ratis-metrics-default
org.apache.ratis
diff --git a/ratis-assembly/src/main/assembly/bin.xml b/ratis-assembly/src/main/assembly/bin.xml
index 85c14fc33b..f7e9cb5175 100644
--- a/ratis-assembly/src/main/assembly/bin.xml
+++ b/ratis-assembly/src/main/assembly/bin.xml
@@ -41,6 +41,7 @@
org.apache.ratis:ratis-test
org.apache.ratis:ratis-metrics-api
org.apache.ratis:ratis-metrics-default
+ org.apache.ratis:ratis-metrics-dropwizard3
org.apache.ratis:ratis-tools
org.apache.ratis:ratis-resource-bundle
diff --git a/ratis-assembly/src/main/assembly/src.xml b/ratis-assembly/src/main/assembly/src.xml
index 6b001af63c..9559917a0f 100644
--- a/ratis-assembly/src/main/assembly/src.xml
+++ b/ratis-assembly/src/main/assembly/src.xml
@@ -44,6 +44,7 @@
org.apache.ratis:ratis-test
org.apache.ratis:ratis-metrics-api
org.apache.ratis:ratis-metrics-default
+ org.apache.ratis:ratis-metrics-dropwizard3
org.apache.ratis:ratis-tools
org.apache.ratis:ratis-resource-bundle
diff --git a/ratis-metrics-default/src/test/java/org/apache/ratis/metrics/TestMetricRegistriesLoader.java b/ratis-metrics-default/src/test/java/org/apache/ratis/metrics/TestMetricRegistriesLoader.java
index cbfa6810c6..d06dec8ff2 100644
--- a/ratis-metrics-default/src/test/java/org/apache/ratis/metrics/TestMetricRegistriesLoader.java
+++ b/ratis-metrics-default/src/test/java/org/apache/ratis/metrics/TestMetricRegistriesLoader.java
@@ -21,20 +21,21 @@
import static org.junit.Assert.assertNotEquals;
import static org.mockito.Mockito.mock;
-import org.apache.ratis.thirdparty.com.google.common.collect.Lists;
+import org.apache.ratis.metrics.impl.MetricRegistriesImpl;
+import org.junit.Assert;
import org.junit.Test;
+import java.util.Arrays;
+import java.util.Collections;
/**
* Test class for {@link MetricRegistriesLoader}.
*/
public class TestMetricRegistriesLoader {
-
-
@Test
- public void testLoadSinleInstance() {
+ public void testLoadSingleInstance() {
MetricRegistries loader = mock(MetricRegistries.class);
- MetricRegistries instance = MetricRegistriesLoader.load(Lists.newArrayList(loader));
+ MetricRegistries instance = MetricRegistriesLoader.load(Collections.singletonList(loader));
assertEquals(loader, instance);
}
@@ -43,12 +44,18 @@ public void testLoadMultipleInstances() {
MetricRegistries loader1 = mock(MetricRegistries.class);
MetricRegistries loader2 = mock(MetricRegistries.class);
MetricRegistries loader3 = mock(MetricRegistries.class);
- MetricRegistries instance = MetricRegistriesLoader.load(Lists.newArrayList(loader1, loader2,
- loader3));
+ MetricRegistries instance = MetricRegistriesLoader.load(Arrays.asList(loader1, loader2, loader3));
// the load() returns the first instance
assertEquals(loader1, instance);
assertNotEquals(loader2, instance);
assertNotEquals(loader3, instance);
}
+
+ @Test
+ public void testLoadDefault() {
+ final MetricRegistries r = MetricRegistriesLoader.load();
+ Assert.assertSame(MetricRegistriesImpl.class, r.getClass());
+ }
+
}
diff --git a/ratis-metrics-dropwizard3/pom.xml b/ratis-metrics-dropwizard3/pom.xml
new file mode 100644
index 0000000000..fedabe9dfb
--- /dev/null
+++ b/ratis-metrics-dropwizard3/pom.xml
@@ -0,0 +1,92 @@
+
+
+
+ 4.0.0
+
+ ratis
