logback邮箱配置更改热更新

在DappSmtpAppender 中 重写了 parseAddress 方法，改成从 配置 中获取邮箱的配置， 支持热更新。

Code

import ch.qos.logback.classic.PatternLayout;
import ch.qos.logback.classic.net.SMTPAppender;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.CoreConstants;
import ch.qos.logback.core.Layout;
import ch.qos.logback.core.boolex.EvaluationException;
import ch.qos.logback.core.helpers.CyclicBuffer;
import ch.qos.logback.core.net.SMTPAppenderBase;
import ch.qos.logback.core.pattern.PatternLayoutBase;
import ch.qos.logback.core.util.ContentTypeUtil;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMultipart;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * 
 * 修改mimeMsg.setHeader的时机,避免并发造成的标题覆盖
 *
 * 继承自SMTPAppender并且覆盖了源有的makeSubjectLayout方法，
 * 这是为了实现程序中发送报警邮件的邮件标题修改功能。
 *
 * @author liuyudut.liu
 */
public class DappSmtpAppender extends SMTPAppender {


    private String charsetEncoding = "UTF-8";
    static InternetAddress[] EMPTY_IA_ARRAY = new InternetAddress[0];
    private static String HOST_NAME;
    private static String HOST_ADDRESS;
    private static AtomicInteger counter = new AtomicInteger(0);

    static {
        try {
            InetAddress localHost = InetAddress.getLocalHost();
            HOST_NAME = localHost.getHostName();
            HOST_ADDRESS = localHost.getHostAddress();
        } catch (UnknownHostException ignored) {
            HOST_NAME = "unknown-host";
            HOST_ADDRESS = "unknown-host";
        }
    }

    private String buildTitle(){
        return new StringBuilder().append(HOST_NAME)
                .append(" [ ").append(HOST_ADDRESS).append(" ]")
                .toString();
    }

    /**
     * 邮件主题, 检查是否有丢邮件的情况, 在标题题后面加了计数.
     */
    class SubjectLayout extends  PatternLayout{
        @Override
        public String doLayout(ILoggingEvent event) {
            return super.doLayout(event) + " " + counter.incrementAndGet();
        }
    }

    @Override
    protected Layout makeSubjectLayout(String subjectStr) {
        PatternLayout pl = new SubjectLayout();
        pl.setContext(getContext());
        pl.setPattern(buildTitle());
        pl.setPostCompileProcessor(null);
        pl.start();
        return pl;
    }

    final static int MAX_DELAY_BETWEEN_STATUS_MESSAGES = 1228800 * CoreConstants.MILLIS_IN_ONE_SECOND;
    int delayBetweenStatusMessages = 300 * CoreConstants.MILLIS_IN_ONE_SECOND;
    long lastTrackerStatusPrint = 0;
    private int errorCount = 0;

    private Object lock = new Object();

    /**
     * 这个方法和父类完全一样, 复写的原因是因为重写了SenderRunnable类
     * @param eventObject
     */
    protected void append(ILoggingEvent eventObject) {

        if (!checkEntryConditions()) {
            return;
        }

        String key = discriminator.getDiscriminatingValue(eventObject);
        long now = System.currentTimeMillis();
        final CyclicBuffer cb = cbTracker.getOrCreate(key, now);
        subAppend(cb, eventObject);
        try {
            if (eventEvaluator.evaluate(eventObject)) {
                // clone the CyclicBuffer before sending out asynchronously
                CyclicBuffer cbClone = new CyclicBuffer(cb);
                // see http://jira.qos.ch/browse/LBCLASSIC-221
                cb.clear();

                if (isAsynchronousSending()) {
                    // perform actual sending asynchronously
                    SenderRunnable senderRunnable = new SenderRunnable(cbClone, eventObject);
                    context.getExecutorService().execute(senderRunnable);
                } else {
                    // synchronous sending
                    sendBuffer(cbClone, eventObject);
                }
            }
        } catch (EvaluationException ex) {
            errorCount++;
            if (errorCount < CoreConstants.MAX_ERROR_COUNT) {
                addError("SMTPAppender's EventEvaluator threw an Exception-", ex);
            }
        }

        // immediately remove the buffer if asked by the user
        if (eventMarksEndOfLife(eventObject)) {
            cbTracker.endOfLife(key);
        }

        cbTracker.removeStaleComponents(now);

        if (lastTrackerStatusPrint + delayBetweenStatusMessages < now) {
            addInfo("SMTPAppender [" + name + "] is tracking [" + cbTracker.getComponentCount() + "] buffers");
            lastTrackerStatusPrint = now;
            // quadruple 'delay' assuming less than max delay
            if (delayBetweenStatusMessages < MAX_DELAY_BETWEEN_STATUS_MESSAGES) {
                delayBetweenStatusMessages *= 4;
            }
        }
    }

