HADOOP-13439. Fix race between TestMetricsSystemImpl and TestGangliaMetrics. Contributed by Chen Liang.

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/metrics2/impl/TestGangliaMetrics.java

@@ -50,23 +50,28 @@ import org.junit.Test;
 
 public class TestGangliaMetrics {
   public static final Log LOG = LogFactory.getLog(TestMetricsSystemImpl.class);
-  private final String[] expectedMetrics =
-    { "test.s1rec.C1",
-      "test.s1rec.G1",
-      "test.s1rec.Xxx",
-      "test.s1rec.Yyy",
-      "test.s1rec.S1NumOps",
-      "test.s1rec.S1AvgTime" };
+  // This is the prefix to locate the config file for this particular test
+  // This is to avoid using the same config file with other test cases,
+  // which can cause race conditions.
+  private String testNamePrefix = "gangliametrics";
+  private final String[] expectedMetrics = {
+      testNamePrefix + ".s1rec.C1",
+      testNamePrefix + ".s1rec.G1",
+      testNamePrefix + ".s1rec.Xxx",
+      testNamePrefix + ".s1rec.Yyy",
+      testNamePrefix + ".s1rec.S1NumOps",
+      testNamePrefix + ".s1rec.S1AvgTime"
+  };
 
   @Test
   public void testTagsForPrefix() throws Exception {
     ConfigBuilder cb = new ConfigBuilder()
-      .add("test.sink.ganglia.tagsForPrefix.all", "*")
-      .add("test.sink.ganglia.tagsForPrefix.some", "NumActiveSinks, " +
-              "NumActiveSources")
-      .add("test.sink.ganglia.tagsForPrefix.none", "");
+        .add(testNamePrefix + ".sink.ganglia.tagsForPrefix.all", "*")
+        .add(testNamePrefix + ".sink.ganglia.tagsForPrefix.some",
+          "NumActiveSinks, " + "NumActiveSources")
+        .add(testNamePrefix + ".sink.ganglia.tagsForPrefix.none", "");
     GangliaSink30 sink = new GangliaSink30();
-    sink.init(cb.subset("test.sink.ganglia"));
+    sink.init(cb.subset(testNamePrefix + ".sink.ganglia"));
 
     List<MetricsTag> tags = new ArrayList<MetricsTag>();
     tags.add(new MetricsTag(MsInfo.Context, "all"));
@@ -101,11 +106,14 @@ public class TestGangliaMetrics {
     // Setting long interval to avoid periodic publishing.
     // We manually publish metrics by MeticsSystem#publishMetricsNow here.
     ConfigBuilder cb = new ConfigBuilder().add("*.period", 120)
-        .add("test.sink.gsink30.context", "test") // filter out only "test"
-        .add("test.sink.gsink31.context", "test") // filter out only "test"
-        .save(TestMetricsConfig.getTestFilename("hadoop-metrics2-test"));
-
-    MetricsSystemImpl ms = new MetricsSystemImpl("Test");
+        .add(testNamePrefix
+            + ".sink.gsink30.context", testNamePrefix) // filter out only "test"
+        .add(testNamePrefix
+            + ".sink.gsink31.context", testNamePrefix) // filter out only "test"
+        .save(TestMetricsConfig.getTestFilename("hadoop-metrics2-"
+            + testNamePrefix));
+
+    MetricsSystemImpl ms = new MetricsSystemImpl(testNamePrefix);
     ms.start();
     TestSource s1 = ms.register("s1", "s1 desc", new TestSource("s1rec"));
     s1.c1.incr();
@@ -119,13 +127,13 @@ public class TestGangliaMetrics {
 
     // Setup test for GangliaSink30
     AbstractGangliaSink gsink30 = new GangliaSink30();
-    gsink30.init(cb.subset("test"));
+    gsink30.init(cb.subset(testNamePrefix));
     MockDatagramSocket mockds30 = new MockDatagramSocket();
     GangliaMetricsTestHelper.setDatagramSocket(gsink30, mockds30);
 
     // Setup test for GangliaSink31
     AbstractGangliaSink gsink31 = new GangliaSink31();
-    gsink31.init(cb.subset("test"));
+    gsink31.init(cb.subset(testNamePrefix));
     MockDatagramSocket mockds31 = new MockDatagramSocket();
     GangliaMetricsTestHelper.setDatagramSocket(gsink31, mockds31);
 
@@ -168,7 +176,7 @@ public class TestGangliaMetrics {
   }
 
   @SuppressWarnings("unused")
-  @Metrics(context="test")
+  @Metrics(context="gangliametrics")
   private static class TestSource {
     @Metric("C1 desc") MutableCounterLong c1;
     @Metric("XXX desc") MutableCounterLong xxx;