Logback with spring-boot: use ${user.home} does not work - spring-boot

Question

I can't figure out why logback does not take into account the variable defined in the corresponding application-{env}.yml file.
Here is the content of logback-spring.xml file:
<configuration>
<include resource="org/springframework/boot/logging/logback/base.xml" />
<springProperty scope="context" name="LOG_FILE" source="logging.file"
defaultValue="localhost"/>
<property name="LOG_FILE" value="${LOG_FILE}"/>
<appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${LOG_FILE}.log</file>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<!-- daily rollover -->
<fileNamePattern>${LOG_FILE}.%d{yyyy-MM-dd}.gz</fileNamePattern>
<!-- keep 30 days' worth of history capped at 3GB total size -->
<maxHistory>30</maxHistory>
<totalSizeCap>3GB</totalSizeCap>
</rollingPolicy>
<encoder>
<pattern>%-4relative [%thread] %-5level %logger{35} - %msg%n</pattern>
</encoder>
</appender>
<logger name="com.example.demospringweb" level="INFO">
<appender-ref ref="FILE" />
</logger>
<springProfile name="default">
<root level="debug">
<appender-ref ref="CONSOLE"/>
</root>
<logger name="com.demospringweb" level="DEBUG" additivity="false">
<appender-ref ref="CONSOLE" />
</logger>>
</springProfile>
<springProfile name="qa, prod">
<logger name="com.demospringweb" level="WARN" additivity="false">
<appender-ref ref="FILE" />
</logger>
</springProfile>
</configuration>
And here is the content of the application.yml file:
greeting: Default greeting
password: default-pass
logging:
path: ${user.home}
file: ${logging.path}/demo_localhost
max-history: 30
level:
com:
example: debug
org:
hibernate: ERROR
springframework:
web: DEBUG
When I start the spring-boot app, it does not create a required log file.
UPDATE
I removed completely spring-logback.xml and kept profile-specific properties in corresponding application.yml files.
Here is the application.yml file and it never writes (creates) a log file:
greeting: Default greeting
password: default-pass
spring:
application:
name: demo-spring
logging:
file: demo-dev
pattern:
file: "%d{dd-MM-yyyy HH:mm:ss.SSS} %logger.%M - %msg%n"
console: "%d{dd-MM-yyyy HH:mm:ss.SSS} %magenta([%thread]) %highlight(%-5level) %logger.%M - %msg%n"
level:
root: debug
org:
hibernate: ERROR
springframework:
web: DEBUG
What am I missing?

Answer 1

Finally, I figured out how to achieve that.
Remove logback-spring.xml or logback.xml file if there is any. In this case, Spring boot will use the default values defined by Logback if they are not overridden in your application.yml (or application.properties) file.
Create application.yml and application-prod.yml. file (you can add as many as you want, depending on how many environments you are going to have.
Here is the content of application.yml file used for development:
spring:
application:
name: demo-spring
greeting: Development greeting
password: dev-pass
logging:
pattern:
console: "%d{dd-MM-yyyy HH:mm:ss.SSS} %magenta([%thread]) %highlight(%-5level) %logger.%M - %msg%n"
level:
root: debug
org:
hibernate: ERROR
springframework:
web: debug
com:
example:
demospringweb: info
In this case, the output will be printed to the console only using the provided pattern. The root log level is set to debug but the package com.example.demospringweb is set to info(you can use either UPPERCASE or lower cased versions of log levels).
Create a profile-specific application-prod.yml file that will be used when the app is started with the prod activated:
spring:
application:
name: demo-spring
greeting: Production greeting
password: prod-pass
logging:
path: ${user.home}/logs
file: ${logging.path}/prod.log
total-size-cap: 100MB
max-history: 10
max-file-size: 5MB
pattern:
console: off
file: "%d{dd-MM-yyyy HH:mm:ss.SSS} [%thread] %-5level %logger{36}.%M - %msg%n"
rolling-file-name: ${logging.path}/plage_%d{dd-MM-yyyy}_%i.log
level:
root: info
org:
hibernate: ERROR
springframework:
web: warn
com:
example:
demospringweb: info
As you see, when starting the app with spring-boot:run -Dspring-boot.run.profiles=prod Spring Boot will use the values defined in application-prod.yml file:
write the logs to the file prod.log created in the user $HOME/logs directory. We also defined a rolling policy to keep 10 days history of max 5Mb by file max. The total size of all the log files is set to 100 Mb. Once it is achieved, the oldest file will be removed.
We also defined different log levels (root and by package).
To check how the logging varies depending on the active profile, take a look at the GreetingController:
package com.example.demospringweb.controllers;
import com.example.demospringweb.models.Greeting;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.concurrent.atomic.AtomicLong;
#RestController
public class GreetingsController {
private static final Logger LOGGER = LoggerFactory.getLogger(GreetingsController.class);
private final AtomicLong counter = new AtomicLong();
#Value("${greeting}")
private String greeting;
#Value("${password}")
private String password;
#GetMapping("/greeting")
public Greeting greeting() {
LOGGER.debug("This is a debug message");
LOGGER.info("This is an info message");
LOGGER.warn("This is a warn message");
LOGGER.error("This is an error message");
String message = greeting + "/pwd: " + password;
return new Greeting(counter.incrementAndGet(), message);
}
}
Voilà.