    /**
     * 因为邮箱服务端有限制, 所以连续的logger.error最终只有一个会发出邮件
     * 猜测可能是服务器一段时间内(经反复实验, 应该小于100ms) 收到的第一封/最后一封邮件
     * 又因为是异步发送, 所以就相当于随机了.
     *
     * 所以重新实现了父类当中的SenderRunnable, run方法中获取了锁(此类单例), 并在每发一封邮件之后, 休眠100ms
     *
     * 标题挪到同步块中,防止并发造成的标题覆盖
     */
    class SenderRunnable implements Runnable {

        final CyclicBuffer cyclicBuffer;
        final ILoggingEvent e;

        SenderRunnable(CyclicBuffer cyclicBuffer, ILoggingEvent e) {
            this.cyclicBuffer = cyclicBuffer;
            this.e = e;
        }

        public void run() {
            synchronized (lock) {
                try {
                    mimeMsg.setHeader("From", e.getLoggerName() + "@demo.com");
                    sendBuffer(cyclicBuffer, e);
                    TimeUnit.MILLISECONDS.sleep(100);
                } catch (InterruptedException ignored) {
                } catch (MessagingException ignored){
                }
            }
        }
    }

    /**
     * 这个方法和父类完全一样, 复写的原因是因为重写了SenderRunnable类
     *
     */
    protected void sendBuffer(CyclicBuffer cb, ILoggingEvent lastEventObject) {

        // Note: this code already owns the monitor for this
        // appender. This frees us from needing to synchronize on 'cb'.
        try {
            MimeBodyPart part = new MimeBodyPart();

            StringBuffer sbuf = new StringBuffer();

            String header = layout.getFileHeader();
            if (header != null) {
                sbuf.append(header);
            }
            String presentationHeader = layout.getPresentationHeader();
            if (presentationHeader != null) {
                sbuf.append(presentationHeader);
            }
            fillBuffer(cb, sbuf);
            String presentationFooter = layout.getPresentationFooter();
            if (presentationFooter != null) {
                sbuf.append(presentationFooter);
            }
            String footer = layout.getFileFooter();
            if (footer != null) {
                sbuf.append(footer);
            }

            String subjectStr = "Undefined subject";
            if (subjectLayout != null) {
                subjectStr = subjectLayout.doLayout(lastEventObject);

                // The subject must not contain new-line characters, which cause
                // an SMTP error (LOGBACK-865). Truncate the string at the first
                // new-line character.
                int newLinePos = (subjectStr != null) ? subjectStr.indexOf('\n') : -1;
                if (newLinePos > -1) {
                    subjectStr = subjectStr.substring(0, newLinePos);
                }
            }
            mimeMsg.setSubject(subjectStr, charsetEncoding);

            List destinationAddresses = parseAddress(lastEventObject);
            if (destinationAddresses.isEmpty()) {
                addInfo("Empty destination address. Aborting email transmission");
                return;
            }

            InternetAddress[] toAddressArray = destinationAddresses.toArray(EMPTY_IA_ARRAY);
            mimeMsg.setRecipients(Message.RecipientType.TO, toAddressArray);

            String contentType = layout.getContentType();

            if (ContentTypeUtil.isTextual(contentType)) {
                part.setText(sbuf.toString(), charsetEncoding, ContentTypeUtil
                        .getSubType(contentType));
            } else {
                part.setContent(sbuf.toString(), layout.getContentType());
            }

            Multipart mp = new MimeMultipart();
            mp.addBodyPart(part);
            mimeMsg.setContent(mp);

            mimeMsg.setSentDate(new Date());
            addInfo("About to send out SMTP message \"" + subjectStr + "\" to " + Arrays.toString(toAddressArray));
            Transport.send(mimeMsg);
        } catch (Exception e) {
            addError("Error occurred while sending e-mail notification.", e);
        }
    }

    private List parseAddress(ILoggingEvent event) {

        List iaList = new ArrayList();
        iaList.addAll( MailAddConfig.getInternetAddress() ) ;
        return iaList;

    }

}

对应的分布式配置中心的 类：MailAddConfig， 就可以动态获取

修改logback的配置xml ，新增 自定义的 appender

Code

    xxxx.xxxx.xxxx.xxxx

    xxxx.xxxx@xxxx.com