| /** |
| * 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.hadoop.hdds.server.http; |
| |
| import javax.servlet.ServletException; |
| import javax.servlet.http.HttpServlet; |
| import javax.servlet.http.HttpServletRequest; |
| import javax.servlet.http.HttpServletResponse; |
| import java.io.IOException; |
| import java.io.PrintWriter; |
| |
| import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem; |
| |
| import io.prometheus.client.CollectorRegistry; |
| import io.prometheus.client.exporter.common.TextFormat; |
| |
| /** |
| * Servlet to publish hadoop metrics in prometheus format. |
| */ |
| public class PrometheusServlet extends HttpServlet { |
| |
| public static final String SECURITY_TOKEN = "PROMETHEUS_SECURITY_TOKEN"; |
| public static final String BEARER = "Bearer"; |
| |
| public PrometheusMetricsSink getPrometheusSink() { |
| return |
| (PrometheusMetricsSink) getServletContext().getAttribute( |
| BaseHttpServer.PROMETHEUS_SINK); |
| } |
| |
| @Override |
| protected void doGet(HttpServletRequest req, HttpServletResponse resp) |
| throws ServletException, IOException { |
| String securityToken = |
| (String) getServletContext().getAttribute(SECURITY_TOKEN); |
| if (securityToken != null) { |
| String authorizationHeader = req.getHeader("Authorization"); |
| if (authorizationHeader == null |
| || !authorizationHeader.startsWith(BEARER) |
| || !securityToken.equals( |
| authorizationHeader.substring(BEARER.length() + 1))) { |
| resp.setStatus(HttpServletResponse.SC_FORBIDDEN); |
| return; |
| } |
| } |
| DefaultMetricsSystem.instance().publishMetricsNow(); |
| PrintWriter writer = resp.getWriter(); |
| getPrometheusSink().writeMetrics(writer); |
| writer.write("\n\n#Dropwizard metrics\n\n"); |
| //print out dropwizard metrics used by ratis. |
| TextFormat.write004(writer, |
| CollectorRegistry.defaultRegistry.metricFamilySamples()); |
| writer.flush(); |
| } |
| } |