flowsurgeon 0.3.2

FlowSurgeon — framework-agnostic profiling middleware for Python (WSGI & ASGI).

FlowSurgeon

Framework-agnostic profiling middleware for Python — works with Flask (WSGI) and FastAPI / Starlette (ASGI) out of the box.

FlowSurgeon injects a lightweight debug panel into every HTML response and stores request history in a local SQLite database, giving you timing, headers, and status codes without touching your application code.

Features

• Zero required dependencies — pure stdlib
• WSGI middleware (FlowSurgeonWSGI) for Flask, Django, and any WSGI app
• ASGI middleware (FlowSurgeonASGI) for FastAPI, Starlette, and any ASGI app
• FlowSurgeon() factory — auto-detects WSGI vs ASGI
• Inline debug panel injected into HTML responses
• Built-in history UI at /__flowsurgeon__/
• SQLite persistence with auto-pruning
• Sensitive header redaction (Authorization, Cookie)
• FLOWSURGEON_ENABLED environment variable kill switch

Installation

pip install flowsurgeon

Quick start

FastAPI (ASGI)

from fastapi import FastAPI
from flowsurgeon import FlowSurgeon, Config

_app = FastAPI()
app = FlowSurgeon(_app, config=Config(enabled=True))

@_app.get("/")
async def index():
    return {"hello": "world"}

Run with uvicorn:

uvicorn myapp:app

Flask (WSGI)

from flask import Flask
from flowsurgeon import FlowSurgeon, Config

flask_app = Flask(__name__)
flask_app.wsgi_app = FlowSurgeon(
    flask_app.wsgi_app,
    config=Config(enabled=True),
)

Configuration

from flowsurgeon import Config

Config(
    enabled=True,                          # default: False (or FLOWSURGEON_ENABLED=1)
    allowed_hosts=["127.0.0.1", "::1"],    # hosts that see the panel
    db_path="flowsurgeon.db",              # SQLite file path
    max_stored_requests=1000,              # auto-prune threshold
    debug_route="/__flowsurgeon__",        # history UI prefix
    strip_sensitive_headers=["authorization", "cookie", "set-cookie"],
)

Debug UI

Route	Description
/__flowsurgeon__/	Paginated request history
/__flowsurgeon__/{id}	Full detail for one request

Roadmap

• v0.3.0 — SQL query tracking (SQLAlchemy, DB-API 2.0)
• v0.4.0 — CPU and memory profiling panel
• v0.5.0 — Log capture and headers panel
• v0.6.0 — Improved history/search UI

License

MIT