How to pass a Spring property to Log4j in a Spring Boot application

DemoSpringAppApplication.java

package com.vlkan.demo.spring;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import javax.annotation.PostConstruct;

@SpringBootApplication
public class DemoSpringAppApplication {

    private static final Logger LOGGER = LoggerFactory.getLogger(DemoSpringAppApplication.class);

    @Autowired
    public DemoSpringAppApplication(@Value("${spring.profiles.active}") String profile) {
        System.setProperty("spring-profile", profile);
    }

    @PostConstruct
    public void startUp() {
        LOGGER.warn("started");
    }

    public static void main(String[] args) {
        SpringApplication.run(DemoSpringAppApplication.class, args);
    }

}

log4j2-layout.json

{
  "a_profile": "${sys:a_profile}",
  "b_profile": "${b_profile}",
  "mdc": "${json:mdc}",
  "exception": {
    "exception_class": "${json:exception:className}",
    "exception_message": "${json:exception:message}",
    "stacktrace": "${json:exception:stackTrace:text}"
  },
  "line_number": "${json:source:lineNumber}",
  "class": "${json:source:className}",
  "@version": 1,
  "source_host": "${hostName}",
  "message": "${json:message}",
  "thread_name": "${json:thread:name}",
  "@timestamp": "${json:timestamp}",
  "level": "${json:level}",
  "file": "${json:source:fileName}",
  "method": "${json:source:methodName}",
  "logger_name": "${json:logger:name}"
}

log4j2.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="warn">
    <Properties>
        <property name="a_profile">${sys:spring.profiles.active}</property>
        <property name="b_profile">${bundle:application:spring.profiles.active}</property>
    </Properties>
    <Appenders>
        <Console name="CONSOLE" target="SYSTEM_OUT">
            <LogstashLayout dateTimeFormatPattern="yyyy-MM-dd'T'HH:mm:ss.SSSZZZ"
                            eventTemplateUri="classpath:log4j2-layout.json"
                            prettyPrintEnabled="true"
                            stackTraceEnabled="true"/>
        </Console>
    </Appenders>
    <Loggers>
        <Root level="info">
            <AppenderRef ref="CONSOLE"/>
        </Root>
    </Loggers>
</Configuration>

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/>
    </parent>

    <groupId>com.vlkan.demo.spring</groupId>
    <artifactId>demo-spring-app</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <properties>
        <java.version>11</java.version>
    </properties>

    <dependencies>

        <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>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-log4j2</artifactId>
        </dependency>

        <dependency>
            <groupId>com.vlkan.log4j2</groupId>
            <artifactId>log4j2-logstash-layout</artifactId>
            <version>0.16</version>
        </dependency>

    </dependencies>

</project>