asyncio: "relative *delay* or absolute *when* should not exceed one day"

[1st1]

BPO	34263
Nosy	@vstinner, @asvetlov, @MartinAltmayer, @1st1
PRs	bpo-34263 Cap timeout submitted to epoll/select etc. to one day. #8532 [3.7] bpo-34263 Cap timeout submitted to epoll/select etc. to one day. (GH-8532) #8586 [3.6] bpo-34263 Cap timeout submitted to epoll/select etc. to one day. (GH-8532) #8587

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = None
closed_at = <Date 2018-07-31.15:32:43.714>
created_at = <Date 2018-07-28.13:49:09.019>
labels = ['3.7', '3.8', 'expert-asyncio']
title = 'asyncio: "relative *delay* or absolute *when* should not exceed one day"'
updated_at = <Date 2018-07-31.15:32:43.713>
user = 'https://github.com/1st1'

bugs.python.org fields:

activity = <Date 2018-07-31.15:32:43.713>
actor = 'yselivanov'
assignee = 'none'
closed = True
closed_date = <Date 2018-07-31.15:32:43.714>
closer = 'yselivanov'
components = ['asyncio']
creation = <Date 2018-07-28.13:49:09.019>
creator = 'yselivanov'
dependencies = []
files = []
hgrepos = []
issue_num = 34263
keywords = ['patch']
message_count = 7.0
messages = ['322561', '322572', '322668', '322777', '322786', '322787', '322788']
nosy_count = 4.0
nosy_names = ['vstinner', 'asvetlov', 'MartinAltmayer', 'yselivanov']
pr_nums = ['8532', '8586', '8587']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue34263'
versions = ['Python 3.7', 'Python 3.8']

[1st1]

asyncio documentation has this bit on timeouts:

Timeouts (relative *delay* or absolute *when*) should not exceed one day.

Victor told me that the actual reason for this recommendation is a limitation in epoll (or other OS/selector) that prevents us from waiting for events longer than a day or so.

The solution to this problem is simple: we need to cap the maximum time we pass to the "selector.select()" function (in base_events.py/_run_once) to one day.

[MartinAltmayer]

Added a small PR. Shall we update the doc? With this PR there is no reason anymore to disallow timeouts greater than one day in asyncio.

Greetings from the sprints @ Edinburgh!

[vstinner]

For python 3.7, i suggest to fix the bug but don't remove the note from 3.7 doc, dince 3.7.0 and older have the bug.

[1st1]

New changeset 944451c by Yury Selivanov (MartinAltmayer) in branch 'master':
bpo-34263 Cap timeout submitted to epoll/select etc. to one day. (GH-8532)
944451c

[1st1]

New changeset 6f16ffc by Yury Selivanov (Miss Islington (bot)) in branch '3.6':
[3.6] bpo-34263 Cap timeout submitted to epoll/select etc. to one day. (GH-8532) (GH-8587)
6f16ffc

[1st1]

New changeset 172a81e by Yury Selivanov (Miss Islington (bot)) in branch '3.7':
[3.7] bpo-34263 Cap timeout submitted to epoll/select etc. to one day. (GH-8532) (GH-8586)
172a81e

[1st1]

Merged. Thank you, hope that you'll keep contributing! :)