logback-spring. is unable to read property value from application.yml

Question

My logback-spring.xml reads fine from application.properties but not from application.yml. In my project, we have been asked to only use the YAML format as this format is being used in other microservices within the same project, so I cannot add propertes file. please help me why my application.yml is not read in logback.xml

I have tried variety of ways and searched similar questions on stackoverflow but no question has correct answer**. please dont mark this as duplicate**.

 <?xml version="1.0" encoding="UTF-8"?>
    <configuration>
        <include resource="org/springframework/boot/logging/logback/defaults.xml"/>
        <include resource="org/springframework/boot/logging/logback/base.xml"/>
        <include resource="org/springframework/boot/logging/logback/console-appender.xml"/>
        <property resource ="application.yml"/>
        <property name="LOGS" value="./logs" />
        <appender name="Console"
            class="ch.qos.logback.core.ConsoleAppender">
            <layout class="ch.qos.logback.classic.PatternLayout">
                <Pattern>
                    %black(%d{ISO8601}) %highlight(%-5level) [%blue(%t)] %yellow(%C{1.}): %msg%n%throwable
                </Pattern>
            </layout>
        </appender>
    
        <appender name="RollingFile"
            class="ch.qos.logback.core.rolling.RollingFileAppender">
            <file>${LOGS}/${spring.application.name}.log</file>
            <encoder
                class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
                <Pattern>%d %p %C{1.} [%t] %m%n</Pattern>
            </encoder>
    
            <rollingPolicy
                class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
                <!-- rollover daily and when the file reaches 10 MegaBytes -->
                <fileNamePattern>${LOGS}/archived/spring-boot-logger-%d{yyyy-MM-dd}.%i.log
                </fileNamePattern>
                <timeBasedFileNamingAndTriggeringPolicy
                    class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                    <maxFileSize>10MB</maxFileSize>
                </timeBasedFileNamingAndTriggeringPolicy>
            </rollingPolicy>
        </appender>
        
        <!-- LOG everything at INFO level -->
        <root level="info">
            <appender-ref ref="RollingFile" />
            <appender-ref ref="Console" />
        </root>
    
        <!-- LOG "com.baeldung*" at TRACE level -->
        <logger name="com.ms" level="trace" additivity="false">
            <appender-ref ref="RollingFile" />
            <appender-ref ref="Console" />
        </logger>
    
    </configuration>

Above is my logback-spring.xml. Please refer my application.yml below:-

spring:
  application:
    name: Logbacking-service

Answer 1

You can use below in your logback file as explained in the docs here

<springProperty name = "appname" source= "spring.application.name"/>

and then use this elsewhere

<file>${LOGS}/${appname}.log</file>

I tested the exact code you used and it was indeed giving issue so the above solution should work as it work for me as well. Earlier with your code the log file name that was getting generated was "appname_IS_UNDEFINED.log", and post the above change the name was "Logbacking-service.log".

If you enable trace logging level in your logback for "org.springframework.core.env.PropertySourcesPropertyResolver" you will see the location of application.yml from where it reads the properties. This will help you understand from where the spring boot is trying to find configuration. Something like below

Searching for key 'spring.profiles.active' in PropertySource 'applicationConfig: [classpath:/application.yml]