[HUDI-1149] Added a console metrics reporter and associated unit tests.

hudi-client/src/main/java/org/apache/hudi/metrics/ConsoleMetricsReporter.java

@@ -0,0 +1,72 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.hudi.metrics;
+
+import java.io.Closeable;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.log4j.LogManager;
+import org.apache.log4j.Logger;
+
+import com.codahale.metrics.ConsoleReporter;
+import com.codahale.metrics.MetricFilter;
+import com.codahale.metrics.MetricRegistry;
+
+/**
+ * Hudi Console metrics reporter. Reports the metrics by printing them to the stdout on the console.
+ */
+public class ConsoleMetricsReporter extends MetricsReporter {
+
+  private static final Logger LOG = LogManager.getLogger(ConsoleMetricsReporter.class);
+  private final ConsoleReporter consoleReporter;
+
+  public ConsoleMetricsReporter(MetricRegistry registry) {
+    this.consoleReporter = ConsoleReporter.forRegistry(registry)
+        .convertRatesTo(TimeUnit.SECONDS)
+        .convertDurationsTo(TimeUnit.MILLISECONDS)
+        .filter(MetricFilter.ALL).build();
+  }
+
+  @Override
+  public void start() {
+    if (consoleReporter != null) {
+      consoleReporter.start(30, TimeUnit.SECONDS);
+    } else {
+      LOG.error("Cannot start as the consoleReporter is null.");
+    }
+  }
+
+  @Override
+  public void report() {
+    if (consoleReporter != null) {
+      consoleReporter.report();
+    } else {
+      LOG.error("Cannot report metrics as the consoleReporter is null.");
+    }
+  }
+
+  @Override
+  public Closeable getReporter() {
+    return consoleReporter;
+  }
+
+  @Override
+  public void stop() {
+  }
+}

hudi-client/src/main/java/org/apache/hudi/metrics/MetricsReporterFactory.java

@@ -66,6 +66,9 @@ public class MetricsReporterFactory {
       case DATADOG:
         reporter = new DatadogMetricsReporter(config, registry);
         break;
+      case CONSOLE:
+        reporter = new ConsoleMetricsReporter(registry);
+        break;
       default:
         LOG.error("Reporter type[" + type + "] is not supported.");
         break;

hudi-client/src/main/java/org/apache/hudi/metrics/MetricsReporterType.java

@@ -22,5 +22,5 @@ package org.apache.hudi.metrics;
  * Types of the reporter. Right now we only support Graphite. We can include JMX and CSV in the future.
  */
 public enum MetricsReporterType {
-  GRAPHITE, INMEMORY, JMX, DATADOG
+  GRAPHITE, INMEMORY, JMX, DATADOG, CONSOLE
 }

hudi-client/src/test/java/org/apache/hudi/metrics/TestHoodieConsoleMetrics.java

@@ -0,0 +1,46 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.hudi.metrics;
+
+import org.apache.hudi.config.HoodieWriteConfig;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.apache.hudi.metrics.Metrics.registerGauge;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class TestHoodieConsoleMetrics {
+
+  HoodieWriteConfig config = mock(HoodieWriteConfig.class);
+
+  @BeforeEach
+  public void start() {
+    when(config.isMetricsOn()).thenReturn(true);
+    when(config.getMetricsReporterType()).thenReturn(MetricsReporterType.CONSOLE);
+    new HoodieMetrics(config, "raw_table");
+  }
+
+  @Test
+  public void testRegisterGauge() {
+    registerGauge("metric1", 123L);
+    assertEquals("123", Metrics.getInstance().getRegistry().getGauges().get("metric1").getValue().toString());
+  }
+}