CI: self-install Python on Windows; build Linux/arm64 in python+node container

First v0.1.0 run: Windows + Linux + arm64 failed (no Python on those runners;
the docker default image also lacks Python). macOS succeeded.
- windows: install Python 3.12 via the official installer in-job (idempotent).
- linux-amd64 / linux-arm64: run in nikolaik/python-nodejs:python3.12-nodejs20
  (has python+pip AND node for actions/checkout; multi-arch covers the Pi).
- macOS job unchanged (it worked).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016yT89n4zR4qbrySoSiEyZs

.gitea/workflows/release.yml

@@ -10,15 +10,21 @@ on:
 
 jobs:
   windows:
-    runs-on: windows-latest          # self-hosted Windows runner
+    runs-on: windows-latest          # self-hosted Windows runner (no Python preinstalled)
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-        with:
-          python-version: "3.12"
       - name: Build OBDash.exe (PyInstaller)
         shell: pwsh
         run: |
+          $ErrorActionPreference = "Stop"
+          if (-not (Get-Command python -ErrorAction SilentlyContinue)) {
+            Write-Host "Python not found; installing 3.12..."
+            $url = "https://www.python.org/ftp/python/3.12.7/python-3.12.7-amd64.exe"
+            Invoke-WebRequest -Uri $url -OutFile "$env:TEMP\py.exe"
+            Start-Process -Wait -FilePath "$env:TEMP\py.exe" -ArgumentList "/quiet","InstallAllUsers=1","PrependPath=1","Include_test=0"
+            $env:Path = "C:\Program Files\Python312;C:\Program Files\Python312\Scripts;$env:Path"
+          }
+          python --version
           python -m pip install --upgrade pip
           pip install -r requirements-gui.txt pyinstaller
           pyinstaller --noconfirm --onefile --windowed --name OBDash --add-data "profiles;profiles" run_gui.py
@@ -53,17 +59,14 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITEA_TOKEN }}
 
   linux-amd64:
-    runs-on: docker                  # Linux x86_64 runner (container)
+    runs-on: docker                  # Linux x86_64 runner
+    container: nikolaik/python-nodejs:python3.12-nodejs20  # has python+pip AND node (for checkout)
     steps:
       - uses: actions/checkout@v4
       - name: Build OBDash (PyInstaller)
         shell: bash
         run: |
-          # patchelf is needed for onefile; GL/EGL/xkb are runtime deps users need
-          (sudo apt-get update && sudo apt-get install -y python3-venv patchelf libgl1 libegl1 libxkbcommon0) \
-            || (apt-get update && apt-get install -y python3-venv patchelf libgl1 libegl1 libxkbcommon0) || true
-          python3 -m venv .build-venv
-          . .build-venv/bin/activate
+          apt-get update && apt-get install -y patchelf libgl1 libegl1 libxkbcommon0
           pip install --upgrade pip
           pip install -r requirements-gui.txt pyinstaller
           pyinstaller --noconfirm --onefile --name OBDash --add-data "profiles:profiles" run_gui.py
@@ -78,15 +81,13 @@ jobs:
 
   linux-arm64:
     runs-on: arm64                   # Raspberry Pi (aarch64) runner
+    container: nikolaik/python-nodejs:python3.12-nodejs20  # multi-arch: pulls arm64
     steps:
       - uses: actions/checkout@v4
       - name: Build OBDash (PyInstaller)
         shell: bash
         run: |
-          (sudo apt-get update && sudo apt-get install -y python3-venv patchelf libgl1 libegl1 libxkbcommon0) \
-            || (apt-get update && apt-get install -y python3-venv patchelf libgl1 libegl1 libxkbcommon0) || true
-          python3 -m venv .build-venv
-          . .build-venv/bin/activate
+          apt-get update && apt-get install -y patchelf libgl1 libegl1 libxkbcommon0
           pip install --upgrade pip
           pip install -r requirements-gui.txt pyinstaller
           pyinstaller --noconfirm --onefile --name OBDash --add-data "profiles:profiles" run_gui.py