TaggedMetricRegistry composability

tritium-registry/build.gradle

@@ -4,6 +4,7 @@ dependencies {
     processor 'com.google.auto.service:auto-service'
     processor 'org.immutables:value'
 
+    compile 'com.google.guava:guava'
     compile 'com.palantir.safe-logging:safe-logging'
     compile 'io.dropwizard.metrics:metrics-core'
 

tritium-registry/src/main/java/com/palantir/tritium/metrics/registry/DefaultTaggedMetricRegistry.java

@@ -24,7 +24,8 @@
 import com.codahale.metrics.Metric;
 import com.codahale.metrics.Timer;
 import com.google.auto.service.AutoService;
-import java.util.Collections;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Maps;
 import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.ConcurrentHashMap;
@@ -36,6 +37,7 @@ public final class DefaultTaggedMetricRegistry implements TaggedMetricRegistry {
     private static final TaggedMetricRegistry DEFAULT = new DefaultTaggedMetricRegistry();
 
     private final Map<MetricName, Metric> registry = new ConcurrentHashMap<>();
+    private final Map<Map.Entry<String, String>, TaggedMetricSet> taggedRegistries = new ConcurrentHashMap<>();
 
     public DefaultTaggedMetricRegistry() {}
 
@@ -93,14 +95,34 @@ public Timer timer(MetricName metricName, Supplier<Timer> timerSupplier) {
 
     @Override
     public Map<MetricName, Metric> getMetrics() {
-        return Collections.unmodifiableMap(registry);
+        ImmutableMap.Builder<MetricName, Metric> result = ImmutableMap.<MetricName, Metric>builder()
+                .putAll(registry);
+        taggedRegistries.forEach((tag, metrics) -> metrics.getMetrics()
+                .forEach((metricName, metric) -> result.put(
+                        MetricName.builder()
+                                .from(metricName)
+                                .putSafeTags(tag.getKey(), tag.getValue())
+                                .build(),
+                        metric)));
+
+        return result.build();
     }
 
     @Override
     public Optional<Metric> remove(MetricName metricName) {
         return Optional.ofNullable(registry.remove(metricName));
     }
 
+    @Override
+    public void addMetrics(String safeTagName, String safeTagValue, TaggedMetricSet other) {
+        taggedRegistries.put(Maps.immutableEntry(safeTagName, safeTagValue), other);
+    }
+
+    @Override
+    public Optional<TaggedMetricSet> removeMetrics(String safeTagName, String safeTagValue) {
+        return Optional.ofNullable(taggedRegistries.remove(Maps.immutableEntry(safeTagName, safeTagValue)));
+    }
+
     private <T extends Metric> T getOrAdd(MetricName metricName, Class<T> metricClass, Supplier<T> metricSupplier) {
         Metric metric = registry.computeIfAbsent(metricName, name -> metricSupplier.get());
         if (!metricClass.isInstance(metric)) {

tritium-registry/src/main/java/com/palantir/tritium/metrics/registry/DropwizardTaggedMetricSet.java

@@ -0,0 +1,37 @@
+/*
+ * (c) Copyright 2018 Palantir Technologies Inc. All rights reserved.
+ *
+ * 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 com.palantir.tritium.metrics.registry;
+
+import static java.util.stream.Collectors.toMap;
+
+import com.codahale.metrics.Metric;
+import com.codahale.metrics.MetricSet;
+import java.util.Map;
+
+public final class DropwizardTaggedMetricSet implements TaggedMetricSet {
+    private final MetricSet metricSet;
+
+    public DropwizardTaggedMetricSet(MetricSet metricSet) {
+        this.metricSet = metricSet;
+    }
+
+    @Override
+    public Map<MetricName, Metric> getMetrics() {
+        return metricSet.getMetrics().entrySet().stream()
+                .collect(toMap(entry -> MetricName.builder().safeName(entry.getKey()).build(), Map.Entry::getValue));
+    }
+}

tritium-registry/src/main/java/com/palantir/tritium/metrics/registry/TaggedMetricRegistry.java

@@ -22,14 +22,13 @@
 import com.codahale.metrics.Meter;
 import com.codahale.metrics.Metric;
 import com.codahale.metrics.Timer;
-import java.util.Map;
 import java.util.Optional;
 import java.util.function.Supplier;
 
 /**
  * Similar to {@link com.codahale.metrics.MetricRegistry} but allows tagging of {@link Metric}s.
  */
-public interface TaggedMetricRegistry {
+public interface TaggedMetricRegistry extends TaggedMetricSet {
 
     /**
      * Returns existing or new timer metric for the specified metric name.
@@ -81,13 +80,6 @@ public interface TaggedMetricRegistry {
 
     Counter counter(MetricName metricName, Supplier<Counter> counterSupplier);
 
-    /**
-     * Returns a map of registered metrics.
-     *
-     * @return map of registered metrics
-     */
-    Map<MetricName, Metric> getMetrics();
-
     /**
      * Removes the tagged metric with the specified metric name.
      *
@@ -96,4 +88,24 @@ public interface TaggedMetricRegistry {
      */
     Optional<Metric> remove(MetricName metricName);
 
+    /**
+     * Adds a set of metrics to this TaggedMetricRegistry's metric set,
+     * which are to be uniquely identified by the tags provided.
+     * <p>
+     * So, if I have a metric registry with a single metric called 'foo', and I add it
+     * with tag (bar, baz), this registry will now contain 'foo', tagged with (bar, baz).
+     * <p>
+     * If a metric exists with duplicate tags, then calling {@link TaggedMetricSet#getMetrics}
+     * will be impossible.
+     *
+     * @param safeTagName a tag key which should be added to all metrics in the metrics set
+     * @param safeTagValue a tag value which should be added to all metrics in the metrics set
+     * @param metrics the metrics which should be added
+     */
+    void addMetrics(String safeTagName, String safeTagValue, TaggedMetricSet metrics);
+
+    /**
+     * Removes a TaggedMetricsSet added via addMetrics from this metrics set.
+     */
+    Optional<TaggedMetricSet> removeMetrics(String safeTagName, String safeTagValue);
 }

tritium-registry/src/main/java/com/palantir/tritium/metrics/registry/TaggedMetricSet.java

@@ -0,0 +1,29 @@
+/*
+ * (c) Copyright 2018 Palantir Technologies Inc. All rights reserved.
+ *
+ * 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 com.palantir.tritium.metrics.registry;
+
+import com.codahale.metrics.Metric;
+import java.util.Map;
+
+public interface TaggedMetricSet {
+    /**
+     * Returns a map of metrics.
+     *
+     * @return map of metrics
+     */
+    Map<MetricName, Metric> getMetrics();
+}

tritium-registry/src/test/java/com/palantir/tritium/metrics/registry/TaggedMetricRegistryTest.java

@@ -153,4 +153,18 @@ public void testRemoveMetric() {
 
         assertThat(registry.remove(METRIC_1).isPresent()).isFalse();
     }
+
+    @Test
+    public void testAddMetricRegistry() {
+        String name = "name";
+        String tagKey = "tagKey";
+        String tagValue = "tagValue";
+        TaggedMetricRegistry child = new DefaultTaggedMetricRegistry();
+        Meter meter = child.meter(MetricName.builder().safeName(name).build());
+        registry.addMetrics(tagKey, tagValue, child);
+        assertThat(registry.getMetrics())
+                .containsEntry(MetricName.builder().safeName(name).putSafeTags(tagKey, tagValue).build(), meter);
+        registry.removeMetrics(tagKey, tagValue);
+        assertThat(registry.getMetrics()).isEmpty();
+    }
 }