+ org.apache.ratis
+ 3.0.0-SNAPSHOT
+
+
+ ratis-metrics-dropwizard3
+ Apache Ratis Metrics Dropwizard 3 Implementation
+
+
+ 3.2.5
+
+
+
+
+ ratis-metrics-api
+ org.apache.ratis
+
+
+ ratis-proto
+ org.apache.ratis
+
+
+ ratis-common
+ org.apache.ratis
+
+
+ ratis-common
+ org.apache.ratis
+ test
+ test-jar
+
+
+
+ org.slf4j
+ slf4j-api
+
+
+
+ junit
+ junit
+ test
+
+
+ org.mockito
+ mockito-core
+ test
+
+
+
+ io.dropwizard.metrics
+ metrics-core
+ ${dropwizard3.version}
+
+
+ io.dropwizard.metrics
+ metrics-jvm
+ ${dropwizard3.version}
+ true
+
+
+ io.dropwizard.metrics
+ metrics-ganglia
+ ${dropwizard3.version}
+
+
+ org.acplt
+ oncrpc
+
+
+ true
+
+
+
+
diff --git a/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3JvmMetrics.java b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3JvmMetrics.java
new file mode 100644
index 0000000000..e34c902d56
--- /dev/null
+++ b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3JvmMetrics.java
@@ -0,0 +1,51 @@
+/*
+ * 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.ratis.metrics.dropwizard3;
+
+import org.apache.ratis.metrics.MetricRegistries;
+import org.apache.ratis.metrics.MetricRegistryInfo;
+import org.apache.ratis.metrics.RatisMetricRegistry;
+import org.apache.ratis.util.TimeDuration;
+import com.codahale.metrics.jvm.ClassLoadingGaugeSet;
+import com.codahale.metrics.jvm.GarbageCollectorMetricSet;
+import com.codahale.metrics.jvm.MemoryUsageGaugeSet;
+import com.codahale.metrics.jvm.ThreadStatesGaugeSet;
+
+/**
+ * Helper class to add JVM metrics.
+ */
+public interface Dm3JvmMetrics {
+ static void initJvmMetrics(TimeDuration consoleReportRate) {
+ final MetricRegistries registries = MetricRegistries.global();
+ Dm3JvmMetrics.addJvmMetrics(registries);
+ registries.enableConsoleReporter(consoleReportRate);
+ registries.enableJmxReporter();
+ }
+
+ static void addJvmMetrics(MetricRegistries registries) {
+ MetricRegistryInfo info = new MetricRegistryInfo("jvm", "ratis_jvm", "jvm", "jvm metrics");
+
+ RatisMetricRegistry registry = registries.create(info);
+
+ final Dm3RatisMetricRegistryImpl impl = Dm3RatisMetricRegistryImpl.cast(registry);
+ impl.registerAll("gc", new GarbageCollectorMetricSet());
+ impl.registerAll("memory", new MemoryUsageGaugeSet());
+ impl.registerAll("threads", new ThreadStatesGaugeSet());
+ impl.registerAll("classLoading", new ClassLoadingGaugeSet());
+ }
+}
diff --git a/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3MetricRegistriesImpl.java b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3MetricRegistriesImpl.java
new file mode 100644
index 0000000000..7fe4b8daac
--- /dev/null
+++ b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3MetricRegistriesImpl.java
@@ -0,0 +1,129 @@
+/**
+ * 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.ratis.metrics.dropwizard3;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.function.Consumer;
+
+import org.apache.ratis.metrics.MetricRegistries;
+import org.apache.ratis.metrics.MetricRegistryInfo;
+import org.apache.ratis.metrics.RatisMetricRegistry;
+import org.apache.ratis.util.TimeDuration;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Implementation of MetricRegistries that does ref-counting.
