Refine Logback XML support documentation

[kwencel]

From what I read here you started to support external Logback XML configuration in 0.11.0-RC1.

However, when I run a Spring Boot 2.6.0 app with 0.11.0-R1 Gradle plugin and removeXmlSupport set to false, with the following arguments:

-Duser.timezone=Europe/Warsaw
-Duser.language=pl
-Duser.country=PL
-Dcom.sun.management.jmxremote.port=3000
-Dcom.sun.management.jmxremote.rmi.port=3000
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false
-Djava.rmi.server.hostname=127.0.0.1
-Dcom.sun.management.jmxremote.local.only=true
-Dlogging.config=file:///app/config/logs/logback.xml
-Dserver.address=0.0.0.0
-Dserver.port=8080
-Dmanagement.server.address=0.0.0.0
-Dmanagement.server.port=8081
-Dmanagement.endpoints.web.base-path=/
-Dspring.config.additional-location=/app/config/
-Dspring.profiles.active=k8s

it displays the following message:

Logging system failed to initialize using configuration from 'file:///app/config/logs/logback.xml'
java.lang.IllegalStateException: Logback configuration error detected:
ERROR in ch.qos.logback.core.joran.action.AppenderAction - Could not create an Appender of type [ch.qos.logback.core.ConsoleAppender]. ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type ch.qos.logback.core.ConsoleAppender
ERROR in ch.qos.logback.core.joran.spi.Interpreter@9:71 - ActionException in Action for tag [appender] ch.qos.logback.core.joran.spi.ActionException: ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type ch.qos.logback.core.ConsoleAppender
ERROR in ch.qos.logback.core.joran.action.AppenderAction - Could not create an Appender of type [ch.qos.logback.core.ConsoleAppender]. ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type ch.qos.logback.core.ConsoleAppender
ERROR in ch.qos.logback.core.joran.spi.Interpreter@6:73 - ActionException in Action for tag [appender] ch.qos.logback.core.joran.spi.ActionException: ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type ch.qos.logback.core.ConsoleAppender
ERROR in ch.qos.logback.core.joran.action.AppenderRefAction - Could not find an appender named [STDOUT]. Did you define it below instead of above in the configuration file?
ERROR in ch.qos.logback.core.joran.action.AppenderRefAction - See http://logback.qos.ch/codes.html#appender_order for more details.
    at org.springframework.boot.logging.logback.LogbackLoggingSystem.loadConfiguration(LogbackLoggingSystem.java:179)
    at org.springframework.boot.logging.AbstractLoggingSystem.initializeWithSpecificConfig(AbstractLoggingSystem.java:66)
    at org.springframework.boot.logging.AbstractLoggingSystem.initialize(AbstractLoggingSystem.java:57)
    at org.springframework.boot.logging.logback.LogbackLoggingSystem.initialize(LogbackLoggingSystem.java:132)
    at org.springframework.boot.context.logging.LoggingApplicationListener.initializeSystem(LoggingApplicationListener.java:316)
    at org.springframework.boot.context.logging.LoggingApplicationListener.initialize(LoggingApplicationListener.java:282)
    at org.springframework.boot.context.logging.LoggingApplicationListener.onApplicationEnvironmentPreparedEvent(LoggingApplicationListener.java:240)
    at org.springframework.boot.context.logging.LoggingApplicationListener.onApplicationEvent(LoggingApplicationListener.java:216)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:176)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:169)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:143)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:131)
    at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:85)
    at org.springframework.boot.SpringApplicationRunListeners.lambda$environmentPrepared$2(SpringApplicationRunListeners.java:66)
    at java.util.ArrayList.forEach(ArrayList.java:1541)
    at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:120)
    at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:114)
    at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:65)
    at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:338)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:296)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1301)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1290)
    at <redacted>.ApplicationKt.main(Application.kt:51)

The /app/config/logs/logback.xml looks looks like this:

<configuration>
  <include resource="org/springframework/boot/logging/logback/defaults.xml"/>
  <include resource="org/springframework/boot/logging/logback/console-appender.xml"/>

  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
      <encoder>
          <pattern>${CONSOLE_LOG_PATTERN}</pattern>
          <charset>utf8</charset>
      </encoder>
  </appender>

  <root level="INFO">
      <appender-ref ref="STDOUT"/>
  </root>
</configuration>

So it definitely reads the file but seems to be unable to instantiate the ch.qos.logback.core.ConsoleAppender class. What should I do in this case?

[sdeleuze]

You probably miss the org.codehaus.janino:janino dependency, I will refine the documentation to clarify it is required. With that I validated it works as expected.

[13940344135]

You probably miss the org.codehaus.janino:janino dependency, I will refine the documentation to clarify it is required. With that I validated it works as expected.

@sdeleuze
After adding org.codehaus.janino:janino:3.1.6 dependency, Error: Main entry point class 'example.staveware.stvwebstore.Application' not found. will happen when compile, please help.

[sdeleuze]

Hi, likely unrelated, I recommend starting a project from start.spring.io to be sure it is correct or check our logger sample.