[scan files]

• ignore hidden files ("." files)

[mimetype] file -p --mime -f [file-list-file] file -p -f [file-list-file]

[exiftool to extract image/video file meta] TODO

[lumberjack]

• fix go routine leaking

[doc fields] -------- basic meta

• id (content-hash), keyword
• size, long
• file-name, keyword
• file-ext, keyword
• mime-desc, text/keyword
• mime-type, keyword
• mime-subtype, keyword
• mime-encoding, keyword -------- extend meta
• timestamp
• year
• month
• day
• hour
• minute
• second
• location/country
• location/city