My EvaluatorFilter doesn't work in Spring Boot + logback-access.xml

Question

I've managed to integrate logback-access.xml with a Spring Boot on Tomcat project but for the life of me I cannot get it to respect my ch.qos.logback.core.filter.EvaluatorFilter. It definitely sees and uses my logback-access.xml file (if I change the encoder.pattern the output messages change), but seems oblivious of the filter I configure there; I don't get the effect I am looking for which is suppression of any access log messages from the /healthz URL and I don't see my System.out.println cry for help

The logback-access.xml file looks like

<configuration>
    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
        <filter class="ch.qos.logback.core.filter.EvaluatorFilter">
            <evaluator>
                <expression>
                    System.out.println("ROBERT!!!! " + formattedMessage);
                    return formattedMessage.contains("/healthz");
                </expression>
            </evaluator>
            <OnMismatch>NEUTRAL</OnMismatch>
            <OnMatch>DENY</OnMatch>
        </filter>
        <encoder>
            <pattern>%h %l %u %user %date "%r" %s %b</pattern>
        </encoder>
    </appender>
    <appender-ref ref="CONSOLE"/>
</configuration>

The build.gradle has the requisite dependencies

    compile(group: 'net.rakugakibox.springbootext', name: 'spring-boot-ext-logback-access', version: '1.6')
    compile group: 'org.codehaus.janino', name: 'janino', version: '3.0.7'

The logging output mocks me...

0:0:0:0:0:0:0:1 - - - 22/Jun/2017:15:16:17 -0700 "GET /healthz HTTP/1.1" 200 27
0:0:0:0:0:0:0:1 - - - 22/Jun/2017:15:18:18 -0700 "GET /v1/scouting_activities/fcdc7aae-4f11-4476-bb81-6d5e3f52e1b4 HTTP/1.1" 200 1939

How do I get an ch.qos.logback.core.filter.EvaluatorFilter in logback-access.xml under Spring Boot 1.4.1 to work and skip the GET /healthz requests?

Answer 1

If you debug the logback configuration you will see the problem(<configuration debug="true">).

11:03:53,559 |-ERROR in ch.qos.logback.access.boolex.JaninoEventEvaluator@649725e3 - Could not start evaluator with expression [System.out.println("ROBERT!!!! " + formattedMessage);
                    return false;] org.codehaus.commons.compiler.CompileException: Line 1, Column 52: Expression "formattedMessage" is not an rvalue
    at org.codehaus.commons.compiler.CompileException: Line 1, Column 52: Expression "formattedMessage" is not an rvalue

The problem is that logback-access does not operate on ILoggingEvent, rather it operates on IAccessEvent.

There are JaninoEventEvaluator classes for each type of event.
The logback-access evaluator does not have the formattedMessage value.

It does however have the event value which is an instance of a IAccessEvent.

So just change your expression to the below and it should work.

<expression>
    System.out.println("ROBERT!!!! " + event.getRequestURI());
    return event.getRequestURI().contains("/healthz");
</expression>