how do I change log level in runtime without restarting spring boot application

Question

I have deployed springboot application in PCF . I want to log the message based on the environment variable .What should I do so that the run time log level change will work without restarting the application?

Answer 1

Changing the log level in Spring Boot 1.5+ can be done with a http-endpoint

Add

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

and than you can use

curl -X "POST" "http://localhost:8080/loggers/de.springbootbuch" \      -H "Content-Type: application/json; charset=utf-8" \      -d $'{   "configuredLevel": "WARN" }'   

Where everything beyond /loggers/ is the name of the logger.

If you running this in PCF it get's even better: This is directly supported from their backend.

Answer 2

For Spring Boot 2.1.5+:

First, you need the actuator Plugin:

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

Second, you need to expose the endpoint like Dennis said in his comment (loggers is disabled by default):

management.endpoints.web.exposure.include=health,info,loggers 

Finally, you can use the Rest Endpoints to get Information about the loggers and set the logging levels.

curl -X "GET" "http://localhost:8080/actuator/loggers" 

To set the Root logging Level you can use

curl -X "POST" "http://localhost:8080/actuator/loggers/ROOT" -H "Content-Type: application/json; charset=utf-8"   -d $'{ "configuredLevel": "INFO" }'