add initial container builds of gentoo derived python versions

Signed-off-by: Brian Harring <ferringb@gmail.com>

Author: ferringb

.github/workflows/images.yml

@@ -0,0 +1,41 @@
+name: Build Python Images
+
+on:
+    schedule:
+        - cron: '0 0 * * 0'
+    workflow_dispatch:
+
+jobs:
+    build:
+        runs-on: ubuntu-latest
+        permissions:
+            contents: read
+            packages: write
+        strategy:
+            matrix:
+                PYTHON_VERSION: ['3.12', '3.13', '3.14']
+                PYTHON_UMASK: [false]
+                include:
+                    - PYTHON_VERSION: 3.15
+                      PYTHON_UNMASK: true
+            fail-fast: false
+        steps:
+            - name: Checkout code
+              uses: actions/checkout@v5
+            - name: Log in to GHCR
+              uses: docker/login-action@v3
+              with:
+                  registry: ghcr.io
+                  username: ${{ github.actor }}
+                  password: ${{ secrets.GITHUB_TOKEN }}
+
+            - name: Build image
+              run: |
+                  docker build \
+                    --build-arg PYTHON_VERSION=${{ matrix.PYTHON_VERSION }} \
+                    --build-arg PYTHON_UMASK=${{ matrix.PYTHON_UNMASK && '1' || '' }} \
+                    --tag ghcr.io/${{ github.repository }}/python:${{ matrix.PYTHON_VERSION }} \
+                    -f ./python-images/base.dockerfile ./python-images/
+            - name: Push image
+              run: |
+                  docker push ghcr.io/${{ github.repository }}/python:${{ matrix.PYTHON_VERSION }}

python-images/base.dockerfile

@@ -0,0 +1,14 @@
+FROM docker.io/gentoo/stage3
+ARG PYTHON_VERSION
+ARG PYTHON_UNMASK
+# use webrsync for speed reasons, and since we don't care about "latest from today"
+RUN [ -n "${PYTHON_VERSION}" ] || { echo "--build-arg PYTHON_VERSION must be passed"; exit 1; }
+RUN \
+  atom="<dev-lang/python-${PYTHON_VERSION}.99:${PYTHON_VERSION}" && \
+  mkdir -p /etc/portage/package.{accept_keywords,unmask} && \
+  echo "${atom} $([ -n "${PYTHON_UNMASK}" ] && echo '**')" >> /etc/portage/package.accept_keywords/python && \
+  [ -z "$PYTHON_UNMASK" ] || echo "${atom}" > /etc/portage/package.unmask/python
+RUN \
+  emerge-webrsync && \
+  emerge -u dev-lang/python && \
+  rm -rf /var/cache/distfiles /var/db/repos/gentoo