Spring Boot Logging Levels Example

Learn to configure the logging levels for different packages in a Spring boot application using properties, YAML and XML configurations. We will see the different configurations are Logback and Log4j2 frameworks.

In the following examples, we can adjust the package names, class names and logging levels according to application-specific requirements. The logging levels can be one of TRACE, DEBUG, INFO, WARN, ERROR, or FATAL.

1. Configure Logging Levels using application.properties

The following is an example configuration for setting the logging levels using the /src/main/resources/application.properties file.

# Console appender to display logs in the console
logging.level.root=INFO

# Logging level configurations for specific packages
logging.level.com.howtodoinjava=DEBUG
logging.level.org.springframework=INFO

# Logging level configurations for specific class
logging.level.com.howtodoinjava.MyClass=WARN

2. Configure Logging Levels using application.yaml

The following is an example configuration for setting the logging levels using the /src/main/resources/application.yaml file.

# Console appender to display logs in the console
logging:
  level:
    root: INFO

# Logging level configurations for specific packages
  com.howtodoinjava: DEBUG
  org.springframework: INFO

# Logging level configurations for specific class
  com.howtodoinjava.MyClass: WARN

3. Configure Logging Levels using Logback

The following is an example configuration for setting the logging levels when customizing it in the logback configuration files.

3.1. logback.properties

# Console appender to display logs in the console
appender.console.type=Console
appender.console.name=CONSOLE
appender.console.encoder.pattern=%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%thread] %logger{36} - %msg%n

# Root logger level
rootLogger.level=INFO
rootLogger.appenderRef.console.ref=CONSOLE

# Logging level configurations for specific packages
logger.com.howtodoinjava.name=com.howtodoinjava
logger.com.howtodoinjava.level=DEBUG

logger.org.springframework.name=org.springframework
logger.org.springframework.level=INFO

logger.com.howtodoinjava.MyClass.name=com.howtodoinjava.MyClass
logger.com.howtodoinjava.MyClass.level=WARN

3.2. logback.yaml

configuration:
  appenders:
    console:
      name: CONSOLE
      target: SYSTEM_OUT
      encoder:
        pattern: "%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%thread] %logger{36} - %msg%n"
  root:
    level: INFO
    appender-ref:
      - ref: CONSOLE
  loggers:
    logger:
      - name: com.howtodoinjava
        level: DEBUG
      - name: org.springframework
        level: INFO
      - name: com.howtodoinjava.MyClass
        level: WARN

3.3. logback.xml

<configuration>

	<!-- Console appender to display logs in the console -->
	<appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
	    <encoder>
	        <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%thread] %logger{36} - %msg%n</pattern>
	    </encoder>
	</appender>

	<!-- Root logger level -->
	<root level="INFO">
	    <appender-ref ref="CONSOLE" />
	</root>

	<!-- Logging level configurations for specific packages -->
	<logger name="com.howtodoinjava" level="DEBUG" />
	<logger name="org.springframework" level="INFO" />

	<!-- Logging level configuration for specific class -->
	<logger name="com.howtodoinjava.MyClass" level="WARN" />

	<!-- Other logger configurations -->

</configuration>

4. Configuring Spring Boot Logging Levels for Log4j2

The following is an example configuration for setting the logging levels when customizing it in the Log4j2 configuration files.

4.1. log4j2.properties

# Console appender to display logs in the console
appender.console.type = Console
appender.console.name = CONSOLE
appender.console.layout.type = PatternLayout
appender.console.layout.pattern = %d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%thread] %logger{36} - %msg%n

# Root logger level
rootLogger.level = INFO
rootLogger.appenderRef.console.ref = CONSOLE

# Logging level configurations for specific packages
logger.com.howtodoinjava.name = com.howtodoinjava
logger.com.howtodoinjava.level = DEBUG

logger.org.springframework.name = org.springframework
logger.org.springframework.level = INFO

logger.com.howtodoinjava.MyClass.name = com.howtodoinjava.MyClass
logger.com.howtodoinjava.MyClass.level = WARN

4.2. log4j2.yaml

Configuration:
  Appenders:
    Console:
      name: CONSOLE
      target: SYSTEM_OUT
      PatternLayout:
        pattern: "%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%thread] %logger{36} - %msg%n"
  Loggers:
    Root:
      level: INFO
      AppenderRef:
        - ref: CONSOLE
    Logger:
      - name: com.howtodoinjava
        level: DEBUG
      - name: org.springframework
        level: INFO
      - name: com.howtodoinjava.MyClass
        level: WARN

4.3. log4j2.xml

<Configuration>
  <Appenders>
    <Console name="CONSOLE" target="SYSTEM_OUT">
      <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%thread] %logger{36} - %msg%n"/>
    </Console>
  </Appenders>
  <Loggers>
    <Root level="INFO">
      <AppenderRef ref="CONSOLE"/>
    </Root>
    <Logger name="com.howtodoinjava" level="DEBUG"/>
    <Logger name="org.springframework" level="INFO"/>
    <Logger name="com.howtodoinjava.MyClass" level="WARN"/>
  </Loggers>
</Configuration>

5. Conclusion

In this Spring boot tutorial, we learned to configure logging levels using both properties and YAML/XML configurations for Logback and Log4j2 frameworks. We learned to customize the logging levels for specified classes and packages as well.

Happy Learning !!