Auto-reload

[funkyfuture]

This is an auto-reload feature. I used it successfully in conjunction with Simpletask Cloudless and BTsync.
But it may have quirks on race conditions.

could solve #92

[mNantern]

Ok, I checkout your code. I will try that this week but at first sight it works well !

It remains only #59 before launching QTodoTxt v1.4 (or 2.0 ?) !

[funkyfuture]

before releasing a next Major release, i would improve at least some of the following aspects:

• a more intuitive backend-API, like proposed in implement classes for task components #94
• more signaling between components
• CSS-theming
• usage of .ui-files
• a comprehensive code-review with a ot lof in-source-documentation (atm one can still figure out how something is supposed to work, but it's not that intutive and there are inconsistencies)

[mNantern]

@funkyfuture : I just try the auto-reload with QTodoTxt on MacOs and Windows and I always have an exception here on Windows:

[Errno 13] Permission denied: 'path to my Dropbox file'

Looks like we try to openFileByName before the file is completely written. It happens only when I close or delete a task on Mac. Creating or modifying a task is correctly replicated.
Adding a (ugly) sleep(1) before loading the file works

[funkyfuture]

i think i will add some debbugging-statements and maybe some tests into it within the next days to really understand what's going on.

[funkyfuture]

and by "closing" a task, you mean to mark it as completed? just not to misunderstand you.

[mNantern]

Yes, It was when I tried to complete a task.

[funkyfuture]

at which point did you put the sleep(1) exactly?

anyway, i think we can get a better insight now with debug-logging enabled.

[funkyfuture]

i just noticed that the logging doesn't actually doesn't take into account what is set as cli-parameter. it will log anyway.
but i will go to bed now.

[mNantern]

I put the sleep just before self.parent().openFileByName(self._file.filename)

[mNantern]

Ok I made more test and I just find the sleep solution. Even a 10ms sleep is enough so I will let that until we find a better solution.

Version 1.4 is now feature complete, I will test it during 1 week and if everything is ok I will release it !

[mattiasdh]

Cool, looking forward to it! 👍

[funkyfuture]

@mNantern could you please post the logs for the problematic situation with and without the 10msec-sleep?

[mNantern]

@funkyfuture :

With the sleep:

19:58:44.26 [qtodotxt.lib.file] DEBUG: Setting up FileObserver instance.
19:58:44.36 [qtodotxt.ui.controllers.main_controller] DEBUG: MainController.openFileByName called with filename="C:/Users/Matt/Dropbox/todotxt/todo.txt"
19:58:44.186 [qtodotxt.ui.controllers.main_controller] DEBUG: Adding C:/Users/Matt/Dropbox/todotxt/todo.txt to watchlist
19:59:11.546 [qtodotxt.lib.file] DEBUG: Detected change on C:/Users/Matt/Dropbox/todotxt/todo.txt
removing it from watchlist
19:59:11.556 [qtodotxt.ui.controllers.main_controller] DEBUG: MainController.openFileByName called with filename="C:/Users/Matt/Dropbox/todotxt/todo.txt"
19:59:11.566 [qtodotxt.ui.controllers.main_controller] DEBUG: Adding C:/Users/Matt/Dropbox/todotxt/todo.txt to watchlist
19:59:19.556 [qtodotxt.lib.file] DEBUG: Detected change on C:/Users/Matt/Dropbox/todotxt/todo.txt
removing it from watchlist
19:59:19.566 [qtodotxt.ui.controllers.main_controller] DEBUG: MainController.openFileByName called with filename="C:/Users/Matt/Dropbox/todotxt/todo.txt"
19:59:19.576 [qtodotxt.ui.controllers.main_controller] DEBUG: Adding C:/Users/Matt/Dropbox/todotxt/todo.txt to watchlist

Without I can't reproduce it. I hate this bug !

It happens with every other log level (maybe that's just because logging in DEBUG takes time and so the micro sleep is not needed anymore...):

QTodoTxt\bin [master +1 ~1 -1 !]> .\qtodotxt.py -l INFO
[Errno 13] Permission denied: 'C:/Users/Matt/Dropbox/todotxt/todo.txt'

[funkyfuture]

hmpf, so i guess a
if os.name == 'nt: sleep(0.01)
would help as much as the debugging.

i'd actually prefer a more controlled approach than a fixed time since you can't know the race conditions of a system.
shall i try something that does condition checks?

[mNantern]

What do you mean by "condition checks" ?

Ok, I will add a check on the OS name but I think that this feature is good like that. We can release it and see what bug we get :)

[funkyfuture]

no, i mean that an OS-check would have the same effect as the debug-logging. it's useless.

with conditioncheck i mean it should be tested if the file can be opened. if not, wait until it can be. because you can't know if 10msec are enough on every system.

[mNantern]

With that every system (Mac and Linux) will pay the additional call to open.

We can leave it like that and when catching an Exception wait a few millisecs (10 for example) and call again openFileByName. We should also limit the number of retry to 3.

Something like that:

    def retryOpen(self,filename,retryNumber):
     while retryNumber < 3:
           retryNumber += 1
           try:
               self.parent().openFileByName(self._file.filename)
           except ErrorLoadingFile:
              sleep(0.01)
              retryOpen(self._file.filename,retryNumber)

What do you think ?

[funkyfuture]

i would avoid recursions as much as possible. beside that i think another method is too much for that issue.

i made a change that will try to read the file within a maximum of one second. i think that is still reasonable for a fluent user experience and should also work on slower machines.

here's the commit: 042f4b2

[mNantern]

I will test that today. Seems ok even if they are no more the beauty of recursion 😜

[mNantern]

It was almost working, just missing a last "break" statement to not keep looping until 1 sec passed.

I think we are good for a release tomorrow.

Thanks a lot for your hard work !