org.apache.pulsar.functions.instance.stats.PrometheusTextFormat Maven / Gradle / Ivy
/*
* 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.pulsar.functions.instance.stats;
import io.prometheus.client.Collector;
import java.io.IOException;
import java.io.Writer;
import java.util.Enumeration;
/**
* Provide Prometheus text format for a collection of metrics, without the HELP string.
*/
public class PrometheusTextFormat {
/**
* Write out the text version 0.0.4 of the given MetricFamilySamples.
*/
public static void write004(Writer writer, Enumeration mfs) throws IOException {
/*
* See http://prometheus.io/docs/instrumenting/exposition_formats/ for the output format specification.
*/
while (mfs.hasMoreElements()) {
Collector.MetricFamilySamples metricFamilySamples = mfs.nextElement();
writer.write("# TYPE ");
writer.write(metricFamilySamples.name);
writer.write(' ');
writer.write(metricFamilySamples.type.name().toLowerCase());
writer.write('\n');
for (Collector.MetricFamilySamples.Sample sample : metricFamilySamples.samples) {
writer.write(sample.name);
if (sample.labelNames.size() > 0) {
writer.write('{');
for (int i = 0; i < sample.labelNames.size(); ++i) {
writer.write(sample.labelNames.get(i));
writer.write("=\"");
writeEscapedLabelValue(writer, sample.labelValues.get(i));
writer.write("\",");
}
writer.write('}');
}
writer.write(' ');
writer.write(Collector.doubleToGoString(sample.value));
if (sample.timestampMs != null) {
writer.write(' ');
writer.write(sample.timestampMs.toString());
}
writer.write('\n');
}
}
}
private static void writeEscapedLabelValue(Writer writer, String s) throws IOException {
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
switch (c) {
case '\\':
writer.append("\\\\");
break;
case '\"':
writer.append("\\\"");
break;
case '\n':
writer.append("\\n");
break;
default:
writer.append(c);
}
}
}
}