java - 如何更新 Logback 中 SMTPAppender 上的 "to"地址？

Question

我正在创建一个管理页面，其中有几个我想即时设置的 logback 属性，其中之一是我向其发送系统警报的管理电子邮件。 SMTPAppender 的 api 具有添加到“收件人”地址列表或将它们作为列表获取的方法，但我没有找到任何要清除、删除或更新它们的方法。我应该怎么做？

我目前看到两个选项:

1. 一种选择是删除附加程序并创建一个具有新属性的新附加程序(糟糕)。
2. 弄清楚如何直接通过 Joran 进行配置(也许很糟糕？)。

我正在推进 (2)，但如果有更好的方法请发帖。

Answer 1

也许你已经完成了这个，但我只需要找到一种方法来设置动态“到”地址，这个主题引导我找到了方法(感谢@gresdiplitude 关于系统属性和 MDC 值的想法)，所以我正在分享我的解决方案。

我正在使用 SMTPAppender 发送小型执行报告，但这些需要发送到不同的邮箱。该解决方案看起来很简单，或者至少我对结果非常满意。

我的 logback.xml:

<!-- this is the trick: a converter to use on the "to" field pattern -->
<conversionRule conversionWord="smtpTo" converterClass="com.example.logback.MyConverter" />
<appender name="SMTP" class="ch.qos.logback.classic.net.SMTPAppender">
    <!-- a filter to select just the log entries that will be sent by mail -->
    <filter class="com.example.logback.MyFilter" />
    <!-- an evaluator, mine is like CounterBasedEvaluator from the manual:
        http://logback.qos.ch/xref/chapters/appenders/mail/CounterBasedEvaluator.html
    -->
    <evaluator class="com.example.logback.MyEvaluator">
        <limit>25</limit>
    </evaluator>
    <!-- a discriminator to create a cyclic buffer for each mailing group I need -->
    <discriminator class="com.example.logback.MyDiscriminator" />
    <!-- just matching buffer size to evaluator limit -->
    <cyclicBufferTracker class="ch.qos.logback.core.spi.CyclicBufferTrackerImpl">
        <bufferSize>25</bufferSize>
    </cyclicBufferTracker>
    <smtpHost>${smtp.host}</smtpHost>
    <smtpPort>${smtp.port}</smtpPort>
    <SSL>${smtp.ssl}</SSL>
    <username>${smtp.username}</username>
    <password>${smtp.password}</password>
    <from>${smtp.from}</from>

    <!-- here you use the converter: in this case will get data
        from marker containing the destination addresses
    -->
    <to>%smtpTo</to>
    <subject>my subject</subject>
    <layout class="ch.qos.logback.classic.PatternLayout">
        <pattern>%date: %message%n%xThrowable{full}</pattern>
    </layout>
</appender>

MyFilter.java:

public FilterReply decide(ILoggingEvent event) {
    return event.getMarker() != null
            && event.getMarker().contains("REPORT") ? FilterReply.ACCEPT
            : FilterReply.DENY;
}

MyDiscriminator.java:

public String getDiscriminatingValue(ILoggingEvent e) {
    Marker marker = e.getMarker();
    if (marker == null || !(marker instanceof MyMarker)) {
        return null;
    }
    return ((MyMarker) marker).getDiscriminatingValue();
}

MyConverter.java:

public class MyConverter extends ClassicConverter {

    @Override
    public String convert(ILoggingEvent event) {
        Marker marker = event.getMarker();
        if (marker == null || !(marker instanceof MyMarker)) {
            return null;
        }
        return ((MyMarker) marker).getSmtpTo();
    }
}

MyMarker.java:

public interface MyMarker extends Marker {
    // a list of destination addresses, like "a@c.com, x@y.net"
    String getSmtpTo();
    // an "id" to tell the buffers apart, could be "smtpTo" itself
    // but in my case it would mix different reports that goes to the same addresses
    String getDiscriminatingValue();
}

我刚刚为 MyMarker 创建了一个实现，并在每个应该报告的日志语句上使用了它的几个实例:

// suggestion: make the marker immutable, then you can store and reuse them instead of recreating them every time
Marker marker1 = new MyMarkerImpl(
    "REPORT", // marker name
    "me@company.com, joe@company.com", // smtpTo
    "alertGroup"); // discriminatingValue
logger.warn(marker1, "SNAFU");
Marker marker2 = new MyMarkerImpl(
    "REPORT", "boss@company.com, ceo@company.com", "phbGroup");
logger.info(marker2, "Everything is fine");
// here we have same smtpTo as above but different discriminatingValues, so this will be sent in another email/report
Marker marker3 = new MyMarkerImpl(
    "REPORT", "me@company.com, joe@company.com", "bugFixingGroup");
logger.error(marker3, "Why things gone bad", exception);

希望对你有用。