From b8db95bc78c4ddfd8419acb3eb48c9d3070e725f Mon Sep 17 00:00:00 2001
From: Marcin Grzejszczak <marcin@grzejszczak.pl>
Date: Tue, 11 Oct 2016 15:15:11 +0200
Subject: [PATCH] Not throwing an exception when queue size is exceeded

without this change when queue size of spans is exceeded for Stream span propagation, an exception is thrown that terminates business logic processing
with this change we're not propagating the exception - we're incrementing the dropped spans counter

fixes #421
---
 .../sleuth/stream/StreamSpanReporter.java     |  9 +++-
 .../stream/StreamSpanReporterTests.java       | 52 +++++++++++++++++++
 2 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 spring-cloud-sleuth-stream/src/test/java/org/springframework/cloud/sleuth/stream/StreamSpanReporterTests.java

diff --git a/spring-cloud-sleuth-stream/src/main/java/org/springframework/cloud/sleuth/stream/StreamSpanReporter.java b/spring-cloud-sleuth-stream/src/main/java/org/springframework/cloud/sleuth/stream/StreamSpanReporter.java
index 935b789be..3ddcbeade 100644
--- a/spring-cloud-sleuth-stream/src/main/java/org/springframework/cloud/sleuth/stream/StreamSpanReporter.java
+++ b/spring-cloud-sleuth-stream/src/main/java/org/springframework/cloud/sleuth/stream/StreamSpanReporter.java
@@ -83,7 +83,14 @@ public class StreamSpanReporter implements SpanReporter {
 	@Override
 	public void report(Span span) {
 		if (span.isExportable()) {
-			this.queue.add(span);
+			try {
+				this.queue.add(span);
+			} catch (Exception e) {
+				this.spanMetricReporter.incrementDroppedSpans(1);
+				if (log.isDebugEnabled()) {
+					log.debug("The span " + span + " will not be sent to Zipkin due to [" + e + "]");
+				}
+			}
 		} else {
 			if (log.isDebugEnabled()) {
 				log.debug("The span " + span + " will not be sent to Zipkin due to sampling");
diff --git a/spring-cloud-sleuth-stream/src/test/java/org/springframework/cloud/sleuth/stream/StreamSpanReporterTests.java b/spring-cloud-sleuth-stream/src/test/java/org/springframework/cloud/sleuth/stream/StreamSpanReporterTests.java
new file mode 100644
index 000000000..49c5402bf
--- /dev/null
+++ b/spring-cloud-sleuth-stream/src/test/java/org/springframework/cloud/sleuth/stream/StreamSpanReporterTests.java
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2013-2016 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.sleuth.stream;
+
+import java.util.concurrent.ArrayBlockingQueue;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
+import org.springframework.cloud.sleuth.Span;
+import org.springframework.cloud.sleuth.metric.SpanMetricReporter;
+
+import static org.mockito.BDDMockito.then;
+
+/**
+ * @author Marcin Grzejszczak
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class StreamSpanReporterTests {
+
+	@Mock HostLocator endpointLocator;
+	@Mock SpanMetricReporter spanMetricReporter;
+	@InjectMocks StreamSpanReporter reporter;
+
+	@Test
+	public void should_not_throw_an_exception_when_queue_size_is_exceeded() throws Exception {
+		ArrayBlockingQueue<Span> queue = new ArrayBlockingQueue<>(1);
+		queue.add(Span.builder().name("foo").build());
+		this.reporter.setQueue(queue);
+
+		this.reporter.report(Span.builder().name("bar").exportable(true).build());
+
+		then(spanMetricReporter).should().incrementDroppedSpans(1);
+	}
+
+}
\ No newline at end of file