+ */
+public class Dm3MetricRegistriesImpl extends MetricRegistries {
+
+ private static final Logger LOG = LoggerFactory.getLogger(Dm3MetricRegistriesImpl.class);
+
+ private final List> reporterRegistrations = new CopyOnWriteArrayList<>();
+
+ private final List> stopReporters = new CopyOnWriteArrayList<>();
+
+ private final Dm3MetricRegistryFactoryImpl factory;
+
+ private final RefCountingMap registries;
+
+ public Dm3MetricRegistriesImpl() {
+ this(new Dm3MetricRegistryFactoryImpl());
+ }
+
+ Dm3MetricRegistriesImpl(Dm3MetricRegistryFactoryImpl factory) {
+ this.factory = factory;
+ this.registries = new RefCountingMap<>();
+ }
+
+ @Override
+ public RatisMetricRegistry create(MetricRegistryInfo info) {
+ return registries.put(info, () -> {
+ if (reporterRegistrations.isEmpty()) {
+ if (LOG.isDebugEnabled()) {
+ LOG.debug("First MetricRegistry has been created without registering reporters. " +
+ "Hence registering JMX reporter by default.");
+ }
+ enableJmxReporter();
+ }
+ RatisMetricRegistry registry = factory.create(info);
+ reporterRegistrations.forEach(reg -> reg.accept(registry));
+ return registry;
+ });
+ }
+
+ @Override
+ public boolean remove(MetricRegistryInfo key) {
+ RatisMetricRegistry registry = registries.get(key);
+ if (registry != null) {
+ stopReporters.forEach(reg -> reg.accept(registry));
+ }
+
+ return registries.remove(key) == null;
+ }
+
+ @Override
+ public Optional get(MetricRegistryInfo info) {
+ return Optional.ofNullable(registries.get(info));
+ }
+
+ @Override
+ public Collection getMetricRegistries() {
+ return Collections.unmodifiableCollection(registries.values());
+ }
+
+ @Override
+ public void clear() {
+ registries.clear();
+ }
+
+ @Override
+ public Set getMetricRegistryInfos() {
+ return Collections.unmodifiableSet(registries.keySet());
+ }
+
+ @Override
+ public void addReporterRegistration(Consumer reporterRegistration,
+ Consumer stopReporter) {
+ if (registries.size() > 0) {
+ LOG.warn("New reporters are added after registries were created. Some metrics will be missing from the reporter. "
+ + "Please add reporter before adding any new registry.");
+ }
+ this.reporterRegistrations.add(reporterRegistration);
+ this.stopReporters.add(stopReporter);
+ }
+
+ @Override
+ public void enableJmxReporter() {
+ addReporterRegistration(
+ Dm3MetricsReporting.jmxReporter(),
+ Dm3MetricsReporting.stopJmxReporter());
+ }
+
+ @Override
+ public void enableConsoleReporter(TimeDuration consoleReportRate) {
+ addReporterRegistration(
+ Dm3MetricsReporting.consoleReporter(consoleReportRate),
+ Dm3MetricsReporting.stopConsoleReporter());
+ }
+}
diff --git a/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3MetricRegistryFactoryImpl.java b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3MetricRegistryFactoryImpl.java
new file mode 100644
index 0000000000..32497c01f5
--- /dev/null
+++ b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3MetricRegistryFactoryImpl.java
@@ -0,0 +1,28 @@
+/**
+ * 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.ratis.metrics.dropwizard3;
+
+import org.apache.ratis.metrics.MetricRegistryFactory;
+import org.apache.ratis.metrics.MetricRegistryInfo;
+
+public class Dm3MetricRegistryFactoryImpl implements MetricRegistryFactory {
+ @Override
+ public Dm3RatisMetricRegistryImpl create(MetricRegistryInfo info) {
+ return new Dm3RatisMetricRegistryImpl(info);
+ }
+}
diff --git a/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3MetricsReporting.java b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3MetricsReporting.java
new file mode 100644
index 0000000000..d4ffb34e7c
