8 articles
RSSHow to fix httpx errors — RuntimeError event loop is closed, ReadTimeout exception, ConnectionResetError, async client not closing properly, HTTP/2 not enabled, SSL verify failed, and proxy not working.
How to fix Uvicorn errors — Address already in use port binding, reload not detecting changes, SSL certificate errors, worker class with gunicorn, WebSocket disconnect, graceful shutdown, and proxy headers behind nginx.
How to fix FastAPI BackgroundTasks — task not executing, dependency injection in tasks, error handling, Celery for heavy tasks, and lifespan-managed background workers.
How to fix Pydantic v2 validation errors — required fields, type coercion, model_validator, custom validators, extra fields config, and migrating from Pydantic v1.
How to fix FastAPI dependency injection errors — async dependencies, database sessions, sub-dependencies, dependency overrides in tests, and common DI mistakes.
How to fix Python asyncio event loop blocking — using run_in_executor for sync calls, asyncio.to_thread, avoiding blocking I/O in coroutines, and detecting event loop stalls.
How to fix Pydantic ValidationError in Python — missing required fields, wrong types, custom validators, handling optional fields, v1 vs v2 API differences, and debugging complex nested models.
How to fix FastAPI 422 Unprocessable Entity error caused by wrong request body format, missing fields, type mismatches, query parameter errors, and Pydantic validation.