Switch from Python DevContainer feature to OS-provided (#41)

* Switch from Python DevContainer feature to OS-provided

The DevContainer feature "python" always re-builds Python from source. This is a big issue for the build performance of the container, especially for cross-builds for arm64. Hence, we switch  to use the OS-provided Python. Note that this implies a change in patch version (from "3.12.11" to "3.12.3"), which should not be an issue.

* fix: install fixed git-lfs version

* minor cleanup

* fix: check if builder already exists

Author: opajonk

scripts/create_builder.sh

@@ -1,4 +1,8 @@
 #!/usr/bin/env bash
 set -euxo pipefail
 
-docker buildx create --name multiarch --driver docker-container --use
+if ! docker buildx inspect multiarch &>/dev/null; then
+  docker buildx create --name multiarch --driver docker-container --use
+else
+  docker buildx use multiarch
+fi

src/s-core-devcontainer/.devcontainer/devcontainer-lock.json

@@ -20,11 +20,6 @@
       "resolved": "ghcr.io/devcontainers/features/git-lfs@sha256:71c2b371cf12ab7fcec47cf17369c6f59156100dad9abf9e4c593049d789de72",
       "integrity": "sha256:71c2b371cf12ab7fcec47cf17369c6f59156100dad9abf9e4c593049d789de72"
     },
-    "ghcr.io/devcontainers/features/python": {
-      "version": "1.7.1",
-      "resolved": "ghcr.io/devcontainers/features/python@sha256:cf9b6d879790a594b459845b207c5e1762a0c8f954bb8033ff396e497f9c301b",
-      "integrity": "sha256:cf9b6d879790a594b459845b207c5e1762a0c8f954bb8033ff396e497f9c301b"
-    },
     "ghcr.io/devcontainers/features/rust": {
       "version": "1.5.0",
       "resolved": "ghcr.io/devcontainers/features/rust@sha256:0c55e65f2e3df736e478f26ee4d5ed41bae6b54dac1318c443e31444c8ed283c",

src/s-core-devcontainer/.devcontainer/devcontainer.json

@@ -10,7 +10,7 @@
             "ppa": "true"
         },
         "ghcr.io/devcontainers/features/git-lfs": {
-            // Installs the latest version from the Distribution
+            "version": "3.7.0",
             "autoPull": "false" // do not automatically pull LFS files when creating the container
         },
         "ghcr.io/devcontainers/features/common-utils": {
@@ -26,9 +26,6 @@
             // In case we want this, the feature needs to be replaced with a custom installation script.
             "version": "20"
         },
-        "ghcr.io/devcontainers/features/python": {
-            "version": "3.12.11"
-        },
         "ghcr.io/devcontainers/features/rust": {
             "version": "1.83.0",
             "components": [
@@ -50,7 +47,6 @@
         "ghcr.io/devcontainers/features/common-utils",
         "ghcr.io/devcontainers-community/features/llvm",
         "ghcr.io/devcontainers/features/rust",
-        "ghcr.io/devcontainers/features/python",
         "./s-core-local"
     ],
     "remoteUser": "vscode",

src/s-core-devcontainer/.devcontainer/s-core-local/install.sh

@@ -30,6 +30,12 @@ apt-get install -y graphviz="${graphviz_version}*"
 # Protobuf compiler, via APT (needed by FEO)
 apt-get install -y protobuf-compiler="${protobuf_compiler_version}*"
 
+# Python, via APT
+apt-get install -y python${python_version} python3-pip python3-venv
+# The following packages correspond to the list of packages installed by the
+# devcontainer feature "python" (cf. https://github.com/devcontainers/features/tree/main/src/python )
+apt-get install -y flake8 python3-autopep8 black python3-yapf mypy pydocstyle pycodestyle bandit pipenv virtualenv python3-pytest pylint
+
 # Bazelisk, directly from GitHub
 # Using the existing devcontainer feature is not optimal:
 # - it does not check the SHA256 checksum of the downloaded file

src/s-core-devcontainer/.devcontainer/s-core-local/tests/test_default.sh

@@ -13,6 +13,16 @@ check "validate graphviz has the correct version" bash -c "dpkg -s graphviz | gr
 # Other build-related tools
 check "validate protoc is working and has the correct version" bash -c "protoc --version | grep 'libprotoc ${protobuf_compiler_version}'"
 
+# Python-related tools (a selected sub-set; others may be added later)
+check "validate python3 is working and has the correct version" bash -c "python3 --version | grep '${python_version}'"
+check "validate pip3 is working and has the correct version" bash -c "pip3 --version | grep '${python_version}'"
+check "validate black is working and has the correct version" bash -c "black --version | grep '${python_version}'"
+# cannot grep versions as they do not match the Python version
+check "validate virtualenv is working" bash -c "virtualenv --version"
+check "validate flake8 is working" bash -c "flake8 --version"
+check "validate pytest is working" bash -c "pytest --version"
+check "validate pylint is working" bash -c "pylint --version"
+
 # Bazel-related tools
 check "validate bazelisk is working and has the correct version" bash -c "bazelisk version | grep '${bazelisk_version}'"
 check "validate bazel is working and has the correct version" bash -c "bazel version | grep '${bazel_version}'"

src/s-core-devcontainer/.devcontainer/s-core-local/versions.yaml

@@ -10,6 +10,9 @@ qemu_system_arm:
 sshpass:
   version: 1.09
 
+python:
+  version: "3.12"
+
 bazel:
   # https://github.com/bazelbuild/bazel/releases -- latest version as of 2025-09-24
   version: 8.4.1

src/s-core-devcontainer/test-project/test.sh

@@ -7,8 +7,7 @@ source "${SCRIPT_DIR}/../../../scripts/test-utils.sh" vscode
 
 # Common tooling
 check "validate git is working and has the correct version" bash -c "git --version | grep '2.49.0'"
-check "validate git-lfs is working and has the correct version" bash -c "git lfs version | grep '3.7.0' "
-check "validate python3 is working and has the correct version" bash -c "python3 --version | grep '3.12.11'"
+check "validate git-lfs is working and has the correct version" bash -c "git lfs version | grep '3.7.0'"
 
 # C++ tooling
 check "validate clangd is working and has the correct version" bash -c "clangd --version | grep '20.1.8'"