Logback log framework learning and problems

1、 brief introduction

http://logback.qos.ch/, Chinese website http://www.logback.cn/
logback from log4j The founder of Ceki Gülcü Design , As log4j Successor to the framework ,logback Indeed, it is widely used . But from the updated records on the official website , Looks like 2019 Years later, the update speed was obviously slow , I don't know if it's time to go log4j The afterlife of .
Logback from logback core、logback classic and logback access Three modules .logback core It lays the foundation for the other two modules ,logback classic Realized SLF4J API, In this way, our application can switch between other logging frameworks , Such as log4j、java.util.logging (JUL).logback access And servlet Containers （ Such as tomcat or Jetty） Integrate , Provide HTTP To access logs .

2、 Core components

Logback Three core components ：Logger、Appender、Layout, The three work together , This allows developers to record messages by message type and level , And control the format of these messages and the location where they are recorded at run time .

3、 To configure

3.1 logback Profile path

The order in which the configuration files are found
（1）classpatch Find... In the path logback-test.xml
（2）classpatch Find... In the path logback.groovy
（3）classpatch Find... In the path logback.xml
（4） Custom profile path , Add... To the startup parameters logback.configurationFile Specify the profile path , Such as ：

There are other ways that have not been studied .

3.2 The configuration syntax

4、 Compatibility support

log4j Users can use the PropertiesTranslator take log4j The configuration is converted to logback To configure

5、 problem

5.1 The log file subscript exceeds 1000 Do not delete old files

When the log file subscript exceeds 1000 when , Don't delete files ,totalSizeCap It doesn't work ,bug link ：https://jira.qos.ch/browse/LOGBACK-1297
It's still in open state .
terms of settlement , take SizeAndTimeBasedRollingPolicy It is amended as follows FixedWindowRollingPolicy+SizeBasedTriggeringPolicy The way
Single file 10kb, Keep at most 5 File , Make the file subscript always in 1-5 Between , Not more than 1000：

5.2 SizeAndTimeBasedRollingPolicy Method does not precisely control size

Set a single file size 100kb, Total size 1MB when

It is found that the single file size is far larger than 100kb, Total size also exceeds 1MB

Decompress the log file and find , Single file size 1696KB

But the total size is maintained at 2.12 MB about , There has been no sustained growth