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Comment by purkka | Hacker News Reader

>You have containers that have worked for years that all of a sudden error out saying "Python 2 is no longer supported,"

Isn't this precisely the problem containers are trying to solve? You can update your system, get rid of unsupported software, and still keep the older version of Debian within your container that depends on an unsupported version of Python.

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That's the dream of containers. Arguably this is the "reality" of Nix. But the reality of containers is that if a layer gets invalidated, you need to refetch packages that are lower down. If the Python 2 versions (or Python 2 itself) is removed, then you can't "just" surgically make the change you want in the container without affecting the rest of the system (this is a major failing of Docker, but the world we live in). Now, you can start digging around in the container image and trying to do "layer surgery" yourself by editing the tars, but I would also consider that a less than ideal outcome of these changes.

Nix is also now intentionally breaking any packages that use Python 2, in my experience, so unless you're using a specific, older Nix channel, you're unlikely to have much success with anything that needs Python 2.

How would Python 2 end up removed from a container image?

If someone builds a container that is designed like this:

  FROM debian

  RUN do-x
  RUN install python2

and then someone changes do-x, if I understand, the layers below it get invalidated and all of a sudden install python2 fails. This is very bad design but very easy to replicate.

Okay, but surely my poorly written dockerfile that grabs the wrong images and runs broken code is not Debian's or python's problem?

Older versions of debian that still support python2 will theoritically be around forever, and any codebase that absolutely needs them should always work.

(though I contend that, given that we've had 15 YEARS of warning that this was coming, such instances should be vanishingly rare and not under active development)

> … "given that we've had 15 YEARS of warning that this was coming" …

This right here is the part that I'm still having troubles wrapping my brain around. People still stressing about Python 2 "going away" (it's gone folks; accept it) despite the fact that there's been well beyond a decade of advance warning, and Python 2 having been officially EOL ages ago now.

People won't move until heavens fall down on them.

And than they will start complaining that it's other peoples fault that they didn't move.

I have noticed pip warnings in the container build logs about python2 being unsupported- perhaps there is some "treat warnings as errors" flag set in some builds. Perhaps some builds use untagged base OS containers- building those after python2 is removed will fail.

Also, at some point old OS package repositories may be deleted (or bitrot out of neglect)- at that point building containers that depend on python2 will fail. You'll be able to use images built previously, but not everyone is backing up custom images in some remote docker registry.

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