Ensure sampler is called with the new span if it is to be started

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

@@ -71,14 +71,18 @@ public class DefaultTracer implements Tracer {
 	@Override
 	public Span startTrace(String name, Sampler sampler) {
 		Span span;
-		if (isTracing() || sampler.isSampled(getCurrentSpan())) {
+		if (isTracing()) {
 			span = createChild(getCurrentSpan(), name);
 		}
 		else {
-			// Non-exportable so we keep the trace but not other data
 			long id = createId();
 			span = Span.builder().begin(System.currentTimeMillis()).name(name).traceId(id)
-					.spanId(id).exportable(false).build();
+					.spanId(id).build();
+			if (!sampler.isSampled(span)) {
+				// Non-exportable so we keep the trace but not other data
+				span = Span.builder().begin(span.getBegin()).name(name).traceId(id)
+						.spanId(id).exportable(false).build();
+			}
 			this.publisher.publishEvent(new SpanAcquiredEvent(this, span));
 		}
 		return continueSpan(span);

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-stream/src/main/resources/application.yml

@@ -4,3 +4,6 @@ server:
 spring:
   application:
     name: testSleuthApp
+  sleuth:
+    sampler:
+      percentage: 1.0

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-zipkin/src/main/java/sample/SampleController.java

@@ -16,8 +16,9 @@
 
 package sample;
 
-import lombok.SneakyThrows;
-import lombok.extern.slf4j.Slf4j;
+import java.util.Random;
+import java.util.concurrent.Callable;
+
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerInitializedEvent;
 import org.springframework.cloud.sleuth.Span;
@@ -29,8 +30,8 @@ import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.client.RestTemplate;
 
-import java.util.Random;
-import java.util.concurrent.Callable;
+import lombok.SneakyThrows;
+import lombok.extern.slf4j.Slf4j;
 
 /**
  * @author Spencer Gibb
@@ -55,7 +56,7 @@ ApplicationListener<EmbeddedServletContainerInitializedEvent> {
 	@RequestMapping("/")
 	public String hi() {
 		Thread.sleep(this.random.nextInt(1000));
-
+		log.info("Home page");
 		String s = this.restTemplate.getForObject("http://localhost:" + this.port
 				+ "/hi2", String.class);
 		return "hi/" + s;
@@ -77,6 +78,7 @@ ApplicationListener<EmbeddedServletContainerInitializedEvent> {
 
 	@RequestMapping("/async")
 	public String async() {
+		log.info("async");
 		this.controller.background();
 		return "ho";
 	}
@@ -84,6 +86,7 @@ ApplicationListener<EmbeddedServletContainerInitializedEvent> {
 	@SneakyThrows
 	@RequestMapping("/hi2")
 	public String hi2() {
+		log.info("hi2");
 		int millis = this.random.nextInt(1000);
 		Thread.sleep(millis);
 		this.tracer.addTag("random-sleep-millis", String.valueOf(millis));

spring-cloud-sleuth-samples/spring-cloud-sleuth-sample-zipkin/src/main/resources/application.yml

@@ -8,6 +8,9 @@ spring:
   zipkin:
     # Uncomment to send to zipkin, replacing 192.168.99.100 with your zipkin IP address
     # baseUrl: http://192.168.99.100:9411/
+  sleuth:
+    sampler:
+      percentage: 1.0
 
 sample:
   zipkin: