vy commented on a change in pull request #452: URL: https://github.com/apache/logging-log4j2/pull/452#discussion_r554011768
########## File path: log4j-core/src/main/java/org/apache/logging/log4j/core/appender/AsyncAppenderEventDispatcher.java ########## @@ -0,0 +1,172 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache license, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the license for the specific language governing permissions and + * limitations under the license. + */ +package org.apache.logging.log4j.core.appender; + +import org.apache.logging.log4j.Logger; +import org.apache.logging.log4j.core.LogEvent; +import org.apache.logging.log4j.core.config.AppenderControl; +import org.apache.logging.log4j.core.impl.Log4jLogEvent; +import org.apache.logging.log4j.core.util.Log4jThread; +import org.apache.logging.log4j.status.StatusLogger; + +import java.util.List; +import java.util.concurrent.BlockingQueue; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.concurrent.atomic.AtomicLong; + +class AsyncAppenderEventDispatcher extends Log4jThread { + + private static final LogEvent STOP_EVENT = new Log4jLogEvent(); + + private static final AtomicLong THREAD_COUNTER = new AtomicLong(0); + + private static final Logger LOGGER = StatusLogger.getLogger(); + + private final AppenderControl errorAppender; + + private final List<AppenderControl> appenders; + + private final BlockingQueue<LogEvent> queue; + + private final AtomicBoolean stoppedRef; + + AsyncAppenderEventDispatcher( + final String name, + final AppenderControl errorAppender, + final List<AppenderControl> appenders, + final BlockingQueue<LogEvent> queue) { + super("AsyncAppenderEventDispatcher-" + THREAD_COUNTER.incrementAndGet() + "-" + name); + this.errorAppender = errorAppender; + this.appenders = appenders; + this.queue = queue; + this.stoppedRef = new AtomicBoolean(false); + } + + @Override + public void run() { + LOGGER.trace("{} has started.", getName()); + dispatchAll(); + dispatchRemaining(); + } + + private void dispatchAll() { + while (!stoppedRef.get()) { + LogEvent event; + try { + event = queue.take(); + } catch (final InterruptedException ignored) { + // Restore the interrupted flag cleared when the exception is caught. + interrupt(); + break; + } + if (event == STOP_EVENT) { + break; + } + event.setEndOfBatch(queue.isEmpty()); + dispatch(event); + } + LOGGER.trace("{} has stopped.", getName()); + } + + private void dispatchRemaining() { + int eventCount = 0; + while (true) { + // Note the non-blocking Queue#poll() method! + final LogEvent event = queue.poll(); + if (event == null || event == STOP_EVENT) { + break; + } + event.setEndOfBatch(queue.isEmpty()); + dispatch(event); + eventCount++; + } + LOGGER.trace( + "{} has processed the last {} remaining event(s).", + getName(), eventCount); + } + + void dispatch(final LogEvent event) { + + // Dispatch the event to all registered appenders. + boolean succeeded = false; + // noinspection ForLoopReplaceableByForEach (avoid iterator instantion) + for (int appenderIndex = 0; appenderIndex < appenders.size(); appenderIndex++) { + final AppenderControl control = appenders.get(appenderIndex); + try { + control.callAppender(event); + succeeded = true; + } catch (final Throwable error) { + // If no appender is successful, the error appender will get it. + // It is okay to simply log it here. + if (LOGGER.isTraceEnabled()) { + final String message = String.format( + "%s has failed to call appender %s", + getName(), control.getAppenderName()); + LOGGER.trace(message, error); Review comment: Here I try to match against the `trace(..., Throwable)` method. How can I employ *interpolation curly braces* to achieve that? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
