CODEWITHSUNDEEP
python-3.xpython-asyncioaiohttp
rickcoup
rickcoup

Reputation: 275

Where is it stuck with 300 seconds on python aiohttp

I have two simple services running on local. (code is below). Why the response coming back in a very long 300 seconds when I send 100 requests at the same time. What is it doing behind the scene?

Service #1, by calling http://localhost:8080

import os
os.environ['PYTHONASYNCIODEBUG'] = '1'
import json

from aiohttp import web
import aiohttp
import asyncio
import importlib
import time

#tasks = []
n = 0
m = 0

def mcowA(m):
   print (m, " : A") 
   return

async def fetch(session, url):
    try:
        async with session.get(url) as response:
        #async with getattr(session,"get")(url,proxy=proxy) as response:
            return await response.text()
    except Exception:
        import traceback
        traceback.format_exc()

def mcowB(n):
   print (n, " : B") 
   return

async def runMcows(request):
    start = time.time()
    global n,m
    mcowA(m)
    m=m+1
    async with aiohttp.ClientSession() as session:
        html = await fetch(session, 'http://localhost:8081')
        #html = await fetch(session, 'http://www.cpan.org/SITES.htm
    print(n,html)
    mcowB(n)
    end = time.time()
    print ( end - start)
    n=n+1

    return web.Response(text=html)

async def init():
    app = web.Application()
    app.add_routes([web.get('/', runMcows)])
    return await loop.create_server(
        app.make_handler(), '127.0.0.1', 8080)

loop = asyncio.get_event_loop()
loop.run_until_complete(init())
loop.run_forever()

service 2:

from aiohttp import web
import asyncio
import time

async def hello(request):
    time.sleep(5)
    #await asyncio.sleep(5)
    return web.Response(text='dummy done5')

app = web.Application()
app.add_routes([web.get('/', hello)])

web.run_app(app,host='127.0.0.1', port=8081)

I understand the time.sleep(5) is blocking, but why it's blocking 300 seconds? Which part spends the 300 seconds? If changed to await asyncio.sleep(5), it works.

Some of the output: https://github.com/aio-libs/aiohttp/issues/3630

Upvotes: 1

Views: 670

Answers (1)

MarkReedZ
MarkReedZ

Reputation: 1437

This is blocking.

time.sleep(5)

Asyncio isn't threads. An event loop is running which calls your hello function which blocks for 5 seconds before returning. The event loop then regains control and calls the next event which would be your hello function again which would block for another 5 seconds before returning control to the loop.

This waits async for 5 seconds.

await asyncio.sleep(5)

So your hello function returns immediately and simply tells the loop to come back to me in 5 seconds.

Upvotes: 2

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