1. 描述

项目启动，Logback配置出错（FileNamePattern格式和timeBasedFileNamingAndTriggeringPolicy没对应上）。

• 环境

IDE： 2021.3
spring boot： 2.5.6 (spring-boot-starter-logging: 2.5.6 --- logback-classic: 1.2.6)

• 配置1：

	<FileNamePattern>${LOG_HOME}/info${LOG_NAME}_%d{yyyy-MM-dd}.part_%i.log</FileNamePattern>
    <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.DefaultTimeBasedFileNamingAndTriggeringPolicy" />

• 配置2：

	<FileNamePattern>${LOG_HOME}/info${LOG_NAME}_%d{yyyy-MM-dd}.log</FileNamePattern>
    <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
        <maxFileSize>10KB</maxFileSize>
    </timeBasedFileNamingAndTriggeringPolicy>

2. 问题

• 问题1：

Logging system failed to initialize using configuration from 'null'
java.lang.IllegalStateException: Logback configuration error detected: 
ERROR in c.q.l.core.rolling.DefaultTimeBasedFileNamingAndTriggeringPolicy - Filename pattern [/var/demo_log_logback_%d{yyyy-MM-dd}.part_%i.log] contains an integer token converter, i.e. %i, INCOMPATIBLE with this configuration. Remove it.
	at org.springframework.boot.logging.logback.LogbackLoggingSystem.loadConfiguration(LogbackLoggingSystem.java:179)
	at org.springframework.boot.logging.AbstractLoggingSystem.initializeWithConventions(AbstractLoggingSystem.java:80)

• 问题2：

Logging system failed to initialize using configuration from 'null'
java.lang.IllegalStateException: Logback configuration error detected: 
ERROR in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@56cdfb3b - Missing integer token, that is %i, in FileNamePattern [/var/demo_log_logback_%d{yyyy-MM-dd}.log]
ERROR in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP@56cdfb3b - See also http://logback.qos.ch/codes.html#sat_missing_integer_token
	at org.springframework.boot.logging.logback.LogbackLoggingSystem.loadConfiguration(LogbackLoggingSystem.java:179)
	at org.springframework.boot.logging.AbstractLoggingSystem.initializeWithConventions(AbstractLoggingSystem.java:80)

• 原因：

DefaultTimeBasedFileNamingAndTriggeringPolicy ： 不支持 %i
SizeAndTimeBasedFNATP： 需要 %i

3. 解决

• 调整 FileNamePattern的参数值格式。

4. 资料

logback 手册appender标签：https://logback.qos.ch/manual/appenders.html