I am thinking to make the following tool, but wanted to get opinions before I embark on this journey.

The tool builds container images.

The images are optionally distroless: meaning, they do not include an entire distro. They only include the application(s) you specify and its dependencies.

What else does the tool give you?

  • the build tool uses a package manager to do dependency resolution, so you don’t have to manually resolve them like many docker files do. (NOTE: The package manager is not installed on the container image. It is only used by the build tool)
  • uses gentoo’s portage to build the software from source (if not previously cached). This is helpful when you’re using versions of software that aren’t built against each other in the repos you download from
  • allows specifying compile flag customizations per package.
  • makes use of gentoo’s existing library of package build or install recipes, so that you only have to write them for uncommon apps rather than in every docker file.

I find it crazy that so many dockerfiles are doing their own dependency resolution when we already have package managers.

What do you think? Is this tool useful or am I missing a reason why it wouldn’t be?

  • matcha_addictOPEnglish
    31·
    4 months ago4 months ago

    The package manager would not be part of the container image. The package manager is only used to build it. The container image will only include the packages the user specifies.

    combining portions of images as multi-stage builds

    That’s something I am making use of for this, actually :)

    What you’re describing not only already exists…

    Can you please give an example of a tool that can build a container image by being given only a list of packages it needs to have?

    My tool would be as simple as doing something like this:

    build-container --packages nodejs-20.1.1, yarn-4.2.2, some-app-i-made-1.0.0

    And I would have a container that only has nodejs binary, yarn, and my own app. no package manager or any utils.

    • just_another_person
      10·
      4 months ago

      Yes. In your example, the base image is nodejs, which includes yarn. Then you copy your app into it with a COPY command and set the entrypoint to execute. Dead simple.

      • matcha_addictOPEnglish
        10·
        4 months ago

        the base image is nodejs

        Which has its own dockerfile. My proposed tool would allow using other images as base too, but that is not the problem it is solving.

        copy your app

        Well you’d have to have it compiled or built if that is required in your case. With my system, the build recipe would be a gentoo ebuild (shell-script-like) that you would just reference.

        The example I gave is pretty simple, you’re right. Say in another case, you list the following packages:

        nodejs, nginx, vpn-app(wireguard), some-system-monitoring-app, my-app

        You could start with a nodejs base or an nginx base, and then write the steps to install the other. You’d also have to make sure to get all the deps if they have them.

        You’re unlikely to find a ready image that has all what you want. But with my method, you can compose different ones however you like, rather than having to find an image that matches your exact use case.

        • just_another_person
          10·
          4 months ago

          Again, all you’re describing is just scripting tools that already exist together.

          My question is “WHY?”. You’ve not been able to describe a problem that needs a solution. I’m seeing in these other comments that you’re just deflecting that question, so do you know what you’re trying to solve here?

          • matcha_addictOPEnglish
            20·
            4 months ago

            Please demonstrate how the example I gave above can be done with common scripting tools, such it would mimic the declarative experience I described. I don’t think it is possible as you claim.

            Can you please point to where I deflected any questions? I looked and could not find any instances of such.

            I actually answered the question “why”, please refer to previous comments. It is also answered in the main post. But I will rephrase and summarize again here:

            • when creating a container image that requires certain applications installed, most dockerfiles explicitly install the dependencies of said applications as well. With my tool, you only declare the package you need, and it will resolve dependencies automatically and install them for you.
            • the above would work with distroless containers too, as the package manager used is outside of the produced container.