Github user zentol commented on a diff in the pull request:
https://github.com/apache/flink/pull/3833#discussion_r116368588
--- Diff:
flink-metrics/flink-metrics-prometheus/src/main/java/org/apache/flink/metrics/prometheus/PrometheusReporter.java
---
@@ -0,0 +1,256 @@
+/*
+ * 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.metrics.prometheus;
+
+import com.google.common.base.CharMatcher;
+import com.google.common.collect.ImmutableList;
+import fi.iki.elonen.NanoHTTPD;
+import io.prometheus.client.Collector;
+import io.prometheus.client.CollectorRegistry;
+import io.prometheus.client.exporter.common.TextFormat;
+import org.apache.flink.annotation.PublicEvolving;
+import org.apache.flink.annotation.VisibleForTesting;
+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.Meter;
+import org.apache.flink.metrics.Metric;
+import org.apache.flink.metrics.MetricConfig;
+import org.apache.flink.metrics.MetricGroup;
+import org.apache.flink.metrics.reporter.MetricReporter;
+import org.apache.flink.runtime.metrics.groups.AbstractMetricGroup;
+import org.apache.flink.runtime.metrics.groups.FrontMetricGroup;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.io.StringWriter;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.regex.Pattern;
+
+import static com.google.common.collect.Iterables.toArray;
+
+@PublicEvolving
+public class PrometheusReporter implements MetricReporter {
+ private static final Logger log =
LoggerFactory.getLogger(PrometheusReporter.class);
+
+ static final String ARG_PORT = "port";
+ private static final int DEFAULT_PORT = 9249;
+
+ private static final Pattern UNALLOWED_CHAR_PATTERN =
Pattern.compile("[^a-zA-Z0-9:_]");
+ private static final CharacterFilter CHARACTER_FILTER = new
CharacterFilter() {
+ @Override
+ public String filterCharacters(String input) {
+ return replaceInvalidChars(input);
+ }
+ };
+
+ private static final char SCOPE_SEPARATOR = '_';
+
+ private PrometheusEndpoint prometheusEndpoint;
+ private Map<String, Collector> collectorsByMetricName = new HashMap<>();
+
+ @VisibleForTesting
+ static String replaceInvalidChars(final String input) {
+ // https://prometheus.io/docs/instrumenting/writing_exporters/
+ // Only [a-zA-Z0-9:_] are valid in metric names, any other
characters should be sanitized to an underscore.
+ return UNALLOWED_CHAR_PATTERN.matcher(input).replaceAll("_");
+ }
+
+ @Override
+ public void open(MetricConfig config) {
+ int port = config.getInteger(ARG_PORT, DEFAULT_PORT);
+ log.info("Using port {}.", port);
+ prometheusEndpoint = new PrometheusEndpoint(port);
+ try {
+ prometheusEndpoint.start(NanoHTTPD.SOCKET_READ_TIMEOUT,
true);
+ } catch (IOException e) {
+ log.error("Could not start PrometheusEndpoint on port "
+ port, e);
+ }
+ }
+
+ @Override
+ public void close() {
+ prometheusEndpoint.stop();
+ CollectorRegistry.defaultRegistry.clear();
+ }
+
+ @Override
+ public void notifyOfAddedMetric(final Metric metric, final String
metricName, final MetricGroup group) {
+ final String scope =
((FrontMetricGroup<AbstractMetricGroup<?>>)
group).getLogicalScope(CHARACTER_FILTER, SCOPE_SEPARATOR);
+ List<String> dimensionKeys = new LinkedList<>();
+ List<String> dimensionValues = new LinkedList<>();
+ for (final Map.Entry<String, String> dimension :
group.getAllVariables().entrySet()) {
+
dimensionKeys.add(CHARACTER_FILTER.filterCharacters(CharMatcher.anyOf("<>").trimFrom(dimension.getKey())));
+
dimensionValues.add(CHARACTER_FILTER.filterCharacters(dimension.getValue()));
+ }
+
+ final String validMetricName = scope + SCOPE_SEPARATOR +
CHARACTER_FILTER.filterCharacters(metricName);
+ final String metricIdentifier =
group.getMetricIdentifier(metricName);
+ final Collector collector;
+ if (metric instanceof Gauge) {
+ collector = createGauge((Gauge) metric,
validMetricName, metricIdentifier, dimensionKeys, dimensionValues);
+ } else if (metric instanceof Counter) {
+ collector = createGauge((Counter) metric,
validMetricName, metricIdentifier, dimensionKeys, dimensionValues);
+ } else if (metric instanceof Histogram) {
+ collector = createSummary((Histogram) metric,
validMetricName, metricIdentifier, dimensionKeys, dimensionValues);
+ } else if (metric instanceof Meter) {
+ collector = createCounter((Meter) metric,
validMetricName, metricIdentifier, dimensionKeys, dimensionValues);
+ } else {
+ log.error("Cannot add unknown metric type: {}. This
indicates that the metric type is not supported by this reporter.",
--- End diff --
By convention classes that are part of the metric system never log
something as errors but only warnings, the reason being that errors are
something that interfere with the job being executed.
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