CookieJar improvements

[Dreamsorcerer]

While looking through #7577, we found a few details that could possibly be improved.

• It should really output duplicate cookies in the Cookie header (e.g. when cookies with different paths have the same name) to match the recommended behaviour in the spec. This may be fairly complex to refactor, as the cookies/morsels used from http.cookies don't seem to support this. Upon reviewing the documentation, I get the impression that http.cookies is intended for server-side, while http.cookiejar is intended for client-side. So, we may need to replace http.cookies to support this behaviour.
• Cookies are now ordered by path length, but it should also use creation timestamp as a tie-breaker (point 2: https://www.rfc-editor.org/rfc/rfc6265.html#section-5.4). This is probably most relevant if cookies with the same name and path match (but different domains, like a root domain and subdomain). I don't think we currently store creation timestamp, so we'd probably need to add this.
• (Implement filter_cookies() with domain-matching and path-matching #7944) .filter_cookies() currently just iterates over all cookies and checks each one if they are valid. This could be made more efficient because they are stored like self._cookies[(domain, path)][name], therefore we could do domain-matching and path-matching on the keys, instead of testing every single cookie.

  aiohttp/aiohttp/cookiejar.py

  Lines 141 to 142 in 4639b36

  	for val in self._cookies.values():
  	yield from val.values()

[Rongronggg9]

I profiled my program with yappi and found that .filter_cookies() consumed 27.5% (23.1s/83.9s) of the total CPU time consumed by requests.

As we can see, the preparation before filtering is very expensive.

aiohttp/aiohttp/cookiejar.py

Lines 237 to 252 in 7ed2dd3

	self._do_expiration()
	if not isinstance(request_url, URL):
	warnings.warn(
	"The method accepts yarl.URL instances only, got {}".format(
	type(request_url)
	),
	DeprecationWarning,
	)
	request_url = URL(request_url)
	filtered: Union["SimpleCookie[str]", "BaseCookie[str]"] = (
	SimpleCookie() if self._quote_cookie else BaseCookie()
	)
	hostname = request_url.raw_host or ""
	request_origin = URL()
	with contextlib.suppress(ValueError):
	request_origin = request_url.origin()

However, not all requests will have cookies in their jar, for example, the initial request, or, when the session is only used to request those URLs that never sent cookies (images, videos, files, etc).

So I have another suggestion: test if there are any cookies in the jar before really doing anything.

[Dreamsorcerer]

Open PRs that probably resolve these performance issues: #7784 #7777 #7790

[Rongronggg9]

Open PRs that probably resolve these performance issues: #7784 #7777 #7790

I see. But they do not eliminate the need to call URL.origin(), which is also expensive, even when the jar is empty. Would you think that my suggestion is a good idea? If so, I can open a PR.

[Dreamsorcerer]

If it's an easy change, feel free to make a PR, it's easier for me to evaluate the code.

[bdraco]

I see. But they do not eliminate the need to call URL.origin(), which is also expensive, even when the jar is empty. Would you think that my suggestion is a good idea? If so, I can open a PR.

I see origin being expensive in the profile as well. Its much more expensive if its an ip address instead of a hostname because it has to recreate the ip_address object. I think you'll need to do another PR for that one

[bdraco]

It would be nice if we had a simple benchmark script to compare before and after changes for the cookie jar (probably the url dispatcher as well).

The cookie jar and the url dispatcher tend to be the bottlenecks for large aiohttp installs so anything we can do to improve them will make things scale much better.

[Dreamsorcerer]

This is a benchmarks repo, which I've not looked at yet, maybe if that is dusted off it can be used?
https://github.com/aio-libs/aiohttp-benchmarks

[bdraco]

It looks like those are mostly? end-to-end benchmarks. Since we already know where the bottlenecks are, I'd be more interested in something that adds 10000 cookies to the cookie jar and does timing on how long it takes to call filter_cookies. Probably one should have an ip address in the url, and one should have a hostname.

For the url dispatcher add 5000 resources and see how much time it takes to dispatch to the to the last one in the list vs the first one in the list.