in-toto VS apko

The things you mentioned are not solved by a typical "SBOM" but e.g. CycloneDX has extra fields to record provenance and pedigree and things like in-toto (https://in-toto.io/) or SLSA (https://slsa.dev/) also aim to work in this field.

I've spent the last six months in this field and people will tell you that this or that is an industry best practice or "a standard" but in my experience none of that is true. Everyone is still trying to figure out how best to protect the software supply chain security and things are still very much in flux.

in-toto is an open source project that focuses on the attestation part of software supply chain security. You use it to define a “layout” for a project, i.e., how the different components should fit together. A project ships this definition with its code, and then another user of that software can compare what they have with the attached definition to see if it matches the structure and contents they expect. If it doesn’t, then this could point to external tampering or other issues.

But it's not all doom and gloom because the industry is evolving. Companies like Google are formulating tools like scorecard to heuristically reduce risk by encouraging you to rely on trustable dependencies only. There's also more complex tools like in-toto that actually look at the integrity of your supply chain (don't ask me how this one works, I just know that people like it).

apko allows us to build OCI container images from .apk packages.

We have built something very similar to what you are describing: https://github.com/chainguard-dev/apko

apko

Chainguard also appears to have several open source projects.The most popular one is apko, used for building OCI images from APK packages.

Once those are done, I just need to build aws-cli package, put those APK files in a final image with Chainguard's apko.

This is one of my absolute favorite topics. Pardon me while I rant and self-promote :D

Dockerfiles are great for flexibility, and have been a critical contributor to the adoption of Docker containers. It's very easy to take a base image, add a thing to it, and publish your version.

Unfortunately Dockerfiles are also full of gotchas and opaque cargo-culted best practices to avoid them. Being an open-ended execution environment, it's basically impossible to tell even during the build what's being added to the image, which has downstream implications for anybody trying to get an SBOM from the image for example.

Instead, I contribute to a number of tools to build and manage images without Dockerfiles. Each of them are less featureful than Dockerfiles, but being more constrained in what they can do, you can get a lot more visibility into what they're doing, since they're not able to do "whatever the user wants".

1. https://github.com/google/go-containerregistry is a Go module to interact with images in the registry and in tarballs and layouts, in the local docker daemon. You can append layers, squash layers, modify metadata, etc.

2. crane is a CLI that uses the above (in the same repo) to make many of the same modifications from the commandline. `crane append` for instance adds a layer containing some contents to an image, entirely in the registry, without even pulling the base image.

3. ko (https://ko.build) is a tool to build Go applications into images without Dockerfiles or Docker at all. It runs `go build`, appends that binary on top of a base image, and pushes it directly to the registry. It generates an SBOM declaring what Go modules went into the app it put into the image, since that's all it can do.

4. apko (https://apko.dev) is a tool to assemble an image from pre-built apks, without Docker. It's capable of producing "distroless" images easily with config in YAML. It generates an SBOM declaring exactly what apks it put in the image, since that's all it can do.

Bazel's rules_docker is another contender in the space, and GCP's distroless images use it to place Debian .debs into an image. Apko is its spiritual successor, and uses YAML instead of Bazel's own config language, which makes it a lot easier to adopt and use (IMO), with all of the same benefits.

I'm excited to see more folks realizing that Dockerfiles aren't always necessary, and can sometimes make your life harder. I'm extra excited to see more tools and tutorials digging into the details of how container images work, and preaching the gospel that they can be built and modified using existing tooling and relatively simple libraries. Excellent article!

Depends exactly what you're trying to create it for. I advocate for doing it during the build process rather than as a step after.

We open sourced a few tools that do it automatically for containers:

https://github.com/chainguard-dev/apko

https://github.com/chainguard-dev/melange

apko takes apk packages and builds them into OCI images (aka Docker images). Sounds quite simple, because it is: