Logback SMTPAppender只发送最后一封电子邮件

Question

我试图使用Logback与SMTPAppender作为我的日志解决方案。我有一个评估附加到appender触发电子邮件发送每100个错误记录。在大多数情况下，这是正确的，但我注意到，如果我在一个循环中快速创建错误以触发多封电子邮件，那么只有最后一封电子邮件发送了正确的内容。这似乎是一个竞争条件，第一个电子邮件还没有完成创建/发送，第二个电子邮件覆盖了第一个创建。其他人有过这样的经历或找到了解决方案吗?我的logback配置附在下面。

<configuration>
    <appender name="emailAppender" class="${logback.emailAppenderClass}">
       <evaluator class="com.wdp.common.logging.logback.evaluators.CountingLoggerEvaulator">
            <limit>100</limit>
        </evaluator>
        <to>${logback.emailNotificationRecipientStr}</to>
        <from>${logback.emailNotificationFromStr}</from>
        <smtpHost>${logback.smtpHost}</smtpHost>
        <subject>Logback logs for facebook-ads-processes</subject>
        <filter class="ch.qos.logback.classic.filter.LevelFilter">
            <level>ERROR</level>
            <onMatch>ACCEPT</onMatch>
            <onMismatch>DENY</onMismatch>
        </filter>
        <layout class="ch.qos.logback.classic.PatternLayout">
            <pattern>%d [Thread:%t] %p [%c] - %m%n</pattern>
        </layout>  
            <cyclicBufferTracker class="ch.qos.logback.core.spi.CyclicBufferTracker">
            <bufferSize>${logback.cyclicBufferSize}</bufferSize>
        </cyclicBufferTracker>
    </appender>
</configuration>

这是求值器:

public class CountingLoggerEvaulator extends EventEvaluatorBase<ILoggingEvent> implements EventEvaluator<ILoggingEvent> {
    //if limit is not set in configuration, this will cause it to send one email for each message received.
    private int limit = 100;
    private int counter = 0;
    public void setLimit(int limit) {
        this.limit = limit;
    }
    public int getLimit() {
        return limit;
    }
    @Override
    public boolean evaluate(ILoggingEvent expr) throws NullPointerException, EvaluationException {
        counter++;
        if (counter == limit) {
            counter = 0;
            return true;
        } else {
            return false;
        }
    }
}

Answer 1

SMTPAppender的asynchronousSending属性默认为true。处理步骤我把它设为false，它就能正常工作了

Answer 2

您应该使您的评估器线程安全-例如使用AtomicInteger:

public class CountingLoggerEvaulator extends EventEvaluatorBase<ILoggingEvent> implements EventEvaluator<ILoggingEvent> {
    //if limit is not set in configuration, this will cause it to send one email for each message received.
    private int limit = 100;
    private AtomicInteger counter = new AtomicInteger();
    public void setLimit(int limit) {
        this.limit = limit;
    }
    public int getLimit() {
        return limit;
    }
    @Override
    public boolean evaluate(ILoggingEvent expr) throws NullPointerException, EvaluationException {
        int curValue = counter.incrementAndGet();
        if (curValue >= limit) {
            return counter.compareAndSet(curValue, 0);
        } else {
            return false;
        }
    }
}