file_fetcher.go

type fileFetcher struct {
       data []byte
       file string
}

func NewFileFetcher(filename string) (S3Fetcher, error) {
       // read contents of file
       jsonBuff, err := ioutil.ReadFile(filename)
       if err != nil {
               return nil, err
       }
       // Create a S3Fetcher object and inject the jsonBuff inside a reader regardless of what S3 object is requested
       ret := &fileFetcher{
               data: jsonBuff,
               file: filename,
       }
       return ret, nil
}