Log4j log file not getting created at specified location springboot - spring

Question

I am trying to configure log4j2 in springboot.I have removed(excluded) the logback dependency already from pom.xml.I am using this xml under resource folder named log4j2.xml
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="DEBUG">
<Appenders>
<Console name="LogToConsole" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
</Console>
<File name="LogToFile" fileName="logs/app.log">
<PatternLayout>
<Pattern>%d %p %c{1.} [%t] %m%n</Pattern>
</PatternLayout>
</File>
</Appenders>
<Loggers>
<Logger name="com.ashish" level="debug" additivity="false">
<AppenderRef ref="LogToFile"/>
<AppenderRef ref="LogToConsole"/>
</Logger>
<Logger name="org.springframework.boot" level="error" additivity="false">
<AppenderRef ref="LogToConsole"/>
</Logger>
<Root level="error">
<AppenderRef ref="LogToFile"/>
<AppenderRef ref="LogToConsole"/>
</Root>
</Loggers>
</Configuration>
This is my controller class.
package com.ashish;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import java.util.Arrays;
import java.util.List;
#Controller
public class HelloController {
private static final Logger logger = LogManager.getLogger(HelloController.class);
private List<Integer> num = Arrays.asList(1, 2, 3, 4, 5);
#GetMapping("/")
public String main(Model model) {
if (logger.isDebugEnabled()) {
logger.debug("Hello from Log4j 2 - num : {}", num);
}
logger.debug("Hello from Log4j 2 - num : {}", () -> num);
model.addAttribute("tasks", num);
return "welcome";
}
private int getNum() {
return 100;
}
}
Am i missing anything here?I tried to set it using application.properties too using latest version of Log4j2.But still it's not getting created.When i run the application i can't see any log file getting dynamically created at the path specified in xml.

Answer 1

First, you have status="DEBUG" specified in your configuration. So you will see Log4j configure itself on the console (or wherever system.out is getting routed to). If you do not then you aren't really using Log4j.
If you do see the output then check the debug lines. I have a suspicion your log file is either not getting created due to a permissions problem or it isn't being written where you expect it.
Your configuration specifies a relative directory named "logs". Whatever directory is the working directory when the app is started should contain your logs directory. Frequently on Linux that will end up being "/". You almost certainly won't have permission to create a logs directory there so configuration will fail.

Answer 2

I can't comment on the content of the log4j2 config file itself, probably it will make sense to print on console first and make sure that its driven by log4j2 indeed.
However, I'll refer to the beginning of the question:
I am trying to configure log4j2 in springboot.I have removed(excluded) the logback dependency already from pom.xml
You don't present the pom.xml but in general in order to switch spring boot to work with log4j2 you should:
"Exclude" the default logging mechanism of spring boot:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-logging</artifactId>
</exclusion>
</exclusions>
</dependency>
Add a log4j2 starter that will in turn (transitively) add log4j2 dependency of the versions compatible with your spring boot version:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-log4j2</artifactId>
</dependency>
Quick googling has revealed this tutorial that contains all the steps including end-to-end example of such an integration.