在akka中如何使用log

akka中显示日志不需要第三方jar, 直接使用akka的Logging即可, Logging默认是输出到STDOUT, 当然你也可以使用第三方插件如SLF4J来记录日志, Logging使用的异步方式以此来达到最小的性能损耗.

代码中使用Logging

import akka.actor.*;
import akka.event.Logging;
import akka.event.LoggingAdapter;


class MyActor extends UntypedActor {
  LoggingAdapter log = Logging.getLogger(getContext().system(), this);
  @Override
  public void preStart() {
    log.debug("Starting");
  }
  @Override
  public void preRestart(Throwable reason, Option<Object> message) {
    log.error(reason, "Restarting due to [{}] when processing [{}]",
      reason.getMessage(), message.isDefined() ? message.get() : "");
}
  public void onReceive(Object message) {
    if (message.equals("test")) {
      log.info("Received test");
    } else {
      log.warning("Received unknown message: {}", message);
    }
} }

Dead letters的log

akka中默认dead letters会以info的形式输出.你可以调整显示多少dead letter, 并在之后就不再显示这些log. 另外在程序shutdown时显示相应的dead letters.

akka {
  log-dead-letters = 10
  log-dead-letters-during-shutdown = on
}

调整logging的级别

 akka {
  loglevel = "DEBUG"
}

启动时显示相应的config

akka {
  # Log the complete configuration at INFO level when the actor system is started.
  # This is useful when you are uncertain of what configuration is used.
  log-config-on-start = on
}

如果希望非常详细的显示所有接受到的消息

akka { 
    actor {
        debug {
             # enable DEBUG logging of all AutoReceiveMessages (Kill, PoisonPill et.c.)
            autoreceive = on
        }
    } 
    
}

使用SLF4J

• maven中新增配置

  <dependency>
      <groupId>com.typesafe.akka</groupId>
      <artifactId>akka-slf4j_2.11</artifactId>
      <version>2.4.17</version>
  </dependency>
  <!-- https://mvnrepository.com/artifact/ch.qos.logback/logback-core -->
  

  ch.qos.logback logback-core 1.1.7 ch.qos.logback logback-classic 1.1.7

• resources/目录下新增logback.xml

  %d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n

      <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
          <fileNamePattern>logs\akka.%d{yyyy-MM-dd}.%i.log</fileNamePattern>
          <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
              <maxFileSize>50MB</maxFileSize>
          </timeBasedFileNamingAndTriggeringPolicy>
      </rollingPolicy>
  </appender>
  <!-- 控制台输出 -->   
  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
     <!-- 日志输出编码 -->  
     <Encoding>UTF-8</Encoding>   
      <layout class="ch.qos.logback.classic.PatternLayout">   
           <!--格式化输出：%d表示日期，%thread表示线程名，%-5level：级别从左显示5个字符宽度%msg：日志消息，%n是换行符--> 
          <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n</pattern>   
      </layout>
  </appender>
  
  <root level="DEBUG">
      <appender-ref ref="FILE" />
      <appender-ref ref="STDOUT"/>
  </root>
  

• 程序中使用

  private Logger log = LoggerFactory.getLogger(XXX.class);