001/*
002 * (C) Copyright 2017 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     bdelbosc
018 */
019package org.nuxeo.lib.stream.tools.command;
020
021import java.time.Duration;
022
023import org.apache.commons.cli.CommandLine;
024import org.apache.commons.cli.Option;
025import org.apache.commons.cli.Options;
026import org.apache.commons.logging.Log;
027import org.apache.commons.logging.LogFactory;
028import org.nuxeo.lib.stream.computation.Record;
029import org.nuxeo.lib.stream.log.LogManager;
030import org.nuxeo.lib.stream.log.LogRecord;
031import org.nuxeo.lib.stream.log.LogTailer;
032import org.nuxeo.lib.stream.tools.renderer.Renderer;
033
034/**
035 * Output the last records on a Log.
036 *
037 * @since 9.3
038 */
039public class TailCommand extends Command {
040    private static final Log log = LogFactory.getLog(TailCommand.class);
041
042    protected static final String NAME = "tail";
043
044    @Override
045    public String name() {
046        return NAME;
047    }
048
049    @Override
050    public void updateOptions(Options options) {
051        options.addOption(Option.builder("n")
052                                .longOpt("lines")
053                                .desc("output the last NUM records")
054                                .hasArg()
055                                .argName("NUM")
056                                .build());
057        options.addOption("f", "follow", false, "output appended records");
058        options.addOption(Option.builder("l")
059                                .longOpt("log-name")
060                                .desc("Log name")
061                                .required()
062                                .hasArg()
063                                .argName("LOG_NAME")
064                                .build());
065        options.addOption(
066                Option.builder("g").longOpt("group").desc("Consumer group").hasArg().argName("GROUP").build());
067        options.addOption(Option.builder()
068                                .longOpt("codec")
069                                .desc("Codec used to read record, can be: java, avro, avroBinary, avroJson")
070                                .hasArg()
071                                .argName("CODEC")
072                                .build());
073        options.addOption(
074                Option.builder().longOpt("render").desc("Output rendering").hasArg().argName("FORMAT").build());
075        options.addOption(Option.builder("t")
076                                .longOpt("timeout")
077                                .desc("Timeout on follow in second")
078                                .hasArg()
079                                .argName("TIMEOUT")
080                                .build());
081    }
082
083    @Override
084    public boolean run(LogManager manager, CommandLine cmd) throws InterruptedException {
085        int lines = Integer.parseInt(cmd.getOptionValue("lines", "10"));
086        String name = cmd.getOptionValue("log-name");
087        String render = cmd.getOptionValue("render", "default");
088        String group = cmd.getOptionValue("group", "tools");
089        String codec = cmd.getOptionValue("codec");
090        int timeout = Integer.parseInt(cmd.getOptionValue("timeout", "120"));
091        tail(manager, name, group, lines, getRecordRenderer(render), codec);
092        if (cmd.hasOption("follow")) {
093            follow(manager, name, group, getRecordRenderer(render), timeout, codec);
094        }
095        return true;
096    }
097
098    @SuppressWarnings("unchecked")
099    protected void tail(LogManager manager, String name, String group, int lines, Renderer render, String codec)
100            throws InterruptedException {
101        LogRecord<Record>[] records = new LogRecord[lines];
102        render.header();
103        int count = 0;
104        try (LogTailer<Record> tailer = manager.createTailer(group, name, getRecordCodec(codec))) {
105            LogRecord<Record> record;
106            do {
107                record = tailer.read(Duration.ofMillis(500));
108                if (record != null) {
109                    records[count++ % lines] = record;
110                }
111            } while (record != null);
112        }
113        for (int i = count; i < lines + count; i++) {
114            LogRecord<Record> record = records[i % lines];
115            if (record != null) {
116                render.accept(record);
117            }
118        }
119        render.footer();
120    }
121
122    protected void follow(LogManager manager, String name, String group, Renderer render, int timeout, String codec)
123            throws InterruptedException {
124        try (LogTailer<Record> tailer = manager.createTailer(group, name, getRecordCodec(codec))) {
125            tailer.toEnd();
126            while (true) {
127                LogRecord<Record> record = tailer.read(Duration.ofSeconds(timeout));
128                if (record == null) {
129                    log.error("tail timeout");
130                    break;
131                }
132                render.accept(record);
133            }
134        }
135    }
136}