| 1 | /* |
| 2 | * SPDX-License-Identifier: MIT |
| 3 | * |
| 4 | * Copyright (C) 2016 EfficiOS Inc. |
| 5 | * Copyright (C) 2016 Alexandre Montplaisir <alexmonthy@efficios.com> |
| 6 | */ |
| 7 | |
| 8 | import java.io.IOException; |
| 9 | import java.util.logging.Handler; |
| 10 | import java.util.logging.Logger; |
| 11 | |
| 12 | import org.lttng.ust.agent.context.ContextInfoManager; |
| 13 | import org.lttng.ust.agent.context.IContextInfoRetriever; |
| 14 | import org.lttng.ust.agent.jul.LttngLogHandler; |
| 15 | |
| 16 | /** |
| 17 | * Example program defining a application context retriever, which allows |
| 18 | * attaching application-defined contexts to trace events. |
| 19 | * |
| 20 | * FIXME Use custom context names, and several names/types |
| 21 | * |
| 22 | * <p> |
| 23 | * Usage: |
| 24 | * <ul> |
| 25 | * <li>$ lttng create</li> |
| 26 | * <li>$ lttng enable-event -j -a</li> |
| 27 | * <li>$ lttng add-context -j -t '$app.myprovider:mystringcontext'</li> |
| 28 | * <li>$ lttng add-context -j -t '$app.myprovider:myshortcontext'</li> |
| 29 | * <li>$ lttng start</li> |
| 30 | * <li>(run this program)</li> |
| 31 | * <li>$ lttng stop</li> |
| 32 | * <li>$ lttng view</li> |
| 33 | * <li>$ lttng destroy</li> |
| 34 | * </ul> |
| 35 | * </p> |
| 36 | * |
| 37 | * The events present in the resulting trace should carry the context |
| 38 | * information defined in the example retriever. |
| 39 | * |
| 40 | * @author Alexandre Montplaisir |
| 41 | */ |
| 42 | public class ApplicationContextExample { |
| 43 | |
| 44 | /** Class-wide JUL logger object */ |
| 45 | private static final Logger LOGGER = Logger.getLogger(ApplicationContextExample.class.getName()); |
| 46 | |
| 47 | private static final String RETRIEVER_NAME = "myprovider"; |
| 48 | private static final String CONTEXT_NAME_STRING = "mystringcontext"; |
| 49 | private static final String CONTEXT_NAME_SHORT = "myshortcontext"; |
| 50 | |
| 51 | private static class ExampleContextInfoRetriever implements IContextInfoRetriever { |
| 52 | |
| 53 | @Override |
| 54 | public Object retrieveContextInfo(String key) { |
| 55 | if (CONTEXT_NAME_SHORT.equals(key)) { |
| 56 | return (short) 42; |
| 57 | } else if (CONTEXT_NAME_STRING.equals(key)) { |
| 58 | return "context-value!"; |
| 59 | } else { |
| 60 | return null; |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * Application start |
| 68 | * |
| 69 | * @param args |
| 70 | * Command-line arguments |
| 71 | * @throws IOException |
| 72 | * @throws InterruptedException |
| 73 | */ |
| 74 | public static void main(String args[]) throws IOException, InterruptedException { |
| 75 | /* Instantiate and attach a logger object */ |
| 76 | Handler lttngHandler = new LttngLogHandler(); |
| 77 | LOGGER.addHandler(lttngHandler); |
| 78 | |
| 79 | /* Instantiate and register the context retriever */ |
| 80 | IContextInfoRetriever cir = new ExampleContextInfoRetriever(); |
| 81 | ContextInfoManager.getInstance().registerContextInfoRetriever(RETRIEVER_NAME, cir); |
| 82 | |
| 83 | /* |
| 84 | * Make sure you have a LTTng session running with the appropriate |
| 85 | * events and contexts enabled! See the class Javadoc. |
| 86 | */ |
| 87 | |
| 88 | /* Trigger a tracing event using the JUL Logger created before. */ |
| 89 | LOGGER.info("Log event #1"); |
| 90 | LOGGER.warning("Log event #2"); |
| 91 | LOGGER.severe("Log event #3"); |
| 92 | |
| 93 | /* Unregister our context retriever, and dispose the log handler */ |
| 94 | ContextInfoManager.getInstance().unregisterContextInfoRetriever(RETRIEVER_NAME); |
| 95 | lttngHandler.close(); |
| 96 | } |
| 97 | } |