Unexpected Memory Leak When Using FastAPI with Background Tasks on Large File Uploads
I'm trying to configure I'm having trouble with I'm stuck on something that should probably be simple... I'm experiencing a important memory leak when using FastAPI to handle large file uploads while utilizing background tasks. My application allows users to upload files up to 1GB, and I'm leveraging FastAPI's background tasks to process these files asynchronously. However, I've noticed that memory usage keeps increasing and doesn't seem to be released after the processing is complete. Here’s a snippet of my FastAPI app that's handling the file upload: ```python from fastapi import FastAPI, UploadFile, File, BackgroundTasks import shutil app = FastAPI() async def process_file(file_path: str): # Simulating a background process that could consume a lot of memory with open(file_path, 'rb') as f: data = f.read() # Reading the whole file into memory # Process data here (e.g., data manipulation) @app.post("/upload/") async def upload_file(file: UploadFile = File(...), background_tasks: BackgroundTasks = BackgroundTasks()): file_location = f"./uploaded_files/{file.filename}" with open(file_location, "wb") as buffer: shutil.copyfileobj(file.file, buffer) background_tasks.add_task(process_file, file_location) return {"info": "File uploaded successfully"} ``` I’ve tried profiling the memory usage using `tracemalloc` and it shows that memory is not being freed after the background task completes. I also considered using `del` on large objects, but it does not seem to help. Has anyone encountered similar issues with FastAPI and can suggest ways to manage memory effectively, especially with large files? Is there a better pattern for handling file uploads and background processing that could help mitigate this question? I'm using FastAPI v0.95.0 and Python 3.10. I'm working on a CLI tool that needs to handle this. The stack includes Python and several other technologies.