logback异步输出日志过程解读

package ch.qos.logback.core;
  
import ch.qos.logback.core.spi.ContextAware;
import ch.qos.logback.core.spi.FilterAttachable;
import ch.qos.logback.core.spi.LifeCycle;
  

public interface Appender<E> extends LifeCycle, ContextAware, FilterAttachable {

  public String getName();
  
  public void setName(String name);

 //核心方法：处理日志事件
  void doAppend(E event);
  
}

<configuration>
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
      <pattern>%-4relative [%thread] %-5level %logger{35} - %msg %n</pattern>
    </encoder>
  </appender>
  <root level="DEBUG">
       <appender-ref ref="STDOUT" />
  </root>
  </configuration>

<configuration>
  <appender name="FILE" class="ch.qos.logback.core.FileAppender">
    <!-- 日志文件名称 -->
    <file>testFile.log</file>
    <!-- 是否追加输出 -->
    <append>true</append>
    <!-- 立即刷新，设置成false可以提高日志吞吐量 -->
    <immediateFlush>true</immediateFlush>
    <encoder>
     <!-- 日志输出格式 -->
      <pattern>%-4relative [%thread] %-5level %logger{35} - %msg%n</pattern>
    </encoder>
  </appender>
        
  <root level="DEBUG">
    <appender-ref ref="FILE" />
  </root>
</configuration>

<configuration>
  <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <!-- 日志文件名称 -->
    <file>logFile.log</file>
    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
      <!-- 按天滚动生成历史日志文件 -->
      <fileNamePattern>logFile.%d{yyyy-MM-dd}.log</fileNamePattern>

      <!-- 历史日志文件保存的天数和容量大小-->
      <maxHistory>30</maxHistory>
      <totalSizeCap>3GB</totalSizeCap>
    </rollingPolicy>

    <encoder>
      <pattern>%-4relative [%thread] %-5level %logger{35} - %msg%n</pattern>
    </encoder>
  </appender> 

  <root level="DEBUG">
    <appender-ref ref="FILE" />
  </root>
</configuration>

AppenderAttachableImpl<E> aai = new AppenderAttachableImpl<E>();
BlockingQueue<E> blockingQueue;
AsyncAppenderBase<E>.Worker worker = new AsyncAppenderBase.Worker();

while (parent.isStarted()) {
    try {
        E e = parent.blockingQueue.take();    //单条循环
        aai.appendLoopOnAppenders(e);
    } catch (InterruptedException ie) {
        break;
    }
}

<configuration>
	  <appender name="FILE" class="ch.qos.logback.core.FileAppender">
	    <file>myapp.log</file>
	    <encoder>
	      <pattern>%logger{35} - %msg%n</pattern>
	    </encoder>
	  </appender>

	  <appender name="ASYNC" class="ch.qos.logback.classic.AsyncAppender">
	     <appender-ref ref="FILE" />
         <!-- 设置异步阻塞队列的大小，为了不丢失日志建议设置的大一些，单机压测时100000是没问题的，应该不用担心OOM -->
        <queueSize>10000</queueSize>
        <!-- 设置丢弃DEBUG、TRACE、INFO日志的阀值，不丢失 -->
        <discardingThreshold>0</discardingThreshold>
        <!-- 设置队列入队时非阻塞，当队列满时会直接丢弃日志，但是对性能提升极大 -->
        <neverBlock>true</neverBlock>
	  </appender>

	  <root level="DEBUG">
	    <appender-ref ref="ASYNC" />
	  </root>
 </configuration>