lttng-tools-java/src/main/java/org/lttng/tools/LttngCommandLineSession.java

   1 /*
   2  * Copyright (C) 2015, EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 package org.lttng.tools;
  20
  21 import static org.lttng.tools.utils.ShellUtils.executeCommand;
  22
  23 import java.util.Arrays;
  24 import java.util.List;
  25 import java.util.UUID;
  26 import java.util.stream.Collectors;
  27
  28 import org.lttng.tools.utils.ShellUtils;
  29
  30 /**
  31  * Implementation of {@link ILttngSession} which uses the command-line "lttng"
  32  * tool to manipulate the session. Creating an instance will run "lttng create",
  33  * close()'ing it will run "lttng destroy".
  34  *
  35  * @author Alexandre Montplaisir
  36  */
  37 class LttngCommandLineSession implements ILttngSession {
  38
  39     private final String sessionName;
  40     private final Domain domain;
  41
  42     private volatile boolean channelCreated = false;
  43
  44     /**
  45      * Constructor to create a new LTTng tracing session.
  46      *
  47      * @param sessionName
  48      *            The name of the session to use. It can be null, in which case
  49      *            we will provide a unique random name.
  50      * @param domain
  51      *            The tracing domain of this session
  52      */
  53     public LttngCommandLineSession(String sessionName, Domain domain) {
  54         if (sessionName != null) {
  55             this.sessionName = sessionName;
  56         } else {
  57             this.sessionName = UUID.randomUUID().toString();
  58         }
  59         this.domain = domain;
  60
  61         /* Create the session in LTTng */
  62         executeCommand(Arrays.asList("lttng", "create", this.sessionName));
  63     }
  64
  65     @Override
  66     public void close() {
  67         /* Destroy the session */
  68         executeCommand(Arrays.asList("lttng", "destroy", sessionName));
  69      // FIXME also delete the trace we generated ?
  70     }
  71
  72     @Override
  73     public boolean enableAllEvents() {
  74         channelCreated = true;
  75         return executeCommand(Arrays.asList(
  76                 "lttng", "enable-event", domain.flag(), "-a", "-s", sessionName));
  77     }
  78
  79     @Override
  80     public boolean enableEvents(String... enabledEvents) {
  81         if (enabledEvents == null || enabledEvents.length == 0) {
  82             throw new IllegalArgumentException();
  83         }
  84         channelCreated = true;
  85         return executeCommand(Arrays.asList(
  86                 "lttng", "enable-event", domain.flag(),
  87                 Arrays.stream(enabledEvents).collect(Collectors.joining(",")),
  88                 "-s", sessionName));
  89     }
  90
  91     @Override
  92     public boolean disableEvents(String... disabledEvents) {
  93         if (disabledEvents == null || disabledEvents.length == 0) {
  94             throw new IllegalArgumentException();
  95         }
  96         return executeCommand(Arrays.asList(
  97                 "lttng", "disable-event", domain.flag(),
  98                 Arrays.stream(disabledEvents).collect(Collectors.joining(",")),
  99                 "-s", sessionName));
 100     }
 101
 102     @Override
 103     public boolean start() {
 104         /*
 105          * We have to enable a channel for 'lttng start' to work. However, we
 106          * cannot enable a channel directly, see
 107          * https://bugs.lttng.org/issues/894 . Instead we will enable an event
 108          * we know does not exist
 109          */
 110         if (!channelCreated) {
 111             enableEvents("non-event");
 112         }
 113         return executeCommand(Arrays.asList("lttng", "start", sessionName));
 114     }
 115
 116     @Override
 117     public boolean stop() {
 118         return executeCommand(Arrays.asList("lttng", "stop", sessionName));
 119     }
 120
 121     @Override
 122     public List<String> view() {
 123         return ShellUtils.getOutputFromCommand(true, Arrays.asList("lttng", "view", sessionName));
 124     }
 125 }