Repository: sentry Updated Branches: refs/heads/master 8f600a6a6 -> 7c5be79b4
SENTRY-2335: Allow sentry to have multiple handlers for a Signal (Brian Towles, reviewed by Na Li) Project: http://git-wip-us.apache.org/repos/asf/sentry/repo Commit: http://git-wip-us.apache.org/repos/asf/sentry/commit/7c5be79b Tree: http://git-wip-us.apache.org/repos/asf/sentry/tree/7c5be79b Diff: http://git-wip-us.apache.org/repos/asf/sentry/diff/7c5be79b Branch: refs/heads/master Commit: 7c5be79b4fdcc32afee95e56899a55786d8952a8 Parents: 8f600a6 Author: lina.li <lina...@cloudera.com> Authored: Thu Aug 9 18:14:00 2018 -0500 Committer: lina.li <lina...@cloudera.com> Committed: Thu Aug 9 18:14:00 2018 -0500 ---------------------------------------------------------------------- .../sentry/core/common/utils/SigUtils.java | 46 +++++++++++++------- 1 file changed, 31 insertions(+), 15 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/sentry/blob/7c5be79b/sentry-core/sentry-core-common/src/main/java/org/apache/sentry/core/common/utils/SigUtils.java ---------------------------------------------------------------------- diff --git a/sentry-core/sentry-core-common/src/main/java/org/apache/sentry/core/common/utils/SigUtils.java b/sentry-core/sentry-core-common/src/main/java/org/apache/sentry/core/common/utils/SigUtils.java index 1f16e14..d621c74 100644 --- a/sentry-core/sentry-core-common/src/main/java/org/apache/sentry/core/common/utils/SigUtils.java +++ b/sentry-core/sentry-core-common/src/main/java/org/apache/sentry/core/common/utils/SigUtils.java @@ -16,11 +16,14 @@ */ package org.apache.sentry.core.common.utils; -import sun.misc.Signal; -import sun.misc.SignalHandler; - +import java.util.HashMap; +import java.util.HashSet; +import java.util.Map; +import java.util.Set; import org.slf4j.Logger; import org.slf4j.LoggerFactory; +import sun.misc.Signal; +import sun.misc.SignalHandler; /** * This class facilitates handling signals in Sentry. @@ -34,14 +37,13 @@ import org.slf4j.LoggerFactory; * This class relies on sun.misc.SignalHandler which registers signal handlers via static * method handle(). Therefore, SigUtils also only exposes a static method registerListener() * <p> - * This class, as sun.misc.SignalHandler, supports a single signal listener per each signal. - * The same signal listener can be used to handle multiple signals, but setting a listener - * for the same signal twice will replace an old listener with the new one. - * method. + * This class, as sun.misc.SignalHandler, supports a multiple signal listeners per each signal. + * The same signal listener can be used to handle multiple signals. */ public final class SigUtils { private static final Logger LOGGER = LoggerFactory.getLogger(SigUtils.class); + private static Map<String, SigHandler> sigHandlerMap = new HashMap<>(); private SigUtils() {} // to prevent class instantiation @@ -56,14 +58,24 @@ public final class SigUtils { * to a registered signal listener. */ private static class SigHandler implements SignalHandler { - private final SigListener listener; - SigHandler(SigListener listener) { - this.listener = listener; + private final Set<SigListener> listeners = new HashSet<>(); + SigHandler() { + } + public void addListener(SigListener sigListener){ + listeners.add(sigListener); } @Override public void handle(Signal sig) { if (sig != null) { - listener.onSignal(sig.toString()); + for (SigListener listener : listeners) { + try { + LOGGER.debug("Running Signal Handler {}.onSignal()", listener.getClass().getName()); + listener.onSignal(sig.toString()); + } catch (Exception e) { + LOGGER.warn(String.format("Signal handler %s.onSignal() threw an exception:", + listener.getClass().getName()), e); + } + } // signalling is a rare yet important event - let's always log it LOGGER.info("Signal propagated: " + sig); } else { @@ -73,10 +85,9 @@ public final class SigUtils { } /** - * Register signal listener for a specific signal. + * Adds a signal listener for a specific signal. * - * Only one listener per specific signal is supported. Calling this method - * multiple times will keep overwriting a previously set listener. + * Multiple listeners per specific signal are supported but execution order is indeterminate. * * @NotNull sigName * @NotNull sigListener @@ -91,7 +102,12 @@ public final class SigUtils { if (sigName == null) { throw new IllegalArgumentException("NULL signal name"); } - Signal.handle(new Signal(sigName), new SigHandler(sigListener)); + if (!sigHandlerMap.containsKey(sigName)){ + sigHandlerMap.put(sigName, new SigHandler()); + } + SigHandler sigHandler = sigHandlerMap.get(sigName); + sigHandler.addListener(sigListener); + Signal.handle(new Signal(sigName), sigHandler); LOGGER.info("Signal Listener registered for signal " + sigName); } }
