Spring Boot: How can I set the logging level with application.properties?

Question

This is very simple question, but I cannot find information.
(Maybe my knowledge about Java frameworks is severely lacking)

How can I set the logging level with application.properties?
And logging file location, etc?

Austenite

For the record, another option is to set the log level as environment variable, for example via the heroku dashboard. In Settings -> Config Vars set logging.level.com.yourpackage to the desired level (INFO, ERROR, DEBUG). – Delorisdelorme

@Delorisdelorme I like that idea. Can you please explain how to read the value of environment variables and have it set under application.properties, such that it's different from development to testing (or production) environment? Or just redirect us to a link or something. I would appreciate that. – Topographer

Hi @KareemJeiroudi - no need to read the value manually; you can use the pattern logging.level.my.package.name=DEBUG in properties file or define the variable in heroku with key 'logging.level.my.package.name' and value 'DEBUG' and that should set your logging level for the defined package. – Delorisdelorme

Answer 1

Update: Starting with Spring Boot v1.2.0.RELEASE, the settings in application.properties or application.yml do apply. See the Log Levels section of the reference guide.

logging.level.org.springframework.web: DEBUG
logging.level.org.hibernate: ERROR

For earlier versions of Spring Boot you cannot. You simply have to use the normal configuration for your logging framework (log4j, logback) for that. Add the appropriate config file (log4j.xml or logback.xml) to the src/main/resources directory and configure to your liking.

You can enable debug logging by specifying --debug when starting the application from the command-line.

Spring Boot provides also a nice starting point for logback to configure some defaults, coloring etc. the base.xml file which you can simply include in your logback.xml file. (This is also recommended from the default logback.xml in Spring Boot.

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

Emblaze

Normally anything that you can do on the command line works in an external config file. So debug=true would do it I think. That flag is a little bit special because the logging has to be initialized very early, but I think that would work. – Haehaecceity

BTW the preferred logging system is logback, and that's what you get by default from the starter poms. So logback.xml is the most common tool to configure logging in a fine grained way. The --debug flag just switches on some selected Spring logging channels. – Haehaecceity

Another tip, spring boot includes a nice base.xml. Which is a nice starting point. (See my extended answer). – Emblaze

@M.Deinum Thank you again for your great tip! Now I can change the log level for my own code. – Austenite

If I use this base.xml, I get lots of nice logging, but I can't turn it off. I've tried adding <logger name="org.springframework.boot" level="WARN"/> after the include, but it doesn't work. If I remove the <include>, everything is quiet. But then I don't know when my app has finished starting. – Tripartite

I figured it out. By setting spring.debug=false in application.properties, setting the values in logback.xml actually works. – Tripartite

It seems we can, now. As for Spring v4.1.3.RELEASE (with Spring Boot v1.2.0.RELEASE), the settings in application.properties or application.yml do apply, as answered by Richard (modulo the : or = issue---the colon seems to work for me). – Medellin

Also for unmentioned other packages you can write like "logging.level.root=info" – Check

Answer 2

You can do that using your application.properties.

logging.level.=ERROR -> Sets the root logging level to error
...
logging.level.=DEBUG -> Sets the root logging level to DEBUG

logging.file=${java.io.tmpdir}/myapp.log -> Sets the absolute log file path to TMPDIR/myapp.log

A sane default set of application.properties regarding logging using profiles would be: application.properties:

spring.application.name=<your app name here>
logging.level.=ERROR
logging.file=${java.io.tmpdir}/${spring.application.name}.log

application-dev.properties:

logging.level.=DEBUG
logging.file=

When you develop inside your favourite IDE you just add a -Dspring.profiles.active=dev as VM argument to the run/debug configuration of your app.

This will give you error only logging in production and debug logging during development WITHOUT writing the output to a log file. This will improve the performance during development ( and save SSD drives some hours of operation ;) ).

Anoxia

The '=' sign for assignment did not work. The assignment was done with a ':' as separator. logging.level.:DEBUG – Nerte

Strange, I have this setup working in an example project. The ' '(space), '=' and ':' signs treated equally as separator except for cases where separators are used in keys. Are you sure your key didn't contain any white spaces? – Anoxia

Can confirm that ":" works but "=" is ignored, Edit: Spoke to soon, there was a space between "=" and the level. everything works now. – Donothingism

This don't work in my test with spring-boot 1.4.0: logging.level.=DEBUG will cause application fail to start, and getting error: java.lang.ClassCircularityError: java/util/logging/LogRecord – Pettigrew

Seems to me logging.level. is just a convenience syntactic shortcut for logging.level.root, which could be prefered as (1) less prone to be confused with a typo, (2) potentially more explicit, and (3) working with the = assignment sign, which provides more overall consistency to the configuration file. – Chromaticity

Answer 3

The proper way to set the root logging level is using the property logging.level.root. See documentation, which has been updated since this question was originally asked.

