Create the easeprobe.pid file & Accept HUP Signal to Rotate Log

[haoel]

two major features:

• pid file: we can configure the PID file in settings, and if configured to empty "", it would be disabled.

  • If the file already exists, EaseProbe would overwrite it.
  • If the file cannot be written, EaseProbe would exit with an error.
  • If want disables the PID file, you can configure the pid file to "".

• HUP signal handling: rotate the access log of the application log once receive the HUP signal.

   log:
     file: /path/to/log/file
     self_rotate: true # default: true

  If self_rotate is true, EaseProbe would rotate the log automatically, and the following options are available:

    size: 10 # max size of log file. default: 10M
    age: 7 # max age days of log file. default: 7 days
    backups: 5 # max backup log files. default: 5
    compress: true # compress. default: true

  If self_rotate is false, EaseProbe would not rotate the log, and the log file would be rotated by the 3rd-party tool. e.g. logrotate.

[haoel]

@proditis @zhao-kun I've updated this PR's description (at the beginning), please help to review it. Thanks in advance!

[proditis]

Everything looks good to me (up to the point I can understand).

Great work everyone 👏

[proditis]

💯

[proditis]

👍