Examples in the gif(in downloads folder) above run in real time(no persistent quering) on, approximately, 50 000 files on traditional HDD. Basically, speed of collecting data and building a query tree is on par with Walk function in GoLang.

Internally gokinate uses O(N) most prominent faceting tree. Which is, basically, a tree alignment based on most probable order of leafs/tags in a node.

If made right, this tree can allow constant time faceting/drilling down in faceted drilling applications. Index(tree) building is O(N) where N is a number of nodes. We discard here sorting as it is a very small amount(5-10 tags to sort per node).

go get github.com/MichaelLeachim/gokinate;
cd $GOPATH/src/github.com/MichaelLeachim/gokinate;
go build;
go install;
gokinate -p ~/Downloads/;

You can find config file here

cd $GOPATH/src/github.com/MichaelLeachim/gokinate;

Go to the program directory and change attrs.yaml file

You need go-bindata to be installed.

cd $GOPATH/src/github.com/MichaelLeachim/gokinate;
go-bindata "./attrs.yaml";
go build;
go install;

There are four workers available

-
  Worker: ext_worker
  Yes: image_file
  Ask: Is this an image?
  Items:
    - .tif
    - .tiff
    - .gif
    - .jpeg
    - .jpg
    - .nef
    - .png
    - .psd
    - .bmp

It works like that. You associate file extensions with Ask and answer function. Ask & answer are arbitrary fields. They can even, clash with each other.

-
  Worker: path_substring_worker
  Yes: downloaded
  Ask: Did you download it from the internet?
  Items: [Downloads,Download]

-
  Worker: size_range_worker
  Yes: small_file
  Ask: Is this file small(less than 100 megabytes)?
  Items:  [0,99]

-
  Worker: date_worker
  Yes: yesterday_file
  Ask: Did you get this file yesterday?
  Items:  [1,23]

Please, keep in mind, that complex extensions will substantially slow down walking on directory.

For example, I've removed id3 functionality from this program because it took very long time to extract mp3 meta-data. New extension must be placed in extensions.go file. In format:

func (el *Element_yaml) ext_worker(p AttrPath, i os.FileInfo) WorkerReturn {
	data := WorkerReturn{}
	for _, v := range el.Items {
		if v == p.Ext {
			data.Tag = Tag(el.Yes)
			data.TagAsk = el.Ask
			return data
		}
	}
	return data
}

And registered in dispatch tag function:

func Dispatch_Tag(el Element_yaml, p AttrPath, f os.FileInfo) WorkerReturn {
	result := WorkerReturn{}
	if el.Worker == "ext_worker" {
		result = el.ext_worker(p, f)
	}
	if el.Worker == "date_worker" {
		result = el.date_worker(p, f)
	}
	if el.Worker == "size_range" {
		result = el.size_range_worker(p, f)
	}
	if el.Worker == "path_substring_worker" {
		result = el.path_substring_worker(p, f)
	}
	return result
}