python.http_blocking_async

Performance High

Detects blocking HTTP calls in async code.

Why It Matters

Blocking HTTP in async:

• Event loop blocked — All other tasks stall
• Concurrency destroyed — Async benefits lost
• Timeout cascades — Other coroutines time out

Example

# ❌ Before (blocking call in async)
import requests

async def fetch_data():
    response = requests.get(url)  # Blocks event loop!
    return response.json()

# ✅ After (async HTTP client)
import httpx

async def fetch_data():
    async with httpx.AsyncClient() as client:
        response = await client.get(url)
        return response.json()

What Unfault Detects

• requests.get/post in async functions
• urllib calls in async context
• Sync HTTP clients in coroutines

Related Rules

• python.cpu_in_event_loop