--- /dev/null
+++ b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3MetricsReporting.java
@@ -0,0 +1,81 @@
+/*
+ * 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.ratis.metrics.dropwizard3;
+
+import org.apache.ratis.metrics.RatisMetricRegistry;
+import org.apache.ratis.util.TimeDuration;
+
+import com.codahale.metrics.ConsoleReporter;
+import com.codahale.metrics.ScheduledReporter;
+import com.codahale.metrics.JmxReporter;
+
+import java.util.Optional;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+
+final class Dm3MetricsReporting {
+ private Dm3MetricsReporting() {
+ }
+
+ static Consumer consoleReporter(TimeDuration rate) {
+ return registry -> consoleReporter(rate, registry);
+ }
+
+ private static void consoleReporter(TimeDuration rate, RatisMetricRegistry registry) {
+ final Dm3RatisMetricRegistryImpl impl = Dm3RatisMetricRegistryImpl.cast(registry);
+ final ConsoleReporter reporter = ConsoleReporter.forRegistry(impl.getDropWizardMetricRegistry())
+ .convertRatesTo(TimeUnit.SECONDS)
+ .convertDurationsTo(TimeUnit.MILLISECONDS)
+ .build();
+ reporter.start(rate.getDuration(), rate.getUnit());
+ impl.setConsoleReporter(reporter);
+ }
+
+ static Consumer stopConsoleReporter() {
+ return Dm3MetricsReporting::stopConsoleReporter;
+ }
+
+ private static void stopConsoleReporter(RatisMetricRegistry registry) {
+ final Dm3RatisMetricRegistryImpl impl = Dm3RatisMetricRegistryImpl.cast(registry);
+ Optional.ofNullable(impl.getConsoleReporter()).ifPresent(ScheduledReporter::close);
+ }
+
+ static Consumer jmxReporter() {
+ return Dm3MetricsReporting::jmxReporter;
+ }
+
+ private static void jmxReporter(RatisMetricRegistry registry) {
+ final Dm3RatisMetricRegistryImpl impl = Dm3RatisMetricRegistryImpl.cast(registry);
+ final JmxReporter reporter = JmxReporter.forRegistry(impl.getDropWizardMetricRegistry())
+ .inDomain(registry.getMetricRegistryInfo().getApplicationName())
+ .createsObjectNamesWith(new Dm3RatisObjectNameFactory())
+ .build();
+ reporter.start();
+ impl.setJmxReporter(reporter);
+ }
+
+
+ static Consumer stopJmxReporter() {
+ return Dm3MetricsReporting::stopJmxReporter;
+ }
+
+ private static void stopJmxReporter(RatisMetricRegistry registry) {
+ final Dm3RatisMetricRegistryImpl impl = Dm3RatisMetricRegistryImpl.cast(registry);
+ Optional.ofNullable(impl.getJmxReporter()).ifPresent(JmxReporter::close);
+ }
+}
diff --git a/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3RatisMetricRegistryImpl.java b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3RatisMetricRegistryImpl.java
new file mode 100644
index 0000000000..d8b20d1084
--- /dev/null
+++ b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3RatisMetricRegistryImpl.java
@@ -0,0 +1,157 @@
+/*
+ * 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.ratis.metrics.dropwizard3;
+
+import org.apache.ratis.metrics.LongCounter;
+import org.apache.ratis.metrics.MetricRegistryInfo;
+import org.apache.ratis.metrics.RatisMetricRegistry;
+import org.apache.ratis.metrics.Timekeeper;
+import com.codahale.metrics.ConsoleReporter;
+import com.codahale.metrics.Counter;
+import com.codahale.metrics.Gauge;
+import com.codahale.metrics.Metric;
+import com.codahale.metrics.MetricFilter;
+import com.codahale.metrics.MetricRegistry;
+import com.codahale.metrics.MetricSet;
+import com.codahale.metrics.JmxReporter;
+import org.apache.ratis.thirdparty.com.google.common.annotations.VisibleForTesting;
+
+import java.util.Map;
+import java.util.Objects;
+import java.util.SortedMap;
+import java.util.function.Supplier;
+
+/**
+ * Custom implementation of {@link MetricRegistry}.
