Registry Explorer

This beautiful tool allows you to explore the contents of a registry interactively.

You can even drill down into layers to explore an image's filesystem.

Enter a public image, e.g. "ubuntu:latest":

Enter a public repository, e.g. "ubuntu":

Interesting examples

• cgr.dev/chainguard/static:latest-glibc
• gcr.io/distroless/static:latest
• ghcr.io/homebrew/core/crane
• registry.k8s.io
• registry.k8s.io/bom/bom:sha256-499bdf4cc0498bbfb2395f8bbaf3b7e9e407cca605aecc46b2ef1b390a0bc4c4.sig
• docker/dockerfile:1.5.1
• pengfeizhou/test-oci:sha256-04eaff953b0066d7e4ea2e822eb5c31be0742fca494561336f0912fabc246760
• tianon/true:oci
• ghcr.io/stargz-containers/node:13.13.0-esgz

FAQ

How does this work?

This service lives on Cloud Run and uses google/go-containerregistry for registry interactions.

Isn't this expensive for the registry?

Not really! The first time a layer is accessed, I download and index it. Browsing the filesystem just uses that index, and opening a file uses Range requests to load small chunks of the layer as needed.

That can't be true, gzip doesn't support random access!

That's not a question.

Okay then, how does random access work if the layers are gzipped tarballs?

Great question! See here.

Tl;dr, you can seek to an arbitrary position in a gzip stream if you know the 32KiB of uncompressed data that comes just before it, so by storing ~1% of the uncompressed layer size, I can jump ahead to predetermined locations and start reading from there rather than reading the entire layer.

Thanks @aidansteele!

Is this open source?

Yes! See here.