Example:

logging.level.root=WARN

Diuresis

Answer 4

If you are on Spring Boot then you can directly add following properties in application.properties file to set logging level, customize logging pattern and to store logs in the external file.

These are different logging levels and its order from minimum << maximum.

OFF << FATAL << ERROR << WARN << INFO << DEBUG << TRACE << ALL

# To set logs level as per your need.
logging.level.org.springframework = debug
logging.level.tech.hardik = trace

# To store logs to external file
# Here use strictly forward "/" slash for both Windows, Linux or any other os, otherwise, its won't work.      
logging.file=D:/spring_app_log_file.log

# To customize logging pattern.
logging.pattern.file= "%d{yyyy-MM-dd HH:mm:ss} - %msg%n"

Please pass through this link to customize your log more vividly.

https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-logging.html

Transcendentalism

I don't know why but logging.level.tech.hardik = trace this is not working in my case when i put logging.level.roo=trace it's working – Cryoscopy

@ArvindKumar here tech.hardik is package name, please change it to package name as per your app. – Transcendentalism

Answer 5

According to the documentation you can have different logging levels based on java packages.

 logging.level.com.mypackage.myproject=WARN
 logging.level.org.springframework=DEBUG
 logging.level.root=INFO 

This would mean that

• For your custom package com.mypackage.myproject WARN logging level would be applied
• For spring framework package org.springframework DEBUG logging level would be applied
• For every other package INFO logging level would be applied

You can also group together different java packages and instruct the system to use the same logging level for all packages of the group in a single line.

In the previous example you could do

 logging.level.root=INFO 
 logging.level.org.springframework=DEBUG
 
 logging.group.myCustomGroup = com.mypackage.myproject, com.otherpackage.otherproject, com.newpackage.newproject
 logging.level.myCustomGroup=WARN

This would mean that the packages

• com.mypackage.myproject
• com.otherpackage.otherproject
• com.newpackage.newproject

would all have logging level WARN applied

Traver

Answer 6

Suppose your application has package name as com.company.myproject. Then you can set the logging level for classes inside your project as given below in application.properties files

logging.level.com.company.myproject = DEBUG

logging.level.org.springframework.web = DEBUG and logging.level.org.hibernate = DEBUG will set logging level for classes of Spring framework web and Hibernate only.

For setting the logging file location use

logging.file = /home/ubuntu/myproject.log

Dedra

Answer 7

Making sure Dave Syer tip gets some love, because adding debug=true to application.properties will indeed enable debug logging.

Odisodium

There is an important difference to other ways like logging.level.root=debug which will enable debug loggin for all components. The debug=trueenables debug mode. "When the debug mode is enabled, a selection of core loggers (embedded container, Hibernate and Spring Boot) are configured to output more information. Enabling the debug mode does not configure your application to log all messages with DEBUG level." See docs.spring.io/spring-boot/docs/1.5.22.RELEASE/reference/html/… – Terrific

Answer 8

With Springboot 2 you can set the root logging Level with an Environment Variable like this:

logging.level.root=DEBUG

Or you can set specific logging for packages like this:

logging.level.my.package.name=TRACE

Vincent

for environment variables configuration, you'd rather use: LOGGING_LEVEL_ROOT=DEBUG , using the camel case syntax – Titanothere

Answer 9

logging:
  level:
    root: INFO
    com.mycompany.myapp: DEBUG

Insectivorous

Answer 10

In case you want to use a different logging framework, log4j for example, I found the easiest approach is to disable spring boots own logging and implement your own. That way I can configure every loglevel within one file, log4j.xml (in my case) that is.

To achieve this you simply have to add those lines to your pom.xml:

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

<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-log4j</artifactId>
</dependency>

You probably already have the first dependency and only need the other two. Please note, that this example only covers log4j.
That's all, now you're all set to configure logging for boot within your log4j config file!

Ebberta

This exclusion worked for me. My REST Api were not picked my log4j dependency and log4j.properties. – Pallette

they also have spring-boot-starter-log4j2 now – Norval

Answer 11

We can also turn on DEBUG log via command line like below:-

java -jar <jar file> --debug

Aimless

This answer deserves more love. It's effective and temporary, no need to edit a file. – Witch

It might be just what you want, but be aware that it enables debug mode. "When the debug mode is enabled, a selection of core loggers (embedded container, Hibernate and Spring Boot) are configured to output more information. Enabling the debug mode does not configure your application to log all messages with DEBUG level." See docs.spring.io/spring-boot/docs/1.5.22.RELEASE/reference/html/… – Terrific

Answer 12

You can try setting the log level to DEBUG it will show everything while starting the application

logging.level.root=DEBUG

Barela

Answer 13

Existing answers are greats. I just want to share with you a new spring boot feature allowing to group logs and set logging level on the whole group.

