running on multiple computers at once causes failing syncs

simon-weber / Autoplaylists-for-Google-Music

Adds autoplaylists, aka iTunes "smart playlists", to Google Music.

https://autoplaylists.simon.codes

MIT License

93 stars 18 forks source link

running on multiple computers at once causes failing syncs #78

Open johnrobertlawson opened 8 years ago

johnrobertlawson commented 8 years ago

I've had similar problems before, that have appeared again, where my auto playlist is not updating unless I tweak the formula (e.g. limit playlist to 998 instead of 999). I'm not sure if this is related to high battery usage on my Android phone for Google Play Music - like it's refreshing constantly and failing. I also wonder if my problems are related to having Chrome installed and in use on three different computers.

Let me know which logs might be useful in diagnosing problems.

simon-weber commented 8 years ago

Hm, sorry about that.

It's possible that running the extension on multiple computers at once could be causing problems, since each extension assumes it has exclusive access to your playlists. If you notice yourself having problems, can you try shutting down chrome on all but one computer to check if that fixes it? If so, it shouldn't be too hard to fix that in code.

If that doesn't do it, can you try to log both the failing and successful syncs? Something like:

get into a state where syncs are failing
open the logs
clear any existing logs
wait for a minute or so to log failing syncs
make changes to the playlist so syncs succeed again
wait for successful syncs
output all the logs as a file and either post here or email them to me

johnrobertlawson commented 8 years ago

After a few days, it looks like this has been fixed with your suggestion. Having Chrome open on multiple devices seems to break it. (Though not entirely sure this is true, as there has to be a first Chrome instance on either on my computers when it could sync?) I'll keep an eye on it and send logs in there's a problem again.

simon-weber commented 8 years ago

Ok, good to know. I'll rename the issue accordingly.

I'm thinking we could add some locking through sync storage to fix this.

simon-weber commented 7 years ago

I think https://github.com/simon-weber/Autoplaylists-for-Google-Music/issues/97 will help. It seemingly applies updates atomically, and the deletes are also idempotent.

Creates could still race, though:

client 1 pulls cache
client 2 pulls cache
client 1 commits update
client 2 commits update

In this situation you'd end up with the playlist appended to itself, since client 2 didn't know to delete the tracks that client 1 just added.

bryanjmckinnon commented 7 years ago

My issue is I can no longer add new playlists.

I can delete playlists, and that syncs fine. I can modify existing playlists, and that syncs fine. I can no longer add any new playlists. They just don't show up.

I have 2 pc's and an adroid, so possibly ran simultaneously on chrome in 2 locations.

Any ideas how to fix this?

simon-weber commented 7 years ago

Hey Bryan! I'm not entirely sure it's related, so I made a new issue that we can discuss this in: https://github.com/simon-weber/Autoplaylists-for-Google-Music/issues/156.