+ */
+public class Dm3RatisMetricRegistryImpl implements RatisMetricRegistry {
+ static Dm3RatisMetricRegistryImpl cast(RatisMetricRegistry registry) {
+ if (!(registry instanceof Dm3RatisMetricRegistryImpl)) {
+ throw new IllegalStateException("Unexpected class: " + registry.getClass().getName());
+ }
+ return (Dm3RatisMetricRegistryImpl) registry;
+ }
+
+ private final MetricRegistry metricRegistry = new MetricRegistry();
+
+ private final MetricRegistryInfo info;
+ private final String namePrefix;
+
+ private JmxReporter jmxReporter;
+ private ConsoleReporter consoleReporter;
+
+ public Dm3RatisMetricRegistryImpl(MetricRegistryInfo info) {
+ this.info = Objects.requireNonNull(info, "info == null");
+ this.namePrefix = MetricRegistry.name(info.getApplicationName(), info.getMetricsComponentName(), info.getPrefix());
+ }
+
+ @Override
+ public Timekeeper timer(String name) {
+ return new Dm3TimekeeperImpl(metricRegistry.timer(getMetricName(name)));
+ }
+
+ static LongCounter toLongCounter(Counter c) {
+ return new LongCounter() {
+ @Override
+ public void inc(long n) {
+ c.inc(n);
+ }
+
+ @Override
+ public void dec(long n) {
+ c.dec(n);
+ }
+
+ @Override
+ public long getCount() {
+ return c.getCount();
+ }
+ };
+ }
+
+ @Override
+ public LongCounter counter(String name) {
+ return toLongCounter(metricRegistry.counter(getMetricName(name)));
+ }
+
+ @Override
+ public boolean remove(String name) {
+ return metricRegistry.remove(getMetricName(name));
+ }
+
+ static Gauge toGauge(Supplier supplier) {
+ return supplier::get;
+ }
+
+ @Override
+ public void gauge(String name, Supplier> gaugeSupplier) {
+ metricRegistry.gauge(getMetricName(name), () -> toGauge(gaugeSupplier.get()));
+ }
+
+ public SortedMap getGauges(MetricFilter filter) {
+ return metricRegistry.getGauges(filter);
+ }
+
+ @VisibleForTesting
+ public Metric get(String shortName) {
+ return metricRegistry.getMetrics().get(getMetricName(shortName));
+ }
+
+ private String getMetricName(String shortName) {
+ return MetricRegistry.name(namePrefix, shortName);
+ }
+
+ private T register(String name, T metric) throws IllegalArgumentException {
+ return metricRegistry.register(getMetricName(name), metric);
+ }
+
+
+ public MetricRegistry getDropWizardMetricRegistry() {
+ return metricRegistry;
+ }
+
+ @Override public MetricRegistryInfo getMetricRegistryInfo(){
+ return this.info;
+ }
+
+ void registerAll(String prefix, MetricSet metricSet) {
+ for (Map.Entry entry : metricSet.getMetrics().entrySet()) {
+ if (entry.getValue() instanceof MetricSet) {
+ registerAll(prefix + "." + entry.getKey(), (MetricSet) entry.getValue());
+ } else {
+ register(prefix + "." + entry.getKey(), entry.getValue());
+ }
+ }
+ }
+
+ void setJmxReporter(JmxReporter jmxReporter) {
+ this.jmxReporter = jmxReporter;
+ }
+
+ JmxReporter getJmxReporter() {
+ return this.jmxReporter;
+ }
+
+ void setConsoleReporter(ConsoleReporter consoleReporter) {
+ this.consoleReporter = consoleReporter;
+ }
+
+ ConsoleReporter getConsoleReporter() {
+ return this.consoleReporter;
+ }
+}
diff --git a/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3RatisObjectNameFactory.java b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3RatisObjectNameFactory.java
new file mode 100644
index 0000000000..7f6c21930e
--- /dev/null
+++ b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3RatisObjectNameFactory.java
@@ -0,0 +1,44 @@
+/**
+ * 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.ratis.metrics.dropwizard3;
+
+import com.codahale.metrics.ObjectNameFactory;
+
+import javax.management.MalformedObjectNameException;
+import javax.management.ObjectName;
+
+class Dm3RatisObjectNameFactory implements ObjectNameFactory {
+ @Override
+ public ObjectName createName(String type, String domain, String name) {
+ try {
+ ObjectName objectName = new ObjectName(domain, "name", name);
+ if (objectName.isPattern()) {
+ objectName = new ObjectName(domain, "name", ObjectName.quote(name));
+ }
+ return objectName;
+ } catch (MalformedObjectNameException e) {
+ try {
+ return new ObjectName(domain, "name", ObjectName.quote(name));
+ } catch (MalformedObjectNameException mone) {
+ throw new IllegalArgumentException(
+ "Failed to register " + name + ", type=" + type + ", domain=" + domain, mone);
+ }
+ }
+ }
+}
diff --git a/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3TimekeeperImpl.java b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3TimekeeperImpl.java
new file mode 100644
index 0000000000..8dbcb2944c
--- /dev/null
+++ b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/Dm3TimekeeperImpl.java
@@ -0,0 +1,42 @@
+/*
+ * 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.ratis.metrics.dropwizard3;
+
+import org.apache.ratis.metrics.Timekeeper;
+import com.codahale.metrics.Timer;
+
+/**
+ * The default implementation of {@link Timekeeper} by the shaded {@link Timer}.
