SpringBoot with LogBack creating LOG_FILE_IS_UNDEFINED folder

Question

I am using SpringBoot with LogBack and I am trying to direct all log-statements of one specific package (here shown as \"com.example.somepackagename\") to a file. All other

Answer 1

I get similar issue, on application start following empty file might be generated:

• LOG_PATH_IS_UNDEFINED
• LOG_FILE_IS_UNDEFINED

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Reason

Logging related config in application.yml, is read after logback-spring.xml is parsed, thus can't read it.

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Possible solutions

I found 3 possible solutions, choose one that best fit your case:

1. Move logging config from application.yml to bootstrap.yml, this will need spring-cloud dependency to make it work.

   • This works because bootstrap.yml is read before logback-spring.xml.
   • If you are not using spring-cloud, this probably won't be your best choice, since the extra dependencies is unnecessary.

2. Define path & file in logback-spring.xml directly.
   e.g

    <configuration>
        <springProperty name="LOG_PATH" source="logging.path" defaultValue="logs/" />
        <springProperty name="LOG_FILE" source="logging.file" defaultValue="app.log" />
   

   In this case, might need to add "logback-spring.xml" to each sub project, if the log file names need to be different, and can't simply put the config file in a shared common dependency.

3. Just keep the config in application.yml, and ignore the generated empty files by setting .gitinore.
   e.g

    LOG_*_IS_UNDEFINED
   

   In this case, the logs are still written to the file specified by application.yml, though the empty file is generate.

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Tips

• The logback-spring.xml file mentioned above, might be logback.xml or some other name in your case.