Change cpython version

Questions / Help
1

Is there any way to change the python version used by the buildpacks? I saw on the paketo buildpack documentation a possible way, but it does seem to work in my fly.toml file. It is posted below:

[build]
builder = “paketobuildpacks/builder:base”
[[build.env]]
name = “BP_CPYTHON_VERSION”
value = “3.9.14”

2

@LowellVCM this worked for me

[build]
  builder = "paketobuildpacks/builder:base"
  buildpack = ["paketo-buildpacks/python"]
[build.args]
  BP_CPYTHON_VERSION = "3.9.16"
3

How do you specify which builder version to use? I want to use Python 3.12.0 which is supported here: Releases · paketo-buildpacks/cpython · GitHub

However when I use flyctl deploy I’m seeing it’s using:
paketo-buildpacks/cpython 1.8.11
which only supports up to Python 3.11.4 and therefore I get the error:
failed to satisfy "python" dependency version constraint "3.11.5": no compatible versions on "io.buildpacks.stacks.bionic" stack. Supported versions are: [3.7.16, 3.7.16, 3.7.17, 3.7.17, 3.8.16, 3.8.16, 3.8.17, 3.8.17, 3.9.16, 3.9.16, 3.9.17, 3.9.17, 3.10.11, 3.10.11, 3.10.12, 3.10.12, 3.11.3, 3.11.3, 3.11.4, 3.11.4]

Is there a way to use v1.11.0 of the buildpack so that I can use up to Python 3.12.0?

4

using this buildpack technique doesn’t work for setting up flask app. it will display this error message

reparing paths
Running build command
Paketo Buildpack for CPython 1.8.11
  Resolving CPython version
    Candidate version sources (in priority order):
      BP_CPYTHON_VERSION -> "3.12.0"
                         -> ""
      <unknown>          -> ""

failed to satisfy "python" dependency version constraint "3.12.0": no compatible versions on "io.buildpacks.stacks.bionic" stack. Supported versions are: [3.7.16, 3.7.16, 3.7.17, 3.7.17, 3.8.16, 3.8.16, 3.8.17, 3.8.17, 3.9.16, 3.9.16, 3.9.17, 3.9.17, 3.10.11, 3.10.11, 3.10.12, 3.10.12, 3.11.3, 3.11.3, 3.11.4, 3.11.4]
ERROR: failed to build: exit status 1

does anyone know how to configure fly’s default buildpack’s CPython version to 3.12?