PyInstrument with FastAPI

main.py

from fastapi import FastAPI, Request
from fastapi.responses import HTMLResponse
from profiler import FastApiProfiler

app = FastAPI()

import .routes  # NOQA

PROFILING = True # Put this in Settings when you're ready

if PROFILING:
    @app.middleware("http")
    async def profile_request(request: Request, call_next):
        profile = FastApiProfiler()
        profile.start()
        response = await call_next(request)
        profile.stop()
        return HTMLResponse(profile.get_result_html())

profiler.py

import time

from pyinstrument import Profiler


class FastApiProfiler:
    def __init__(
        self,
        interval: float = 0.0001,
    ):
        self._profiler = Profiler(interval=interval, async_mode="enabled")

    def start(self) -> None:
        self._profiler.start()
        self._begin = time.perf_counter()

    def stop(self):
        self._profiler.stop()
        self._end = time.perf_counter()

    def get_result_html(self) -> str:
        return self._profiler.output_html()
    
    def get_result_text(self, color=True) -> str:
        return self._profiler.output_text(color=color)