Logback SMTPAppender在特定时间只发送一封电子邮件,但有所有例外

Question

有没有办法配置SMTPAppenderLogBack以满足以下条件？

1. 将所有异常分组到一条消息中
2. 如果发生异常,则仅发送每日日志报告
3. 仅在一天中的特定时间将报告发送一次,在一封电子邮件中分组.

我目前的实现远不是上面做的,但是当发生异常时它会发送3封电子邮件 - 异常消息,堆栈跟踪和缓冲区刷新.

<!-- Filter duplicate Log Messages - Very important for Email Reports -->
<turboFilter class="ch.qos.logback.classic.turbo.DuplicateMessageFilter">
    <AllowedRepetitions>1</AllowedRepetitions>
    <CacheSize>1000</CacheSize>
</turboFilter>

<!--
    ############################################################
            BASIC APPENDER
    ############################################################
-->

<appender name="Console" class="ch.qos.logback.core.ConsoleAppender">
    <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
        <pattern>%d{HH:mm:ss.SSS} %-55(%X{user} %level [%thread] %logger{20}) - %msg%n</pattern>
    </encoder>
</appender>


<!--
    ############################################################
            EMAIL APPENDER
    ############################################################
-->
<statusListener class="ch.qos.logback.core.status.OnConsoleStatusListener" />

<appender name="Email" class="ch.qos.logback.classic.net.SMTPAppender">
    <smtpHost>SERVER</smtpHost>
    <smtpPort>PORT</smtpPort>
    <asynchronousSending>false</asynchronousSending>
    <from>SENDER</from>
    <to>RECIPIENT</to>
    <subject>SUBJECT</subject>

    <layout class="ch.qos.logback.classic.PatternLayout">
        <pattern>%d{HH:mm:ss.SSS} %-55(%X{user} %level [%thread] %logger{20}) - %msg%n</pattern>
    </layout>

</appender>

<!--
    ############################################################
            OTHER
    ############################################################
-->
<root level="INFO">
    <appender-ref ref="Console"/>
    <appender-ref ref="RollingFile"/>
    <appender-ref ref="Email"/>
</root>

Answer 1

一个简单的解决方案是将这些错误记录到文件中,并在服务器/计算机上安装一个脚本,该脚本每天读取一次文件并发送电子邮件.

如果你想使用一个appender,在我看来你需要自己动手,因为我认为标准不能SMTPAppender让你每天发送一次电子邮件:

• 延伸 SMTPAppender
• 覆盖其中的sendBuffer方法,SMTPAppenderBase以便只将日志消息添加到集合中
• 添加一个每天ScheduledExecutorService运行一次sendEmail方法的appender
• 该sendEmail方法将同步this线程安全,检查集合是否为空,发送包含所有错误的电子邮件并清除集合

基本实现可能看起来像下面的类(我没有测试过它 - 我使用的是Java 8语法,但如果需要,可以用匿名类替换它).请注意,我只保留导致异常的事件,您可能还希望在sendBuffer方法中保留CyclicBuffer的内容和/或在sendEmail方法中的错误之间添加一些错误分隔符.这可能变得非常复杂,需要根据您的要求进行微调.

public class ScheduledSMTPAppender extends SMTPAppender {
  private final ThreadFactory tf = r -> {
    Thread t = new Thread(r, "ScheduledSMTPAppender Thread");
    t.setDaemon(true); //make daemon or it will prevent your program to exit
    return t;
  };
  private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1, tf);
  private final List<ILoggingEvent> events = new ArrayList<> ();

  private int maxMessages = 10;

  public ScheduledSMTPAppender() { super(); }
  public ScheduledSMTPAppender(EventEvaluator<ILoggingEvent> eventEvaluator) { super(eventEvaluator); }

  @Override public void start() {
    super.start();
    scheduler.scheduleAtFixedRate(this::sendEmail, 1, 1, TimeUnit.DAYS);
  }

  @Override protected void sendBuffer(CyclicBuffer<ILoggingEvent> cb, ILoggingEvent lastEventObject) {
    events.add(lastEventObject);
    if (events.size() > maxMessages) sendEmail();
  }

  //needs to be synchronized for thread safety
  private synchronized void sendEmail() {
    try {
      if (events.isEmpty()) return;
      ILoggingEvent lastEvent = events.get(events.size() - 1);
      events.remove(events.size() - 1);
      CyclicBuffer<ILoggingEvent> cb;
      if (events.isEmpty()) {
        cb = new CyclicBuffer<>(1);
      } else {
        cb = new CyclicBuffer<>(events.size());
        for (ILoggingEvent e : events) cb.add(e);
      }
      super.sendBuffer(cb, lastEvent);
      events.clear();
    } catch (Exception e) {
      //Important to have a catch all here or the scheduled task will die
      addError("Error occurred while sending e-mail notification.", e);
    }
  }

  //this allows to make "maxMessages" a parameter of your appender
  public int getMaxMessages() { return maxMessages; }
  public void setMaxMessages(int maxMessages) { this.maxMessages = maxMessages; }
}

您的logback配置文件如下所示:

<appender name="Email" class="your.package.ScheduledSMTPAppender">
    <smtpHost>SERVER</smtpHost>
    <smtpPort>PORT</smtpPort>
    <asynchronousSending>false</asynchronousSending>
    <from>SENDER</from>
    <to>RECIPIENT</to>
    <subject>SUBJECT</subject>
    <maxMessages>10</maxMessages>

    <layout class="ch.qos.logback.classic.PatternLayout">
        <pattern>%d{HH:mm:ss.SSS} %-55(%X{user} %level [%thread] %logger{20}) - %msg%n</pattern>
    </layout>
</appender>

更进一步,您可以添加参数,例如发送日期的时间,每天的电子邮件数量等.