+ */
+public class Dm3TimekeeperImpl implements Timekeeper {
+ private final Timer timer;
+
+ Dm3TimekeeperImpl(Timer timer) {
+ this.timer = timer;
+ }
+
+ public Timer getTimer() {
+ return timer;
+ }
+
+ @Override
+ public Context time() {
+ final Timer.Context context = timer.time();
+ return context::stop;
+ }
+}
diff --git a/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/RefCountingMap.java b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/RefCountingMap.java
new file mode 100644
index 0000000000..6c3ad6f8cd
--- /dev/null
+++ b/ratis-metrics-dropwizard3/src/main/java/org/apache/ratis/metrics/dropwizard3/RefCountingMap.java
@@ -0,0 +1,94 @@
+/*
+ * 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.ratis.metrics.dropwizard3;
+
+import java.util.Collection;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Supplier;
+import java.util.stream.Collectors;
+
+/**
+ * A map of K to V, but does ref counting for added and removed values. The values are
+ * not added directly, but instead requested from the given Supplier if ref count == 0. Each put()
+ * call will increment the ref count, and each remove() will decrement it. The values are removed
+ * from the map iff ref count == 0.
+ */
+class RefCountingMap {
+ private static class Payload {
+ private final V value;
+ private final AtomicInteger refCount = new AtomicInteger();
+
+ Payload(V v) {
+ this.value = v;
+ }
+
+ V get() {
+ return value;
+ }
+
+ V increment() {
+ return refCount.incrementAndGet() > 0? value: null;
+ }
+
+ Payload decrement() {
+ return refCount.decrementAndGet() > 0? this: null;
+ }
+ }
+
+ private final ConcurrentMap> map = new ConcurrentHashMap<>();
+
+ V put(K k, Supplier supplier) {
+ return map.compute(k, (k1, old) -> old != null? old: new Payload<>(supplier.get())).increment();
+ }
+
+ static V get(Payload p) {
+ return p == null ? null : p.get();
+ }
+
+ V get(K k) {
+ return get(map.get(k));
+ }
+
+ /**
+ * Decrements the ref count of k, and removes from map if ref count == 0.
+ * @param k the key to remove
+ * @return the value associated with the specified key or null if key is removed from map.
+ */
+ V remove(K k) {
+ return get(map.computeIfPresent(k, (k1, v) -> v.decrement()));
+ }
+
+ void clear() {
+ map.clear();
+ }
+
+ Set keySet() {
+ return map.keySet();
+ }
+
+ Collection values() {
+ return map.values().stream().map(Payload::get).collect(Collectors.toList());
+ }
+
+ int size() {
+ return map.size();
+ }
+}
diff --git a/ratis-metrics-dropwizard3/src/main/resources/META-INF/services/org.apache.ratis.metrics.MetricRegistries b/ratis-metrics-dropwizard3/src/main/resources/META-INF/services/org.apache.ratis.metrics.MetricRegistries
new file mode 100644
index 0000000000..a4c32318c2
--- /dev/null
+++ b/ratis-metrics-dropwizard3/src/main/resources/META-INF/services/org.apache.ratis.metrics.MetricRegistries
@@ -0,0 +1,18 @@
+#
+# 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.
+#
+org.apache.ratis.metrics.dropwizard3.Dm3MetricRegistriesImpl
diff --git a/ratis-metrics-dropwizard3/src/test/java/org/apache/ratis/metrics/dropwizard3/TestLoadDm3MetricRegistries.java b/ratis-metrics-dropwizard3/src/test/java/org/apache/ratis/metrics/dropwizard3/TestLoadDm3MetricRegistries.java
new file mode 100644
index 0000000000..dce4e2b940
--- /dev/null
+++ b/ratis-metrics-dropwizard3/src/test/java/org/apache/ratis/metrics/dropwizard3/TestLoadDm3MetricRegistries.java
@@ -0,0 +1,34 @@
+/*
+ * 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.ratis.metrics.dropwizard3;
+
+import org.apache.ratis.metrics.MetricRegistries;
+import org.apache.ratis.metrics.MetricRegistriesLoader;
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Test class for {@link MetricRegistriesLoader}.
