Feature - add uv support

README.md

@@ -10,6 +10,25 @@ This buildpack supports running Django and Flask apps.
 
 Official buildpack documentation can be found at [python buildpack docs](http://docs.cloudfoundry.org/buildpacks/python/index.html).
 
+### uv
+
+Apps managed with [uv](https://docs.astral.sh/uv/) are supported by pushing the `pyproject.toml` together with a `uv.lock`:
+
+* During staging the buildpack runs `uv sync --frozen` to install the locked packages into the buildpack's Python installation. Every package is verified against the hashes in `uv.lock`, and staging fails on a mismatch. Keep `uv.lock` up to date (`uv lock`) before pushing, as it is used as is.
+* Only the default dependencies are installed, dependency groups such as `dev` are skipped. If the project defines a `[build-system]`, the project itself is installed as well (non-editable).
+* The Python version is taken from `.python-version` (e.g. `3.12`, as written by `uv python pin`), unless a `runtime.txt` exists. uv never downloads its own Python; staging fails if the version does not satisfy `requires-python`.
+* Package indexes configured via `[[tool.uv.index]]` are used as configured. Credentials are not part of `uv.lock`; provide them as environment variables, e.g. `cf set-env <app> UV_INDEX_<NAME>_USERNAME ...` and `UV_INDEX_<NAME>_PASSWORD`. uv trusts the system certificate store, like pip does.
+* Django's `collectstatic`, as well as the installation of libffi and libmemcached, work as for pip apps.
+* If the app also contains a `requirements.txt`, the `uv.lock` and `.python-version` are ignored and pip is used.
+* For vendored (offline) installs, download the wheels for the target platform into the `vendor` directory. They are installed with `uv pip install --offline` and are verified against the hashes in `uv.lock` as well. Write the exported file outside the app, so that it does not take precedence over `uv.lock`:
+
+  ```bash
+  uv export --frozen --no-dev --no-hashes --no-emit-project -o /tmp/requirements.txt
+  pip download -r /tmp/requirements.txt -d vendor --only-binary=:all: --platform manylinux2014_x86_64 --python-version 3.12
+  ```
+
+  If the project defines a `[build-system]`, its build backend (e.g. `hatchling`) must be vendored as well.
+
 ## Adding new dependencies
 
 If you want to add a new dependency to the buildpack, please add it to the [config.yml](https://github.com/cloudfoundry/buildpacks-ci/blob/5a63d13df09f83d5dff7c71d0a12c3e2dc798d39/pipelines/dependency-builds/config.yml#L272) file. For example, if you want to add a new version of Python, add an entry like the following:

bin/detect

@@ -13,7 +13,7 @@ BUILD_DIR=$1
 BP=$(dirname $(dirname $0))
 
 # Exit early if app is clearly not Python.
-if [ ! -f $BUILD_DIR/requirements.txt ] && [ ! -f $BUILD_DIR/setup.py ] && [ ! -f $BUILD_DIR/environment.yml ] && [ ! -f $BUILD_DIR/Pipfile ]; then
+if [ ! -f $BUILD_DIR/requirements.txt ] && [ ! -f $BUILD_DIR/setup.py ] && [ ! -f $BUILD_DIR/environment.yml ] && [ ! -f $BUILD_DIR/Pipfile ] && { [ ! -f $BUILD_DIR/uv.lock ] || [ ! -f $BUILD_DIR/pyproject.toml ]; }; then
   exit 1
 fi
 

fixtures/uv/.gitignore

@@ -0,0 +1,2 @@
+*.pyc
+.venv

fixtures/uv/.python-version

@@ -0,0 +1 @@
+3.12

fixtures/uv/Procfile

@@ -0,0 +1 @@
+web: gunicorn server:app

fixtures/uv/pyproject.toml

@@ -0,0 +1,13 @@
+[project]
+name = "uv-app"
+version = "0.1.0"
+requires-python = ">=3.10"
+dependencies = [
+    "flask",
+    "gunicorn",
+]
+
+[dependency-groups]
+dev = [
+    "pytest",
+]

fixtures/uv/server.py

@@ -0,0 +1,18 @@
+import os
+
+from flask import Flask
+
+app = Flask(__name__)
+
+port = int(os.getenv('VCAP_APP_PORT', 8080))
+
+
+@app.route("/")
+def hello():
+    return "Hello, World!"
+
+
+app.debug = True
+
+if __name__ == '__main__':
+    app.run(host='0.0.0.0', port=port)

fixtures/uv_django/.gitignore

@@ -0,0 +1,3 @@
+*.pyc
+.venv
+static_root

fixtures/uv_django/Procfile

@@ -0,0 +1 @@
+web: waitress-serve --port=$PORT django_web_app.wsgi:application

fixtures/uv_django/django_web_app/asgi.py

@@ -0,0 +1,16 @@
+"""
+ASGI config for django_web_app project.
+
+It exposes the ASGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.1/howto/deployment/asgi/
+"""
+
+import os
+
+from django.core.asgi import get_asgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'django_web_app.settings')
+
+application = get_asgi_application()

