lackey

The primary purpose that lackey is to manage a lower-quality version of your music library. This comes in handy when you want to compress your collection of FLACs to something you can put on your phone (for example).

The lackey program is distributed under the MIT License.

Installation

If you have Go installed, installing lackey is easy:

go get -u github.com/cassava/lackey
cd $GOPATH/src/github.com/cassava/lackey
go install ./cmd/...

Usage

At the moment, lackey's functionality is quite basic. It comes with several commands and flags that you can use. There are four commands:

• sync – synchronizes from your high-quality music library to a lower-quality mirror
• stats – reads a library and prints information about it (this may not be particularly useful for you, but it is for me as the dev)
• version – shows the version and compilation date of lackey
• help – shows the help for lackey and the other commands

Let's say your music library is at ~/music, and you would like a mirror at ~/music2go. Then we would use lackey like this:

lackey sync --library=~/music --delete-before ~/music2go

This will by default use the following options (as shown by lackey help sync):

• it will follow symlinks (--follow-symlinks=true)
• it will unconditionally convert non-MP3 music with the LAME encoder with a quality setting of 4 (--quality=4). See the LAME encoder on what the quality setting means. Lower is better.
• it will convert existing MP3s if they have a bitrate higher than 256kbps, and copy them otherwise (--threshold=256)
• it will copy all data files that are not music
• it will delete all unexpected files in the destination (like rsync does it, essentially)
• it will use the number of cores as the number of workers to use (--concurrent=4)

Note that reading in the library can take a few minutes (I hope to improve this in the future); it's insignificant compared to converting and copying files, but you probably don't want to do this when there's nothing to do.

With these settings, I can reduce a 110GB library to about 30GB. If you want it to take up even less space, you can increase the quality setting and reduce the threshold at which it is converted. If you want to configure even more, let me know and I'll see what I can do.

With Docker

There's a Docker image now that lets you easily automate this task in a job.

Build the image first:

docker build -t lackey:latest .

Run the image like so:

docker run --rm -it \
  -v $(pwd)/hifi:/mnt/hifi:ro \
  -v $(pwd)/lofi:/mnt/lofi \
  lackey:latest \
  lackey -L /mnt/hifi sync -s --cover-target folder.jpg -m -d --bitrate 192k --opus --threshold 192 /mnt/lofi

Of course, adjust the parameters as required. This worked pretty well for me. Note that I mounted my source directory as read-only (:ro), which protects it from mistakes in lackey as well as mistakes I might make in the call. I highly highly recommend you protect your source material in one way or another.

If you want to run the image as a service, you can do that too:

docker run --rm \
  -v $(pwd)/hifi:/mnt/hifi:ro \
  -v $(pwd)/lofi:/mnt/lofi \
  -p 8080:8080 \
  lackey:latest

This will spawn a service that runs continuously in the background and lets you interactively spawn a job by visiting the port in a browser.