emqx4.3/rel/config/examples/log.file.conf.example

## Log to file

log.file {
    ## Enable file log handler
    enable = true

    ## Log level
    ## Type: debug | info | notice | warning | error | critical | alert | emergency
    level = warning

    ## Log formatter, text for free text, and json for more structured logging
    ## Type: text | json
    formatter = text

    ## Time offset for formatting the timestamp
    ## Type:
    ##   - system :: local system time
    ##   - utc :: UTC time
    ##   - +-[hh]:[mm]: user specified time offset, such as "-02:00" or "+00:00" Defaults to: system
    time_offset = system

    ## Maximum number of log files
    ## Type: Range from 1 to 128
    rotation_count = 10

    ## This parameter controls log file rotation
    ## Type:
    ##  - infinity :: the log file will grow indefinitely
    ##  - ByteSize :: the log file will be rotated once it reaches this value in bytes
    rotation_size = 50MB
}