin.Span result = this.spanReporter.convert(this.parent);
+		zipkin.Span result = this.spanListener.convert(this.parent);
 
 		assertThat(result.timestamp)
 				.isNull();
@@ -138,10 +143,10 @@ public class ZipkinSpanListenerTests {
 		this.parent.logEvent("hystrix/retry");
 		this.parent.tag("spring-boot/version", "1.3.1.RELEASE");
 
-		zipkin.Span result = this.spanReporter.convert(this.parent);
+		zipkin.Span result = this.spanListener.convert(this.parent);
 
 		assertThat(result.annotations.get(0).endpoint)
-				.isEqualTo(this.spanReporter.endpointLocator.local());
+				.isEqualTo(this.spanListener.endpointLocator.local());
 		assertThat(result.binaryAnnotations.get(0).endpoint)
 				.isEqualTo(result.annotations.get(0).endpoint);
 	}
@@ -149,7 +154,7 @@ public class ZipkinSpanListenerTests {
 	/** zipkin's Endpoint.serviceName should never be null. */
 	@Test
 	public void localEndpointIncludesServiceName() {
-		assertThat(this.spanReporter.endpointLocator.local().serviceName)
+		assertThat(this.spanListener.endpointLocator.local().serviceName)
 				.isNotEmpty();
 	}
 
@@ -172,7 +177,7 @@ public class ZipkinSpanListenerTests {
 		Span context = this.tracer.createSpan("http:child", this.parent);
 		context.logEvent(Span.CLIENT_SEND);
 		logServerReceived(this.parent);
-		logServerSent(this.spanReporter, this.parent);
+		logServerSent(this.spanListener, this.parent);
 		this.tracer.close(context);
 		assertEquals(2, this.test.zipkinSpans.size());
 	}
@@ -195,7 +200,7 @@ public class ZipkinSpanListenerTests {
 		this.parent.logEvent("hystrix/retry");
 		this.parent.stop();
 
-		zipkin.Span result = this.spanReporter.convert(this.parent);
+		zipkin.Span result = this.spanListener.convert(this.parent);
 
 		assertThat(result.binaryAnnotations)
 				.extracting(input -> input.key)
@@ -208,7 +213,7 @@ public class ZipkinSpanListenerTests {
 		this.parent.tag(Span.SPAN_PEER_SERVICE_TAG_NAME, "fooservice");
 		this.parent.stop();
 
-		zipkin.Span result = this.spanReporter.convert(this.parent);
+		zipkin.Span result = this.spanListener.convert(this.parent);
 
 		assertThat(result.binaryAnnotations)
 				.filteredOn("key", Constants.SERVER_ADDR)
@@ -220,7 +225,7 @@ public class ZipkinSpanListenerTests {
 		this.parent.logEvent(Constants.CLIENT_SEND);
 		this.parent.stop();
 
-		zipkin.Span result = this.spanReporter.convert(this.parent);
+		zipkin.Span result = this.spanListener.convert(this.parent);
 
 		assertThat(result.binaryAnnotations)
 				.filteredOn("key", Constants.SERVER_ADDR)
@@ -231,7 +236,7 @@ public class ZipkinSpanListenerTests {
 	public void converts128BitTraceId() {
 		Span span = Span.builder().traceIdHigh(1L).traceId(2L).spanId(3L).name("foo").build();
 
-		zipkin.Span result = this.spanReporter.convert(span);
+		zipkin.Span result = this.spanListener.convert(span);
 
 		assertThat(result.traceIdHigh).isEqualTo(span.getTraceIdHigh());
 		assertThat(result.traceId).isEqualTo(span.getTraceId());
@@ -243,7 +248,7 @@ public class ZipkinSpanListenerTests {
 		this.parent.tag(Span.SPAN_PEER_SERVICE_TAG_NAME, "fooservice");
 		this.parent.stop();
 
-		zipkin.Span result = this.spanReporter.convert(this.parent);
+		zipkin.Span result = this.spanListener.convert(this.parent);
 
 		assertThat(result.binaryAnnotations)
 				.filteredOn("key", Constants.SERVER_ADDR)
@@ -255,11 +260,38 @@ public class ZipkinSpanListenerTests {
 	public void shouldNotReportToZipkinWhenSpanIsNotExportable() {
 		Span span = Span.builder().exportable(false).build();
 
-		this.spanReporter.report(span);
+		this.spanListener.report(span);
 
 		assertThat(this.test.zipkinSpans).isEmpty();
 	}
 
+	@Test
+	public void shouldAddClientServiceIdTagWhenSpanContainsRpcEvent() {
+		this.parent.logEvent(Span.CLIENT_SEND);
+		this.mockEnvironment.setProperty("vcap.application.instance_id", "foo");
+
+		zipkin.Span result = this.spanListener.convert(this.parent);
+
+		assertThat(result.binaryAnnotations)
+				.filteredOn("key", Span.INSTANCEID)
+				.extracting(input -> input.value)
+				.containsOnly("foo".getBytes());
+	}
+
+	@Test
+	public void shouldNotAddAnyServiceIdTagWhenSpanContainsRpcEventAndThereIsNoEnvironment() {
+		this.parent.logEvent(Span.CLIENT_RECV);
+		ZipkinSpanListener spanListener = new ZipkinSpanListener(this.spanReporter,
+				this.endpointLocator, null);
+
+		zipkin.Span result = spanListener.convert(this.parent);
+
+		assertThat(result.binaryAnnotations)
+				.filteredOn("key", Span.INSTANCEID)
+				.extracting(input -> input.value)
+				.isEmpty();
+	}
+
 	@Configuration
 	@EnableAutoConfiguration
 	protected static class TestConfiguration {
@@ -276,6 +308,10 @@ public class ZipkinSpanListenerTests {
 			return this.zipkinSpans::add;
 		}
 
+		@Bean @Primary MockEnvironment mockEnvironment() {
+			return new MockEnvironment();
+		}
+
 	}
 
 }