Exemple from the docs :

• Create a logging group

logging.group.tomcat=org.apache.catalina, org.apache.coyote, org.apache.tomcat

• Set the logging level for group

logging.level.tomcat=TRACE

It's nice feature which brings more flexibility.

Evangelineevangelism

Answer 14

For the records: the official documentation, as for Spring Boot v1.2.0.RELEASE and Spring v4.1.3.RELEASE:

If the only change you need to make to logging is to set the levels of various loggers then you can do that in application.properties using the "logging.level" prefix, e.g.

logging.level.org.springframework.web: DEBUG logging.level.org.hibernate: ERROR

You can also set the location of a file to log to (in addition to the console) using "logging.file".

To configure the more fine-grained settings of a logging system you need to use the native configuration format supported by the LoggingSystem in question. By default Spring Boot picks up the native configuration from its default location for the system (e.g. classpath:logback.xml for Logback), but you can set the location of the config file using the "logging.config" property.

Medellin

Answer 15

If you want to set more detail, please add a log config file name "logback.xml" or "logback-spring.xml".

in your application.properties file, input like this:

logging.config: classpath:logback-spring.xml

in the loback-spring.xml, input like this:

    <?xml version="1.0" encoding="UTF-8"?>
    <configuration>
        <include resource="org/springframework/boot/logging/logback/base.xml"/>

        <appender name="ROOT_APPENDER" class="ch.qos.logback.core.rolling.RollingFileAppender">

            <filter class="ch.qos.logback.classic.filter.LevelFilter">
                <level>INFO</level>
                <onMatch>ACCEPT</onMatch>
                <onMismatch>DENY</onMismatch>
            </filter>

            <file>sys.log</file>

            <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">


                <fileNamePattern>${LOG_DIR}/${SYSTEM_NAME}/system.%d{yyyy-MM-dd}.%i.log</fileNamePattern>

                <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                    <maxFileSize>500MB</maxFileSize>
                </timeBasedFileNamingAndTriggeringPolicy>
            </rollingPolicy>

            <encoder>
                <pattern>%-20(%d{yyy-MM-dd HH:mm:ss.SSS} [%X{requestId}]) %-5level - %logger{80} - %msg%n
                </pattern>
            </encoder>
        </appender>


        <appender name="BUSINESS_APPENDER" class="ch.qos.logback.core.rolling.RollingFileAppender">
            <filter class="ch.qos.logback.classic.filter.LevelFilter">
                <level>TRACE</level>
                <onMatch>ACCEPT</onMatch>
                <onMismatch>DENY</onMismatch>
            </filter>

            <file>business.log</file>

            <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">

                <fileNamePattern>${LOG_DIR}/${SYSTEM_NAME}/business.%d{yyyy-MM-dd}.%i.log</fileNamePattern>

                <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                    <maxFileSize>500MB</maxFileSize>
                </timeBasedFileNamingAndTriggeringPolicy>
            </rollingPolicy>

            <encoder>
                <pattern>%-20(%d{yyy-MM-dd HH:mm:ss.SSS} [%X{requestId}]) %-5level - %logger{80} - %msg%n
                </pattern>
            </encoder>
        </appender>


        <logger name="{project-package-name}" level="TRACE">
            <appender-ref ref="BUSINESS_APPENDER" />
        </logger>

        <root level="INFO">
            <appender-ref ref="ROOT_APPENDER" />
        </root>

    </configuration>

Stein

Answer 16

in spring boot project we can write logging.level.root=WARN but here problem is, we have to restart again even we added devtools dependency, in property file if we are modified any value will not autodetectable, for this limitation i came to know the solution i,e we can add actuator in pom.xml and pass the logger level as below shown in postman client in url bar http://localhost:8080/loggers/ROOT or http://localhost:8080/loggers/com.mycompany and in the body you can pass the json format like below

{
  "configuredLevel": "WARN"
}

Oogonium

Answer 17

In case of eclipse IDE and your project is maven, remember to clean and build the project to reflect the changes.

Emendate

Answer 18

In my current config I have it defined in application.yaml like that:

logging:
  level:
    ROOT: TRACE

I am using spring-boot:2.2.0.RELEASE. You can define any package which should have the TRACE level like that.

Coheman

This sets up at application level. OP wants trace only for the hibernate logs for which you would require a package level filter in log settings – Musclebound