| /** |
| * 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.metrics; |
| |
| import java.io.IOException; |
| import java.io.PrintWriter; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.TreeMap; |
| |
| import javax.servlet.ServletException; |
| import javax.servlet.http.HttpServlet; |
| import javax.servlet.http.HttpServletRequest; |
| import javax.servlet.http.HttpServletResponse; |
| |
| import org.apache.hadoop.metrics.spi.OutputRecord; |
| import org.apache.hadoop.metrics.spi.AbstractMetricsContext.MetricMap; |
| import org.apache.hadoop.metrics.spi.AbstractMetricsContext.TagMap; |
| import org.mortbay.util.ajax.JSON; |
| import org.mortbay.util.ajax.JSON.Output; |
| |
| /** |
| * A servlet to print out metrics data. By default, the servlet returns a |
| * textual representation (no promises are made for parseability), and |
| * users can use "?format=json" for parseable output. |
| */ |
| public class MetricsServlet extends HttpServlet { |
| |
| /** |
| * A helper class to hold a TagMap and MetricMap. |
| */ |
| static class TagsMetricsPair implements JSON.Convertible { |
| final TagMap tagMap; |
| final MetricMap metricMap; |
| |
| public TagsMetricsPair(TagMap tagMap, MetricMap metricMap) { |
| this.tagMap = tagMap; |
| this.metricMap = metricMap; |
| } |
| |
| @SuppressWarnings("unchecked") |
| public void fromJSON(Map map) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** Converts to JSON by providing an array. */ |
| public void toJSON(Output out) { |
| out.add(new Object[] { tagMap, metricMap }); |
| } |
| } |
| |
| /** |
| * Collects all metric data, and returns a map: |
| * contextName -> recordName -> [ (tag->tagValue), (metric->metricValue) ]. |
| * The values are either String or Number. The final value is implemented |
| * as a list of TagsMetricsPair. |
| */ |
| Map<String, Map<String, List<TagsMetricsPair>>> makeMap( |
| Collection<MetricsContext> contexts) throws IOException { |
| Map<String, Map<String, List<TagsMetricsPair>>> map = |
| new TreeMap<String, Map<String, List<TagsMetricsPair>>>(); |
| |
| for (MetricsContext context : contexts) { |
| Map<String, List<TagsMetricsPair>> records = |
| new TreeMap<String, List<TagsMetricsPair>>(); |
| map.put(context.getContextName(), records); |
| |
| for (Map.Entry<String, Collection<OutputRecord>> r : |
| context.getAllRecords().entrySet()) { |
| List<TagsMetricsPair> metricsAndTags = |
| new ArrayList<TagsMetricsPair>(); |
| records.put(r.getKey(), metricsAndTags); |
| for (OutputRecord outputRecord : r.getValue()) { |
| TagMap tagMap = outputRecord.getTagsCopy(); |
| MetricMap metricMap = outputRecord.getMetricsCopy(); |
| metricsAndTags.add(new TagsMetricsPair(tagMap, metricMap)); |
| } |
| } |
| } |
| return map; |
| } |
| |
| @Override |
| public void doGet(HttpServletRequest request, HttpServletResponse response) |
| throws ServletException, IOException { |
| PrintWriter out = new PrintWriter(response.getOutputStream()); |
| String format = request.getParameter("format"); |
| Collection<MetricsContext> allContexts = |
| ContextFactory.getFactory().getAllContexts(); |
| if ("json".equals(format)) { |
| // Uses Jetty's built-in JSON support to convert the map into JSON. |
| out.print(new JSON().toJSON(makeMap(allContexts))); |
| } else { |
| printMap(out, makeMap(allContexts)); |
| } |
| out.close(); |
| } |
| |
| /** |
| * Prints metrics data in a multi-line text form. |
| */ |
| void printMap(PrintWriter out, Map<String, Map<String, List<TagsMetricsPair>>> map) { |
| for (Map.Entry<String, Map<String, List<TagsMetricsPair>>> context : map.entrySet()) { |
| out.println(context.getKey()); |
| for (Map.Entry<String, List<TagsMetricsPair>> record : context.getValue().entrySet()) { |
| indent(out, 1); |
| out.println(record.getKey()); |
| for (TagsMetricsPair pair : record.getValue()) { |
| indent(out, 2); |
| // Prints tag values in the form "{key=value,key=value}:" |
| out.print("{"); |
| boolean first = true; |
| for (Map.Entry<String, Object> tagValue : pair.tagMap.entrySet()) { |
| if (first) { |
| first = false; |
| } else { |
| out.print(","); |
| } |
| out.print(tagValue.getKey()); |
| out.print("="); |
| out.print(tagValue.getValue().toString()); |
| } |
| out.println("}:"); |
| |
| // Now print metric values, one per line |
| for (Map.Entry<String, Number> metricValue : |
| pair.metricMap.entrySet()) { |
| indent(out, 3); |
| out.print(metricValue.getKey()); |
| out.print("="); |
| out.println(metricValue.getValue().toString()); |
| } |
| } |
| } |
| } |
| } |
| |
| private void indent(PrintWriter out, int indent) { |
| for (int i = 0; i < indent; ++i) { |
| out.append(" "); |
| } |
| } |
| } |