Java tutorial
/** * Copyright 2015-2016 The OpenZipkin Authors * * 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 zipkin.autoconfigure.metrics; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.actuate.endpoint.PublicMetrics; import org.springframework.boot.actuate.metrics.Metric; import org.springframework.http.MediaType; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RestController; import java.util.Collection; import java.util.regex.Pattern; @RestController @RequestMapping("/prometheus") public class PrometheusMetricsAutoConfiguration { private static final Pattern SANITIZE_PREFIX_PATTERN = Pattern.compile("^[^a-zA-Z_]"); private static final Pattern SANITIZE_BODY_PATTERN = Pattern.compile("[^a-zA-Z0-9_]"); private final Collection<PublicMetrics> publicMetrics; @Autowired public PrometheusMetricsAutoConfiguration(Collection<PublicMetrics> publicMetrics) { this.publicMetrics = publicMetrics; } private static String sanitizeMetricName(String metricName) { return SANITIZE_BODY_PATTERN.matcher(SANITIZE_PREFIX_PATTERN.matcher(metricName).replaceFirst("_")) .replaceAll("_"); } @RequestMapping(method = RequestMethod.GET) public ResponseEntity<String> prometheusMetrics() { StringBuilder sb = new StringBuilder(); for (PublicMetrics publicMetrics : this.publicMetrics) { for (Metric<?> metric : publicMetrics.metrics()) { final String sanitizedName = sanitizeMetricName(metric.getName()); final String type = typeForName(sanitizedName); final String metricName = metricName(sanitizedName, type); double value = metric.getValue().doubleValue(); sb.append(String.format("#TYPE %s %s\n", metricName, type)); sb.append(String.format("#HELP %s %s\n", metricName, metricName)); sb.append(String.format("%s %s\n", metricName, prometheusDouble(value))); } } return ResponseEntity.ok().contentType(MediaType.parseMediaType("text/plain; version=0.0.4; charset=utf-8")) .body(sb.toString()); } private String prometheusDouble(double value) { if (value == Double.POSITIVE_INFINITY) { return "+Inf"; } else if (value == Double.NEGATIVE_INFINITY) { return "-Inf"; } else { return String.valueOf(value); } } private String metricName(String name, String type) { switch (type) { case "counter": return name.replaceFirst("^counter_", ""); case "gauge": return name.replaceFirst("^gauge_", ""); default: return name; } } private String typeForName(String name) { if (name.startsWith("gauge")) { return "gauge"; } if (name.startsWith("counter")) { return "counter"; } return "gauge"; } }