Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/2363#discussion_r75450989
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/metrics/MetricQueryService.java
---
@@ -0,0 +1,180 @@
+/*
+ * 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.flink.runtime.metrics;
+
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+import akka.actor.UntypedActor;
+import org.apache.flink.api.java.tuple.Tuple3;
+import org.apache.flink.metrics.CharacterFilter;
+import org.apache.flink.metrics.Counter;
+import org.apache.flink.metrics.Gauge;
+import org.apache.flink.metrics.Histogram;
+import org.apache.flink.metrics.HistogramStatistics;
+import org.apache.flink.metrics.Metric;
+import org.apache.flink.runtime.metrics.groups.AbstractMetricGroup;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * The MetricQueryService creates a key-value representation of all
metrics currently registered with Flink when queried.
+ *
+ * It is realized as an actor and receives the following messages:
+ * - {@code Tuple3<String, Metric, AbstractMetricGroup> => Notification of
added Metric}
+ * - {@code Metric => Notification of removed Metric}
+ * - {@code ActorRef => Query for metric dump}
+ */
+public class MetricQueryService extends UntypedActor {
+ private static final Logger LOG =
LoggerFactory.getLogger(MetricQueryService.class);
+
+ public static final byte CATEGORY_COUNTER = 0;
+ public static final byte CATEGORY_GAUGE = 1;
+ public static final byte CATEGORY_HISTOGRAM = 2;
+
+ private final Map<Gauge<?>, String> gauges = new HashMap<>();
+ private final Map<Counter, String> counters = new HashMap<>();
+ private final Map<Histogram, String> histograms = new HashMap<>();
+
+ private final List<Metric> toRemove = new ArrayList<>();
+
+ @Override
+ public void onReceive(Object message) throws Exception {
+ try {
+ if (message instanceof Tuple3) { // add metric
+ Tuple3<String, Metric, AbstractMetricGroup>
tuple = (Tuple3<String, Metric, AbstractMetricGroup>) message;
+
+ String metricName = tuple.f0;
+ Metric metric = tuple.f1;
+ AbstractMetricGroup group = tuple.f2;
+
+ String name =
group.getQueryServiceMetricIdentifier(metricName, new CharacterFilter() {
+ @Override
+ public String filterCharacters(String
input) {
+ return input.replaceAll("[
:.,]", "_");
+ }
+ });
+
+ if (metric instanceof Counter) {
+ counters.put((Counter) metric, name);
+ } else if (metric instanceof Gauge) {
+ gauges.put((Gauge<?>) metric, name);
+ } else if (metric instanceof Histogram) {
+ histograms.put((Histogram) metric,
name);
+ }
+ } else if (message instanceof Metric) { // remove metric
+ toRemove.add((Metric) message);
+ } else if (message instanceof ActorRef) { // create dump
+ Object[] dump = createDump();
+ ((ActorRef) message).tell(dump, getSelf());
+ removeMetrics();
+ } else {
+ LOG.warn("MetricQueryServiceActor received an
invalid message. " + message.toString());
+ }
+ } catch (Exception e) {
+ LOG.warn("An exception occurred while processing a
message.", e);
+ }
+ }
+
+ private Object[] createDump() {
+ Object[] metrics = new Object[(this.counters.size() +
this.gauges.size()) * 3 + this.histograms.size() * 13];
+
+ int index = 0;
+
+ // dump counters
+ for (Map.Entry<Counter, String> counter :
this.counters.entrySet()) {
+ metrics[index++] = CATEGORY_COUNTER;
+ metrics[index++] = counter.getValue();
+ metrics[index++] = counter.getKey().getCount();
+ }
+ // dump gauges
+ for (Map.Entry<Gauge<?>, String> gauge :
this.gauges.entrySet()) {
+ metrics[index++] = CATEGORY_GAUGE;
+ metrics[index++] = gauge.getValue();
+ metrics[index++] = gauge.getKey().getValue().toString();
+ }
+ // dump histograms
+ for (Map.Entry<Histogram, String> histogram :
this.histograms.entrySet()) {
+ HistogramStatistics stat =
histogram.getKey().getStatistics();
+
+ metrics[index++] = CATEGORY_HISTOGRAM;
+ metrics[index++] = histogram.getValue();
+ metrics[index++] = stat.getMin();
+ metrics[index++] = stat.getMax();
+ metrics[index++] = stat.getMean();
+ metrics[index++] = stat.getQuantile(0.5);
+ metrics[index++] = stat.getStdDev();
+ metrics[index++] = stat.getQuantile(0.75);
+ metrics[index++] = stat.getQuantile(0.9);
+ metrics[index++] = stat.getQuantile(0.95);
+ metrics[index++] = stat.getQuantile(0.98);
+ metrics[index++] = stat.getQuantile(0.99);
+ metrics[index++] = stat.getQuantile(0.999);
+ }
+ return metrics;
+ }
+
+ private void removeMetrics() {
+ for (Metric metric : toRemove) {
+ if (metric instanceof Counter) {
+ this.counters.remove(metric);
+ } else if (metric instanceof Gauge) {
+ this.gauges.remove(metric);
+ } else if (metric instanceof Histogram) {
+ this.histograms.remove(metric);
+ }
+ }
+ }
+
+ /**
+ * Starts the MetricQueryService actor in the given actor system.
+ *
+ * @param actorSystem The actor system running the MetricQueryService
+ * @return actor reference to the MetricQueryService
+ */
+ public static ActorRef startMetricQueryService(ActorSystem actorSystem)
{
+ return
actorSystem.actorOf(Props.create(MetricQueryService.class));
--- End diff --
`actorSystem.actorOf(Props.create(MetricQueryService.class), "foobar")`
creates an actor with the name "foobar". If your actor system is the Flink
actor system, then it should be reachable via
`akka.tcp://fl...@xxx.yyy.zzz:port/foobar` if I'm not mistaken. But you would
need an actorsystem reference in the web server to do the actor resolution.
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