如何获取目录范围内文件的绝对路径?

Implemented a log parser on GO, at the moment the program takes a path parameter in this format example /var/log/2019/2019-05/2019-05-27/, only parses the current folder and returns the full file paths, I would like to know and how to implement the parser paths to files in the form such as --datastart /var/log/2019/2019-05/2019-05-01/ --dataend/ var/log/2019/2019-05/2019-05-31/, in order to parse a certain range of dates, which are divided into folders.

Sample directory tree

2019
|
-...
-2019-04
       |
       -2019-04-01
       |
       -....
       -2019-03-30
-2019-05
       |
       -2019-05-01
       |
       ...
       |
       -2019-05-31
-...

My function for getting directories files:

func WalkFile(done <- chan struct{},root string)(<-chan string,<-chan error){

  paths := make(chan string)
  errc  := make(chan error,1)

  go func() {

    defer close(paths)
    errc <- filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
      if err != nil{
        return err
      }
      if !info.Mode().IsRegular(){
        return nil

      }

      select {
      case paths <- path:
      case <-done:
        return nil


      }
      return nil
    })

  }()

  return paths,errc
}