How to change root logging level programmatically for logback

user_283200 0
Viewed 174268

I have the following logback.xml file:

<configuration debug="true"> 

<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender"> 
<encoder>
  <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
</encoder>
</appender>

<root level="debug">
  <appender-ref ref="STDOUT" />
</root>
</configuration>

Now, upon the occurrence of a specific event, I want to programmatically change the level of the root logger from debug to error. I can't use variable substitution, it is mandatory that I do this within the code.

How can it be done ? Thanks.

logback logging java
7 Answers

I think you can use MDC to change logging level programmatically. The code below is an example to change logging level on current thread. This approach does not create dependency to logback implementation (SLF4J API contains MDC).

<configuration>
  <turboFilter class="ch.qos.logback.classic.turbo.DynamicThresholdFilter">
    <Key>LOG_LEVEL</Key>
    <DefaultThreshold>DEBUG</DefaultThreshold>
    <MDCValueLevelPair>
      <value>TRACE</value>
      <level>TRACE</level>
    </MDCValueLevelPair>
    <MDCValueLevelPair>
      <value>DEBUG</value>
      <level>DEBUG</level>
    </MDCValueLevelPair>
    <MDCValueLevelPair>
      <value>INFO</value>
      <level>INFO</level>
    </MDCValueLevelPair>
    <MDCValueLevelPair>
      <value>WARN</value>
      <level>WARN</level>
    </MDCValueLevelPair>
    <MDCValueLevelPair>
      <value>ERROR</value>
      <level>ERROR</level>
    </MDCValueLevelPair>
  </turboFilter>
  ......
</configuration>

MDC.put("LOG_LEVEL", "INFO");
user_39026630

I seem to be having success doing

org.jboss.logmanager.Logger logger = org.jboss.logmanager.Logger.getLogger("");
logger.setLevel(java.util.logging.Level.ALL);

Then to get detailed logging from netty, the following has done it

org.slf4j.impl.SimpleLogger.setLevel(org.slf4j.impl.SimpleLogger.TRACE);
user_10477880

Here's a controller

@RestController
@RequestMapping("/loggers")
public class LoggerConfigController {

private final static org.slf4j.Logger LOGGER = LoggerFactory.getLogger(PetController.class);

@GetMapping()
public List<LoggerDto> getAllLoggers() throws CoreException {
    
    LoggerContext loggerContext = (LoggerContext) LoggerFactory.getILoggerFactory();
    
    List<Logger> loggers = loggerContext.getLoggerList();
    
    List<LoggerDto> loggerDtos = new ArrayList<>();
    
    for (Logger logger : loggers) {
        
        if (Objects.isNull(logger.getLevel())) {
            continue;
        }
        
        LoggerDto dto = new LoggerDto(logger.getName(), logger.getLevel().levelStr);
        loggerDtos.add(dto);
    }
    
    if (LOGGER.isDebugEnabled()) {
        LOGGER.debug("All loggers retrieved. Total of {} loggers found", loggerDtos.size());
    }
    
    return loggerDtos;
}

@PutMapping
public boolean updateLoggerLevel(
        @RequestParam String name, 
        @RequestParam String level
)throws CoreException {
    
    LoggerContext loggerContext = (LoggerContext) LoggerFactory.getILoggerFactory();
    
    Logger logger = loggerContext.getLogger(name);
    
    if (Objects.nonNull(logger) && StringUtils.isNotBlank(level)) {
        
        switch (level) {
            case "INFO":
                logger.setLevel(Level.INFO);
                LOGGER.info("Logger [{}] updated to [{}]", name, level);
                break;
                
            case "DEBUG":
                logger.setLevel(Level.DEBUG);
                LOGGER.info("Logger [{}] updated to [{}]", name, level);
                break;
                
            case "ALL":
                logger.setLevel(Level.ALL);
                LOGGER.info("Logger [{}] updated to [{}]", name, level);
                break;
                
            case "OFF":
            default: 
                logger.setLevel(Level.OFF);
                LOGGER.info("Logger [{}] updated to [{}]", name, level);
        }
    }
    
    return true;
}

}

user_34609270
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