[issue12410] Create a new helper function that enable to test that an operation don't hang more than a given timeout.
Charles-François Natali neolo...@free.fr added the comment: Closing, since it's hard to write correctly, and apparently not that useful. -- resolution: - rejected stage: - committed/rejected status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue12410 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue12410] Create a new helper function that enable to test that an operation don't hang more than a given timeout.
New submission from mouad mouad...@gmail.com: While working on issue #12157 [http://bugs.python.org/issue12157], I needed a function that make sure that an operation will not hang forever, for this reason i have create this helper function that support the context manager protocol and accept a timeout as an argument and raise an IOError if the operation didn't terminate before that timeout. -- components: Tests files: operation_timeout.patch keywords: patch messages: 139075 nosy: mouad priority: normal severity: normal status: open title: Create a new helper function that enable to test that an operation don't hang more than a given timeout. type: feature request versions: Python 3.2 Added file: http://bugs.python.org/file22467/operation_timeout.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue12410 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue12410] Create a new helper function that enable to test that an operation don't hang more than a given timeout.
Changes by mouad mouad...@gmail.com: Removed file: http://bugs.python.org/file22467/operation_timeout.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue12410 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue12410] Create a new helper function that enable to test that an operation don't hang more than a given timeout.
Changes by mouad mouad...@gmail.com: Added file: http://bugs.python.org/file22469/operation_timeout.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue12410 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue12410] Create a new helper function that enable to test that an operation don't hang more than a given timeout.
Changes by R. David Murray rdmur...@bitdance.com: -- nosy: +haypo ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue12410 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue12410] Create a new helper function that enable to test that an operation don't hang more than a given timeout.
Charles-François Natali neolo...@free.fr added the comment: It's a little bit more complicated than that: - signals and threads don't mix well together - this will make syscalls fail with EINTR - the old SIGALRM handler is lost - etc In short, don't use signals. I'm not sure there's a reliable way to write such a general-purpose wrapper (usually one can use select() with a timeout or spawn a subprocess and use communicate's timeout to achieve this kind of things). In your use case (issue #12157), I think that letting the test block is fine, since: - there's no easy way to add a timeout (but you could spawn a new interpreter and use communicate with a timeout if you really wanted to) - it will be caught by the faulthandler module - a test killed by faulthandler's timeout is more interesting to fix that a common failed test ;-) -- nosy: +neologix ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue12410 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue12410] Create a new helper function that enable to test that an operation don't hang more than a given timeout.
mouad mouad...@gmail.com added the comment: Thanks for the instructive feedback :) I totally agree i guess there is a lot of issues that i didn't think of :-(, my first thinking was to use Pool.join timeout argument but it was removed in 3.2 (by the way i didn't find the issue or the rational that lead to this change). And now that i know about faulthandler module i guess that will make also my life easier :), i will rewrite the patch in the issue #12157 to not use any *fancy* way to check if it will hang. cheers, -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue12410 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue12410] Create a new helper function that enable to test that an operation don't hang more than a given timeout.
STINNER Victor victor.stin...@haypocalc.com added the comment: alarm() is one possible implementation, but Charles-François listed some drawbacks. You can also use resource.setrlimit(RLIMIT_CPU), but the timeout is the CPU time (e.g. you cannot stop a sleep) and it is not portable (e.g. resource is not available on Windows). Another possible implementation is a thread. faulthandler uses an hidden thread (implemented in C): a thread ignoring all signals using pthread_sigmask. Python threads are not reliable for a timeout because of the GIL, and it is not easy to interrupt another thread from the timeout thread. For example, you cannot (easily) raise an exception in another thread. I'm not sure there's a reliable way to write such a general-purpose wrapper I agree, but it doesn't mean that it is not possible :-) I think that you should try to implement in C a thread ignoring all signals. It becomes more complex when you have to implement the interrupt the current thread (current thread, or maybe the thread using the operation_timeout context manager?) part. I suppose that you will have to use low-level tricks and you will have to experiment your tool on different platform. You should start this project outside CPython (as a third party module), and then ask for an integration when your work is well tested. You have to know that a module dies when it enters CPython: you have to wait something like 18 months to modify it, so you have to be sure that your code is correct ;-) -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue12410 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue12410] Create a new helper function that enable to test that an operation don't hang more than a given timeout.
STINNER Victor victor.stin...@haypocalc.com added the comment: Oh, there is another possible implementation: use a subprocess. But if the timeout is implemented using a subprocess, the syntax cannot be: with timeout(5): do_something() It should be something like: timeout(5, if 1: import os, sys ... do_something() ... sys.exit(0) ) Some tests are already doing that manually. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue12410 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