+ */
+public class TestLoadDm3MetricRegistries {
+ @Test
+ public void testLoadDm3() {
+ final MetricRegistries r = MetricRegistriesLoader.load();
+ Assert.assertSame(Dm3MetricRegistriesImpl.class, r.getClass());
+ }
+}
diff --git a/ratis-metrics-dropwizard3/src/test/java/org/apache/ratis/metrics/dropwizard3/TestRefCountingMap.java b/ratis-metrics-dropwizard3/src/test/java/org/apache/ratis/metrics/dropwizard3/TestRefCountingMap.java
new file mode 100644
index 0000000000..1aa15d37c7
--- /dev/null
+++ b/ratis-metrics-dropwizard3/src/test/java/org/apache/ratis/metrics/dropwizard3/TestRefCountingMap.java
@@ -0,0 +1,147 @@
+/*
+ * 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.ratis.metrics.dropwizard3;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Collection;
+import java.util.Set;
+
+import org.apache.ratis.thirdparty.com.google.common.collect.Lists;
+import org.junit.Before;
+import org.junit.Test;
+
+public class TestRefCountingMap {
+
+ private RefCountingMap map;
+
+ @Before
+ public void setUp() {
+ map = new RefCountingMap<>();
+ }
+
+ @Test
+ public void testPutGet() {
+ map.put("foo", () -> "foovalue");
+
+ String v = map.get("foo");
+ assertNotNull(v);
+ assertEquals("foovalue", v);
+ }
+
+ @Test
+ public void testPutMulti() {
+ String v1 = map.put("foo", () -> "foovalue");
+ String v2 = map.put("foo", () -> "foovalue2");
+ String v3 = map.put("foo", () -> "foovalue3");
+
+ String v = map.get("foo");
+ assertEquals("foovalue", v);
+ assertEquals(v, v1);
+ assertEquals(v, v2);
+ assertEquals(v, v3);
+ }
+
+ @Test
+ public void testPutRemove() {
+ map.put("foo", () -> "foovalue");
+ String v = map.remove("foo");
+ assertNull(v);
+ v = map.get("foo");
+ assertNull(v);
+ }
+
+ @Test
+ public void testPutRemoveMulti() {
+ map.put("foo", () -> "foovalue");
+ map.put("foo", () -> "foovalue2");
+ map.put("foo", () -> "foovalue3");
+
+ // remove 1
+ String v = map.remove("foo");
+ assertEquals("foovalue", v);
+
+ // remove 2
+ v = map.remove("foo");
+ assertEquals("foovalue", v);
+
+ // remove 3
+ v = map.remove("foo");
+ assertNull(v);
+ v = map.get("foo");
+ assertNull(v);
+ }
+
+ @Test
+ public void testSize() {
+ assertEquals(0, map.size());
+
+ // put a key
+ map.put("foo", () -> "foovalue");
+ assertEquals(1, map.size());
+
+ // put a different key
+ map.put("bar", () -> "foovalue2");
+ assertEquals(2, map.size());
+
+ // put the same key again
+ map.put("bar", () -> "foovalue3");
+ assertEquals(2, map.size()); // map should be same size
+ }
+
+ @Test
+ public void testClear() {
+ map.put("foo", () -> "foovalue");
+ map.put("bar", () -> "foovalue2");
+ map.put("baz", () -> "foovalue3");
+
+ map.clear();
+
+ assertEquals(0, map.size());
+ }
+
+
+ @Test
+ public void testKeySet() {
+ map.put("foo", () -> "foovalue");
+ map.put("bar", () -> "foovalue2");
+ map.put("baz", () -> "foovalue3");
+
+ Set keys = map.keySet();
+ assertEquals(3, keys.size());
+
+ Lists.newArrayList("foo", "bar", "baz").stream().forEach(v -> assertTrue(keys.contains(v)));
+ }
+
+ @Test
+ public void testValues() {
+ map.put("foo", () -> "foovalue");
+ map.put("foo", () -> "foovalue2");
+ map.put("bar", () -> "foovalue3");
+ map.put("baz", () -> "foovalue4");
+
+ Collection values = map.values();
+ assertEquals(3, values.size());
+
+ Lists.newArrayList("foovalue", "foovalue3", "foovalue4").stream()
+ .forEach(v -> assertTrue(values.contains(v)));
+ }
+}