Why is Logback SMTPAppender only sending 1 email?

Here's a snippet containing my Logback SMTPAppender:

<appender name="logManager-smtpAppender" class="ch.qos.logback.classic.net.SMTPAppender">
    <filter class="ch.qos.logback.classic.filter.LevelFilter">
        <level>WARN</level>
        <onMatch>ACCEPT</onMatch>
        <onMismatch>NEUTRAL</onMismatch>
    </filter>
    <filter class="ch.qos.logback.classic.filter.LevelFilter">
        <level>ERROR</level>
        <onMatch>ACCEPT</onMatch>
        <onMismatch>DENY</onMismatch>
    </filter>

    <asynchronousSending>false</asynchronousSending>

    <smtpHost>my.smtp.host</smtpHost>
    <to>[email protected]</to>
    <from>[email protected]</from>
    <username>my_smtp_user</username>
    <password>my_smtp_password</password>
    <subject>%logger{20} - %m</subject>
    <layout class="ch.qos.logback.classic.html.HTMLLayout"/>
    <cyclicBufferTracker class="ch.qos.logback.core.spi.CyclicBufferTracker">
        <bufferSize>1</bufferSize>
    </cyclicBufferTracker>
</appender>

When the following Java executes:

logger.warn("This is a warning.");
logger.error("This is an error.");

I only get 1 email. By setting bufferSize to 1 I would have expected to get 2 different emails with 1 single log message in each of them. What's going on?

Solution

As Ceki has already mentioned that SMTPAPpender trigges emails on events of level ERROR. To get all your logs in one mail, You can increase the buffersize

Here by increasing bufferSize to 10, You will get last 10 messages logged by your error.

Check below link : https://github.com/abdulwaheed18/Slf4jTutorial/blob/master/src/com/waheed/tutorial8/Application8.java https://github.com/abdulwaheed18/Slf4jTutorial/blob/master/sample8.xml