fixtures/uv_django/django_web_app/settings.py

@@ -0,0 +1,119 @@
+"""
+Django settings for django_web_app project.
+
+Generated by 'django-admin startproject' using Django 4.1.5.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.1/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/4.1/ref/settings/
+"""
+
+from pathlib import Path
+
+# Build paths inside the project like this: BASE_DIR / 'subdir'.
+BASE_DIR = Path(__file__).resolve().parent.parent
+
+# Quick-start development settings - unsuitable for production
+# See https://docs.djangoproject.com/en/4.1/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = 'django-insecure-1&02gvsqhx5gvh44@)x%k03&79r*vkievzv0%yl*+vq5m)unm_'
+
+# SECURITY WARNING: don't run with debug turned on in production!
+DEBUG = True
+
+ALLOWED_HOSTS = ['*']
+
+# Application definition
+
+INSTALLED_APPS = [
+    'django.contrib.admin',
+    'django.contrib.auth',
+    'django.contrib.contenttypes',
+    'django.contrib.sessions',
+    'django.contrib.messages',
+    'django.contrib.staticfiles',
+]
+
+MIDDLEWARE = [
+    'django.middleware.security.SecurityMiddleware',
+    'whitenoise.middleware.WhiteNoiseMiddleware',
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.middleware.common.CommonMiddleware',
+    'django.middleware.csrf.CsrfViewMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+    'django.middleware.clickjacking.XFrameOptionsMiddleware',
+]
+
+ROOT_URLCONF = 'django_web_app.urls'
+
+TEMPLATES = [
+    {
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'DIRS': [],
+        'APP_DIRS': True,
+        'OPTIONS': {
+            'context_processors': [
+                'django.template.context_processors.debug',
+                'django.template.context_processors.request',
+                'django.contrib.auth.context_processors.auth',
+                'django.contrib.messages.context_processors.messages',
+            ],
+        },
+    },
+]
+
+WSGI_APPLICATION = 'django_web_app.wsgi.application'
+
+# Database
+# https://docs.djangoproject.com/en/4.1/ref/settings/#databases
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.sqlite3',
+        'NAME': BASE_DIR / 'db.sqlite3',
+    }
+}
+
+# Password validation
+# https://docs.djangoproject.com/en/4.1/ref/settings/#auth-password-validators
+
+AUTH_PASSWORD_VALIDATORS = [
+    {
+        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
+    },
+]
+
+# Internationalization
+# https://docs.djangoproject.com/en/4.1/topics/i18n/
+
+LANGUAGE_CODE = 'en-us'
+
+TIME_ZONE = 'UTC'
+
+USE_I18N = True
+
+USE_TZ = True
+
+# Static files (CSS, JavaScript, Images)
+# https://docs.djangoproject.com/en/4.1/howto/static-files/
+
+STATIC_URL = '/static/'
+STATIC_ROOT = 'static_root'
+
+# Default primary key field type
+# https://docs.djangoproject.com/en/4.1/ref/settings/#default-auto-field
+
+DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

fixtures/uv_django/django_web_app/urls.py

@@ -0,0 +1,21 @@
+"""django_web_app URL Configuration
+
+The `urlpatterns` list routes URLs to views. For more information please see:
+    https://docs.djangoproject.com/en/4.1/topics/http/urls/
+Examples:
+Function views
+    1. Add an import:  from my_app import views
+    2. Add a URL to urlpatterns:  path('', views.home, name='home')
+Class-based views
+    1. Add an import:  from other_app.views import Home
+    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
+Including another URLconf
+    1. Import the include() function: from django.urls import include, path
+    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
+"""
+from django.contrib import admin
+from django.urls import path
+
+urlpatterns = [
+    path('admin/', admin.site.urls),
+]

fixtures/uv_django/django_web_app/wsgi.py

@@ -0,0 +1,16 @@
+"""
+WSGI config for django_web_app project.
+
+It exposes the WSGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.1/howto/deployment/wsgi/
+"""
+
+import os
+
+from django.core.wsgi import get_wsgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'django_web_app.settings')
+
+application = get_wsgi_application()

fixtures/uv_django/manage.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
+import os
+import sys
+
+
+def main():
+    """Run administrative tasks."""
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'django_web_app.settings')
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == '__main__':
+    main()

fixtures/uv_django/pyproject.toml

@@ -0,0 +1,11 @@
+[project]
+name = "uv-django-app"
+version = "0.1.0"
+requires-python = ">=3.10"
+dependencies = [
+    "dj-database-url==1.2.0",
+    "Django==4.1.5",
+    "gunicorn==20.1.0",
+    "waitress==2.1.2",
+    "whitenoise==6.3.0",
+]