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new dc99f88d076 HADOOP-19920. Fix flaky test TestPrometheusMetricsSink
(#8549)
dc99f88d076 is described below
commit dc99f88d076346e5a7d959131640040adf7c3837
Author: Cheng Pan <[email protected]>
AuthorDate: Tue Jun 16 19:32:57 2026 +0800
HADOOP-19920. Fix flaky test TestPrometheusMetricsSink (#8549)
Reviewed-by: Aaron Fabbri <[email protected]>
Reviewed-by: Shilun Fan <[email protected]>
Signed-off-by: Cheng Pan <[email protected]>
---
.../metrics2/sink/TestPrometheusMetricsSink.java | 77 +++++++++++-----------
1 file changed, 40 insertions(+), 37 deletions(-)
diff --git
a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/metrics2/sink/TestPrometheusMetricsSink.java
b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/metrics2/sink/TestPrometheusMetricsSink.java
index 5abdff6c142..90e612001ff 100644
---
a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/metrics2/sink/TestPrometheusMetricsSink.java
+++
b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/metrics2/sink/TestPrometheusMetricsSink.java
@@ -35,7 +35,11 @@
import org.apache.hadoop.metrics2.lib.Interns;
import org.apache.hadoop.metrics2.lib.MutableCounterLong;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
import static java.nio.charset.StandardCharsets.UTF_8;
import static org.assertj.core.api.Assertions.assertThat;
@@ -48,12 +52,37 @@
*/
public class TestPrometheusMetricsSink {
+ private static final Logger LOG =
+ LoggerFactory.getLogger(TestPrometheusMetricsSink.class);
+
+ /**
+ * Shared {@code DefaultMetricsSystem} singleton, set up fresh per test.
+ * Each test does exactly one balanced {@code init}/{@code shutdown} so the
+ * system (and the JVM-global source-name registry it owns) is fully reset
+ * between tests. This keeps tests isolated even when an assertion fails
+ * before the test body finishes, avoiding flaky failures such as
+ * "Metrics source TestMetrics already exists!" on later tests or reruns.
+ */
+ private MetricsSystem metrics;
+
+ @BeforeEach
+ public void setUp() {
+ metrics = DefaultMetricsSystem.instance();
+ metrics.init("test");
+ }
+
+ @AfterEach
+ public void tearDown() {
+ // DefaultMetricsSystem.shutdown() shuts down the underlying metrics system
+ // and, once its refCount reaches 0, clears the JVM-global source-name and
+ // MBean-name registries. Running it in @AfterEach guarantees cleanup even
+ // when a test assertion fails before reaching the end of the test body.
+ DefaultMetricsSystem.shutdown();
+ }
+
@Test
public void testPublish() throws IOException {
//GIVEN
- MetricsSystem metrics = DefaultMetricsSystem.instance();
-
- metrics.init("test");
PrometheusMetricsSink sink = new PrometheusMetricsSink();
metrics.register("Prometheus", "Prometheus", sink);
TestMetrics testMetrics = metrics
@@ -69,14 +98,10 @@ public void testPublish() throws IOException {
writer.flush();
//THEN
- String writtenMetrics = stream.toString(UTF_8.name());
- System.out.println(writtenMetrics);
+ String writtenMetrics = stream.toString(UTF_8);
+ LOG.debug(writtenMetrics);
assertTrue(writtenMetrics.contains("test_metrics_num_bucket_create_fails{context=\"dfs\""),
"The expected metric line is missing from prometheus metrics output");
-
- metrics.unregisterSource("TestMetrics");
- metrics.stop();
- metrics.shutdown();
}
/**
@@ -86,9 +111,6 @@ public void testPublish() throws IOException {
@Test
public void testPublishMultiple() throws IOException {
//GIVEN
- MetricsSystem metrics = DefaultMetricsSystem.instance();
-
- metrics.init("test");
PrometheusMetricsSink sink = new PrometheusMetricsSink();
metrics.register("Prometheus", "Prometheus", sink);
TestMetrics testMetrics1 = metrics
@@ -107,19 +129,14 @@ public void testPublishMultiple() throws IOException {
writer.flush();
//THEN
- String writtenMetrics = stream.toString(UTF_8.name());
- System.out.println(writtenMetrics);
+ String writtenMetrics = stream.toString(UTF_8);
+ LOG.debug(writtenMetrics);
assertTrue(writtenMetrics.contains(
"test_metrics_num_bucket_create_fails{context=\"dfs\",testtag=\"testTagValue1\""),
"The expected first metric line is missing from prometheus metrics
output");
assertTrue(writtenMetrics.contains(
"test_metrics_num_bucket_create_fails{context=\"dfs\",testtag=\"testTagValue2\""),
"The expected second metric line is missing from prometheus metrics
output");
-
- metrics.unregisterSource("TestMetrics1");
- metrics.unregisterSource("TestMetrics2");
- metrics.stop();
- metrics.shutdown();
}
/**
@@ -128,9 +145,6 @@ public void testPublishMultiple() throws IOException {
@Test
public void testPublishFlush() throws IOException {
//GIVEN
- MetricsSystem metrics = DefaultMetricsSystem.instance();
-
- metrics.init("test");
PrometheusMetricsSink sink = new PrometheusMetricsSink();
metrics.register("Prometheus", "Prometheus", sink);
TestMetrics testMetrics = metrics
@@ -154,18 +168,14 @@ public void testPublishFlush() throws IOException {
writer.flush();
//THEN
- String writtenMetrics = stream.toString(UTF_8.name());
- System.out.println(writtenMetrics);
+ String writtenMetrics = stream.toString(UTF_8);
+ LOG.debug(writtenMetrics);
assertFalse(writtenMetrics.contains(
"test_metrics_num_bucket_create_fails{context=\"dfs\",testtag=\"testTagValue1\""),
"The first metric should not exist after flushing");
assertTrue(writtenMetrics.contains(
"test_metrics_num_bucket_create_fails{context=\"dfs\",testtag=\"testTagValue2\""),
"The expected metric line is missing from prometheus metrics output");
-
- metrics.unregisterSource("TestMetrics");
- metrics.stop();
- metrics.shutdown();
}
@Test
@@ -223,10 +233,6 @@ public void testNamingWhitespaces() {
*/
@Test
public void testTopMetricsPublish() throws IOException {
- MetricsSystem metrics = DefaultMetricsSystem.instance();
-
- metrics.init("test");
-
//GIVEN
PrometheusMetricsSink sink = new PrometheusMetricsSink();
@@ -248,8 +254,8 @@ public void testTopMetricsPublish() throws IOException {
writer.flush();
//THEN
- String writtenMetrics = stream.toString(UTF_8.name());
- System.out.println(writtenMetrics);
+ String writtenMetrics = stream.toString(UTF_8);
+ LOG.debug(writtenMetrics);
assertThat(writtenMetrics)
.contains(
@@ -260,9 +266,6 @@ public void testTopMetricsPublish() throws IOException {
"nn_top_user_op_counts_window_ms_1500000_count{")
.contains(
"op=\"rename\",user=\"hadoop/[email protected]\"");
-
- metrics.stop();
- metrics.shutdown();
}
/**
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