Hello Tom, Your approach seems comprehensive. I'm commenting on your PR on Trac and GitHub. Let's do this!
Regarding watchdog / watchman, I think Django could select automatically one or the other depending on which on is installed. If none is installed, Django would fall back to the current approach and perhaps raise a warning to suggest installing something better. Regarding the syntax error reloading, I believe the solution is the two-process approach described by Carl earlier in this thread. Check it out. Thanks! -- Aymeric. > On 24 Jul 2017, at 15:58, Tom Forbes <t...@tomforb.es> wrote: > > I was looking into refactoring the auto-reloading code and I wanted to gather > some feedback. There is some potential to squash several bugs in one > go[1][2][3]. > > To begin with we can get rid of the Jython specific code, Jython is 2.7 only > at the moment and I don't think that will change soon. > > We currently have an implicit dependency on `pyinotify`, if it's installed a > more efficient inotify-based watcher is used. I've never seen this advertised > anywhere, and pyinotify has not received any updates in over 3 years. There > is also this[4] blog post which says perhaps pyinotify isn't the best. I > think the best way forward is to use the 'watchdog' package if it's > installed, as it contains platform-specific implementations for observing > file modifications[6] and even their fallback polling observer[7] is better > than any we could include in Django. If we want to add the ability to use the > watchman service with Django (something I fully agree with) perhaps adding > support for it directly to that library would be more preferable than > bundling it in Django itself. > > The current autoreloading code contains some translations specific code that > would be good to split out. It would be nice to have the autoreload module be > as focused as possible on just detecting and handling file changes in a > pretty neutral way, other parts of Django could register subscriptions to be > notified when files change and can handle it themselves (perhaps via > signals?). For example the cached template loader could register a callback > to fire whenever one if it's source files changes and delete that entry from > the cache, the translations framework could handle .mo files changing itself > or third party modules can use these hooks to do whatever crazy things they > want. > > I've got a first-draft branch with a cleanup of the autoreload code here[8], > any feedback would be welcome. It currently doesn't handle syntax error > reloading or the i18n resetting. Could the syntax error reloading be improved > with a clean re-implementation of the autoreloader? I can't think of any nice > ways to handle it. > > 1. https://code.djangoproject.com/ticket/27685#ticket > 2. https://code.djangoproject.com/ticket/25624 > 3. https://code.djangoproject.com/ticket/25791 > 4. http://www.serpentine.com/blog/2008/01/04/why-you-should-not-use-pyinotify/ > 5. https://pythonhosted.org/watchdog/_modules/watchdog/observers/polling.html > 6. https://pythonhosted.org/watchdog/api.html#module-watchdog.observers > 7. https://pythonhosted.org/watchdog/_modules/watchdog/observers/polling.html > 8. > https://github.com/orf/django/blob/27685-autoreloader-refactor/django/utils/autoreload.py > > -- > You received this message because you are subscribed to the Google Groups > "Django developers (Contributions to Django itself)" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to django-developers+unsubscr...@googlegroups.com > <mailto:django-developers+unsubscr...@googlegroups.com>. > To post to this group, send email to django-developers@googlegroups.com > <mailto:django-developers@googlegroups.com>. > Visit this group at https://groups.google.com/group/django-developers > <https://groups.google.com/group/django-developers>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/django-developers/b33d73e3-6ff5-431d-b9ff-7db1219d11cd%40googlegroups.com > > <https://groups.google.com/d/msgid/django-developers/b33d73e3-6ff5-431d-b9ff-7db1219d11cd%40googlegroups.com?utm_medium=email&utm_source=footer>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- You received this message because you are subscribed to the Google Groups "Django developers (Contributions to Django itself)" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To post to this group, send email to django-developers@googlegroups.com. Visit this group at https://groups.google.com/group/django-developers. To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/CAF906F4-A98F-4043-AA79-E60E4789D1EB%40polytechnique.org. For more options, visit https://groups.google.com/d/optout.
