Event driven updates

[themcclure]

"Epic" to cover the user story: this should become a long running process that updates the playlists after they have been sufficiently listened to to warrant an update.

Questions:

• detecting new media being added and either adding it as a delta or just refreshing the whole thing... I guess it doesn't happen that often... would a refresh to include new media keep the living track data?
• what about track data that changes on the server? Does the API just "know" to fetch it again? eg if a track is rated, will that just magically reload? Or will it be stale until manually refreshed... but how do we do that?

Triggering the job:

• Is websockets viable? (and using PlexServer.Alert())
• Plex webhooks to trigger something?
• SOME kind of monitoring that puts events on a queue until there are "enough"
• can we avoid having to implement queueing in some way (Celery, Cloud Tasks)?

Processing the job:

• can we measure the "last played" date of a playlist?
• cold startup time is long... like 2 minutes to connect, 1 minute to get the track list and 3 minutes to fetch track data. Once fetched the track data can be used without further Plex API call for ??? (>15) minutes so maybe it's only going to be an issue if there's new media
• can we tell is Plex events are coming from playlist plays, or at least songs in a playlist?
• perhaps after THRESHOLD % of songs in a playlist have been played, refresh that playlist?
• perhaps just a daily/weekly job to see if things have moved enough to trigger?
• can we force sync the devices who have synced that playlist?

delivery & packaging:

• can it be run on cloud infrastructure?
• can ultimate location still be triggered manually, or will I also have to keep working on the PlexCLI?
• can it be dockerized to run on a low powered local server?