[spring boot] 기본 log 쓰지 않고, logback 사용할 수 있도록 추가하기

1. build.gradle (또는 pom.xml)에 logback 라이브러리 추가

compile("ch.qos.logback:logback-classic:1.1.2")
compile("ch.qos.logback:logback-core:1.1.2")
compile("org.slf4j:slf4j-api:1.7.6")

2. logback-spring.xml 정의

<?xml version="1.0" encoding="UTF-8"?>
<configuration>

    <include resource="org/springframework/boot/logging/logback/base.xml"/>

    <logger name="org.springframework.web" level="info"/>
    <logger name="com.kakao.story.gateway" level="debug" />
    <springProfile name="production">
        <logger name="com.kakao.story.gateway" level="info" />
    </springProfile>

3. application.yml 에 logging.config 추가
가장 중요함. 

logging:
  config: classpath:logback.xml