feat: litestar application

lessons/232/python-litestar-app/.dockerignore

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+*.pyc
+*.pyo
+*.mo
+*.db
+*.css.map
+*.egg-info
+*.sql.gz
+.cache
+.project
+.idea
+.pydevproject
+.idea/workspace.xml
+.DS_Store
+.git/
+.sass-cache
+.vagrant/
+__pycache__
+dist
+docs
+env
+logs
+src/{{ project_name }}/settings/local.py
+src/node_modules
+web/media
+web/static/CACHE
+stats
+Dockerfile

lessons/232/python-litestar-app/.gitignore

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+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+cover/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+.pybuilder/
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+#   For a library or package, you might want to ignore these files since the code is
+#   intended to run in multiple environments; otherwise, check them in:
+# .python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# UV
+#   Similar to Pipfile.lock, it is generally recommended to include uv.lock in version control.
+#   This is especially recommended for binary packages to ensure reproducibility, and is more
+#   commonly ignored for libraries.
+#uv.lock
+
+# poetry
+#   Similar to Pipfile.lock, it is generally recommended to include poetry.lock in version control.
+#   This is especially recommended for binary packages to ensure reproducibility, and is more
+#   commonly ignored for libraries.
+#   https://python-poetry.org/docs/basic-usage/#commit-your-poetrylock-file-to-version-control
+#poetry.lock
+
+# pdm
+#   Similar to Pipfile.lock, it is generally recommended to include pdm.lock in version control.
+#pdm.lock
+#   pdm stores project-wide configurations in .pdm.toml, but it is recommended to not include it
+#   in version control.
+#   https://pdm.fming.dev/latest/usage/project/#working-with-version-control
+.pdm.toml
+.pdm-python
+.pdm-build/
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow and github.com/pdm-project/pdm
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# pytype static type analyzer
+.pytype/
+
+# Cython debug symbols
+cython_debug/
+
+# PyCharm
+#  JetBrains specific template is maintained in a separate JetBrains.gitignore that can
+#  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
+#  and can be added to the global gitignore or merged into this file.  For a more nuclear
+#  option (not recommended) you can uncomment the following to ignore the entire idea folder.
+#.idea/

lessons/232/python-litestar-app/Dockerfile

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+FROM python:3.12-slim-bookworm AS build
+
+ENV PYTHONDONTWRITEBYTECODE=1
+ENV PYTHONUNBUFFERED=1
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    build-essential \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+RUN pip install --upgrade pip
+COPY ./requirements.txt /app/requirements.txt
+RUN pip install --no-cache-dir -r /app/requirements.txt
+
+FROM python:3.12-slim-bookworm
+
+ENV PYTHONUNBUFFERED=1
+
+WORKDIR /app
+
+COPY --from=build /usr/local/lib/python3.12/site-packages /usr/local/lib/python3.12/site-packages
+COPY --from=build /usr/local/bin /usr/local/bin
+
+COPY . /app
+
+CMD ["gunicorn", "-w", "4", "-k", "uvicorn.workers.UvicornWorker", "--timeout", "60", "--graceful-timeout", "60", "--log-level", "error", "main:app", "--bind", "0.0.0.0:8000"]

lessons/232/python-litestar-app/db.py

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+from __future__ import annotations
+
+import logging
+import os
+from contextlib import asynccontextmanager
+from typing import AsyncGenerator
+
+import aiomcache
+import asyncpg
+
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+
+POSTGRES_URI = os.environ["POSTGRES_URI"]
+POSTGRES_POOL_SIZE = int(os.environ["POSTGRES_POOL_SIZE"])
+MEMCACHED_HOST = os.environ["MEMCACHED_HOST"]
+MEMCACHED_POOL_SIZE = int(os.environ["MEMCACHED_POOL_SIZE"])
+
+
+class Database:
+    __slots__ = ("_pool",)
+
+    def __init__(self, pool: asyncpg.Pool):
+        self._pool = pool
+
+    @staticmethod
+    async def from_postgres() -> Database:
+        """Create connection pool if it doesn't exist"""
+        try:
+            pool = await asyncpg.create_pool(
+                POSTGRES_URI,
+                min_size=10,
+                max_size=POSTGRES_POOL_SIZE,
+                max_inactive_connection_lifetime=300,
+            )
+            logger.info("Database pool created: %s", pool)
+
+            return Database(pool)
+        except asyncpg.exceptions.PostgresError as e:
+            logging.error(f"Error creating PostgreSQL connection pool: {e}")
+            raise ValueError("Failed to create PostgreSQL connection pool")
+        except Exception as e:
+            logging.error(f"Unexpected error while creating connection pool: {e}")
+            raise
+
+    @asynccontextmanager
+    async def get_connection(self) -> AsyncGenerator[asyncpg.Connection, None]:
+        """Get database connection from pool"""
+        async with self._pool.acquire() as connection:
+            logger.info("Connection acquired from pool")
+            yield connection
+            logger.info("Connection released back to pool")
+
+    async def close(self):
+        """Close the pool when shutting down"""
+        await self._pool.close()
+        logger.info("Database pool closed")
+
+
+class MemcachedClient:
+    __slots__ = ("_client",)
+
+    def __init__(self, client: aiomcache.Client):
+        self._client = client
+
+    @staticmethod
+    async def initialize() -> MemcachedClient:
+        """Initialize the Memcached client with connection pooling"""
+        try:
+            client = aiomcache.Client(
+                host=MEMCACHED_HOST, pool_size=MEMCACHED_POOL_SIZE
+            )
+            logger.info(f"Memcached client created: {client}")
+            return MemcachedClient(client)
+        except Exception:
+            logging.exception("Error creating Memcached client")
+            raise ValueError("Failed to create Memcached client")
+
+    async def close(self):
+        """Close the Memcached client"""
+        await self._client.close()
+        logger.info("Memcached client closed")
+
+    def get_client(self) -> aiomcache.Client:
+        """Get the Memcached client instance"""
+        return self._client