Fix task interference bugs and task repeating

[rtibbles]

• Simplifies how we use task manager to only use single enqueuing of a task, and rely on Kolibri's task requeuing within the life cycle of a task to handle repeat behaviour
• Updates to always use APPEND_OR_REPLACE to ensure that tasks append while running or replace if not running.
• Updates Python for Android to a version on our fork that allow defining a main function in the specified module that will be executed if it exists - it is passed what would normally be passed as the environment variable argument as its sole argument
• This helps prevent the environment variable getting set to the incorrect value when multiple threads are operating (as they do in the work manager context) - this means that job execution will always be passed the proper job_id, and not accidentally read the incorrect job_id from either from an environment variable or a variable set on the __main__ module that is shared across threads.

I tested this with a dummy task defined in the android_app_plugin that used the retry_in method of the job object to repeat itself every 5 seconds. It did this successfully, and also did not interfere or attempt to run other currently active tasks (such as the ping back task or the network connection checking task) which I had seen in previous testing.

Full diff for the change in our P4A fork here: learningequality/python-for-android@4a3c74c...5eff8c9

[pcenov]

Hi @rtibbles syncing is working correctly now and the only potential issue that I was able to identify is that the sync status displayed at Coach > Class home > View learners never changes from 'Synced' to 'Not connected to server' (after having force stopped the app) - had to wait for about 20 minutes for it to change to 'Not recently synced or unable to sync'.

There are some errors in the logs such as:

ERROR 2023-11-02 13:17:57,394 kolibri.core.device.soud [user=2389bbe0d3cf341764625349a5c594e8] [server=6a40d55608b125e4a9e45fb854476922] Critical error occurred during syncing: Stage `cleanup` failed
ERROR 2023-11-02 13:17:57,466 kolibri.core.device.soud Stage `cleanup` failed

so adding the logs for you to review as well:

Android device:
android.zip
ubuntu_server.zip

[rtibbles]

Thanks @pcenov - looking at the logs, I don't think that's the result of this work, but I'll ask around to see!

[rtibbles]

Yes, have filed a follow up on Kolibri: learningequality/kolibri#11485 - so I think this PR is doing what it ought!

[pcenov]

@rtibbles it seems that there's still something wrong with the app though. Now it has stopped syncing (for a brand new learner user) so once again adding the logs.

The server is the same as before:

Android2.zip

ubuntu_server2.zip

[jredrejo]

Tested and syncing task is working well, even using an user migrated from a tablet to the server.
For the code I'm not totally sure because I don't know completely the inner details of the task system in Android but https://developer.android.com/reference/androidx/work/WorkManager#enqueueUniqueWork(java.lang.String,androidx.work.ExistingWorkPolicy,java.util.List%3Candroidx.work.OneTimeWorkRequest%3E) seems to be done exactly for the purpose this PR is using it so it looks ok.

On the other hand I've seen several error messages in the server. They don't look related to this PR but I'll follow them on a separate thread/issue.

[rtibbles]

@pcenov looking at the logs, this seems unrelated to Android specifically, so I have filed the error I saw in the logs as a follow up issue here: learningequality/kolibri#11488