| 1 | package org.lttng.ust.agent.utils; |
| 2 | |
| 3 | import java.io.IOException; |
| 4 | import java.lang.ProcessBuilder.Redirect; |
| 5 | import java.nio.file.Files; |
| 6 | import java.nio.file.Path; |
| 7 | import java.util.Arrays; |
| 8 | import java.util.List; |
| 9 | import java.util.stream.Collectors; |
| 10 | |
| 11 | public final class LttngSessionControl { |
| 12 | |
| 13 | private LttngSessionControl() {} |
| 14 | |
| 15 | public enum Domain { |
| 16 | JUL("-j"), |
| 17 | LOG4J("-l"); |
| 18 | |
| 19 | private final String flag; |
| 20 | |
| 21 | private Domain(String flag) { |
| 22 | this.flag = flag; |
| 23 | } |
| 24 | |
| 25 | public String flag() { |
| 26 | return flag; |
| 27 | } |
| 28 | } |
| 29 | |
| 30 | // ------------------------------------------------------------------------ |
| 31 | // Public utility methods |
| 32 | // ------------------------------------------------------------------------ |
| 33 | |
| 34 | /** |
| 35 | * Setup a LTTng session by enabling certain events (or none). |
| 36 | * |
| 37 | * @param sessionName |
| 38 | * The name of the session to create. May be null to use the |
| 39 | * default one from lttng-tools. |
| 40 | * @param domain |
| 41 | * The tracing domain |
| 42 | * @param enabledEvents |
| 43 | * The list of events to enable. May be null or empty, to not |
| 44 | * enable any events. |
| 45 | * @return If the command executed successfully (return code = 0). |
| 46 | */ |
| 47 | public static boolean setupSession(String sessionName, Domain domain, String... enabledEvents) { |
| 48 | String[] createCommand = (sessionName == null ? |
| 49 | new String[] { "lttng", "create" } : |
| 50 | new String[] { "lttng", "create", sessionName} |
| 51 | ); |
| 52 | |
| 53 | String eventsToEnable = (enabledEvents == null || enabledEvents.length == 0 ? |
| 54 | /* |
| 55 | * We have to enable a channel for 'lttng start' to work. |
| 56 | * However, we cannot enable a channel directly, see |
| 57 | * https://bugs.lttng.org/issues/894 . Instead we will enable an |
| 58 | * event we know does not exist |
| 59 | */ |
| 60 | "non-event" : |
| 61 | Arrays.stream(enabledEvents).collect(Collectors.joining(",")) |
| 62 | ); |
| 63 | |
| 64 | return executeCommands(new String[][] { |
| 65 | createCommand, |
| 66 | { "lttng", "enable-event", domain.flag(), eventsToEnable}, |
| 67 | { "lttng", "start" } |
| 68 | }); |
| 69 | } |
| 70 | |
| 71 | /** |
| 72 | * Setup a LTTng session with all events enabled (lttng enable-event -a). |
| 73 | * |
| 74 | * @param sessionName |
| 75 | * The name of the session to create. May be null to use the |
| 76 | * default one from lttng-tools. |
| 77 | * @param domain |
| 78 | * The tracing domain |
| 79 | * @return If the command executed successfully (return code = 0). |
| 80 | */ |
| 81 | public static boolean setupSessionAllEvents(String sessionName, Domain domain) { |
| 82 | String[] createCommand = (sessionName == null ? |
| 83 | new String[] { "lttng", "create" } : |
| 84 | new String[] { "lttng", "create", sessionName} |
| 85 | ); |
| 86 | |
| 87 | return executeCommands(new String[][] { |
| 88 | createCommand, |
| 89 | { "lttng", "enable-event", domain.flag(), "-a" }, |
| 90 | { "lttng", "start" } |
| 91 | }); |
| 92 | } |
| 93 | |
| 94 | /** |
| 95 | * Stop the current tracing session |
| 96 | * |
| 97 | * @return If the command executed successfully (return code = 0). |
| 98 | */ |
| 99 | public static boolean stopSession() { |
| 100 | return executeCommand(new String[] { "lttng", "stop" }); |
| 101 | } |
| 102 | |
| 103 | public static List<String> viewSession() { |
| 104 | return getOutputFromCommand(new String[] { "lttng", "view" }); |
| 105 | } |
| 106 | |
| 107 | /** |
| 108 | * Destroy the current tracing session |
| 109 | * |
| 110 | * @return If the command executed successfully (return code = 0). |
| 111 | */ |
| 112 | public static boolean destroySession() { |
| 113 | return executeCommand(new String[] { "lttng", "destroy" }); |
| 114 | } |
| 115 | |
| 116 | // ------------------------------------------------------------------------ |
| 117 | // Private helper methods |
| 118 | // ------------------------------------------------------------------------ |
| 119 | |
| 120 | private static boolean executeCommands(String [][] commands) { |
| 121 | for (String[] command : commands) { |
| 122 | if (executeCommand(command) == false) { |
| 123 | return false; |
| 124 | } |
| 125 | } |
| 126 | return true; |
| 127 | } |
| 128 | |
| 129 | /** |
| 130 | * Just to test the environment / stdout are working correctly |
| 131 | */ |
| 132 | public static void main(String[] args) { |
| 133 | executeCommand(new String[] {"ls", "-l"}); |
| 134 | } |
| 135 | |
| 136 | private static boolean executeCommand(String[] command) { |
| 137 | try { |
| 138 | ProcessBuilder builder = new ProcessBuilder(command); |
| 139 | builder.redirectErrorStream(true); |
| 140 | builder.redirectOutput(Redirect.INHERIT); |
| 141 | |
| 142 | Process p = builder.start(); |
| 143 | int ret = p.waitFor(); |
| 144 | return (ret == 0); |
| 145 | |
| 146 | } catch (IOException | InterruptedException e) { |
| 147 | return false; |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | private static List<String> getOutputFromCommand(String[] command) { |
| 152 | try { |
| 153 | Path tempFile = Files.createTempFile("test-output", null); |
| 154 | |
| 155 | ProcessBuilder builder = new ProcessBuilder(command); |
| 156 | builder.redirectErrorStream(true); |
| 157 | builder.redirectOutput(Redirect.to(tempFile.toFile())); |
| 158 | |
| 159 | Process p = builder.start(); |
| 160 | p.waitFor(); |
| 161 | |
| 162 | List<String> lines = Files.readAllLines(tempFile); |
| 163 | Files.delete(tempFile); |
| 164 | |
| 165 | /* Also print the output to the console */ |
| 166 | lines.stream().forEach(s -> System.out.println(s)); |
| 167 | |
| 168 | return lines; |
| 169 | |
| 170 | } catch (IOException | InterruptedException e) { |
| 171 | return null; |
| 172 | } |
| 173 | } |
| 174 | } |