Making packages

A ply package is an inert image: files under its own prefix plus a tiny manifest describing its PATH/LD_LIBRARY_PATH contributions. No install scripts — ever. That makes packages easy to mint.

#apk2pkg — convert Alpine packages

The apk2pkg tool converts any Alpine package (plus its dependency closure) into a single self-contained ply package:

apk2pkg ffmpeg --alpine 3.20 -o ./out
# → out/ffmpeg-6.1.1-linux-x64.img

It downloads the apk and everything it needs, vendors the closure into one keg (/opt/ffmpeg-6.1.1/), resolves Alpine's virtual provides (so things like ICU data land where binaries expect them), and emits a canonical, content-addressed image.

Names and versions are normalized to ply's grammar: g++ → gpp, _ → -, versions padded to x.y.z.

This is the machinery behind the official registry — mainstream Alpine packages, pre-converted and served from a CDN, so most of the time you don't run apk2pkg at all.

#ply craft — author interactively

For anything that isn't an Alpine package, craft turns a shell session into a package. The overlay upper layer is the layer:

ply craft new --base [email protected] mytools    # opens a shell on the base
# …inside: install things, copy files, configure…
ply craft changes mytools                   # what did the session add?
ply craft commit mytools --version 0.1.0    # → mytools-0.1.0-linux-x64.img

Sessions persist between shells (ply craft shell), can be listed (ply craft ls), discarded (ply craft rm), and — because a committed package is just an image — resumed anywhere from the artifact itself (ply craft edit). The result is a normal, inert, content-addressed package.

#Plain directories

The lowest-tech path: an app-layer dependency can be a static binary you vendor straight into your app directory before ply build. What npm's ffmpeg-static does today needs zero ply support.

#Publishing

However a package is made, publishing is copying a file — see Registries & publishing. Upload to GitHub Releases, any bucket, or a directory, add an index.json if you want range resolution, done.