Add prometheus metric for item counts

[clbx]

Changes

Updated the prometheus metrics endpoint written by @holahmeds in #6882 to be up to date with main.

Adds jellyfin_library_items_total to the metrics endpoint which will return the amount of every item in the library.

• Audio
• Book
• Episode
• Movie
• MusicAlbum
• MusicArtist
• MusicVideo
• Photo
• PhotoAlbum
• Season
• Series

Issues

Contributes to #3016

[clbx]

@robertas90poe you approved the original PR for this not too long ago, could you take a look at this?

[robertas90poe]

lgtm

[clbx]

@cvium you had commented on the previous iteration of this PR, could you take a look?

[cvium]

Honestly, it's not great that it relies on DB queries. The database is already heavily abused.

[clbx]

Gotcha, I will look into ways to get the information without continuously querying the database when I have some free time. Thanks for taking a look.

[jellyfin-bot]

This pull request has merge conflicts. Please resolve the conflicts so the PR can be successfully reviewed and merged.

[oddstr13]

While the db queries here is less than great, it would be great to at least get some basic Jellyfin stuff in, like the Jellyfin version (something ala dotnet_build_info for Jellyfin specific info).

Do you think you could create a PR for something really basic, that doesn't depend on any db queries so we can get the ball rolling?

# HELP dotnet_build_info Build information about prometheus-net.DotNetRuntime and the environment
# TYPE dotnet_build_info gauge
dotnet_build_info{version="4.2.4.0",target_framework=".NETCoreApp,Version=v6.0",runtime_version=".NET 6.0.9",os_version="Linux 5.15.0-84-generic #93-Ubuntu SMP Tue Sep 5 17:16:10 UTC 2023",process_architecture="X64",gc_mode="Workstation"} 1

[arthurlutz]

Maybe querying the database is OK if there's a cache or if the target is only scraped every hour ? For this type of data I don't think the granularity needs to be by the minute...

[clbx]

Personally, I think having it cached and then scraped at an interval is an acceptable solution, not necessarily ideal. I spent a little bit of time trying to figure out how to get that information without hitting the database, but I'm not familiar enough with the codebase (or C# really ) to have any success.

[jellyfin-bot]

This pull request has merge conflicts. Please resolve the conflicts so the PR can be successfully reviewed and merged.

[jellyfin-bot]

This pull request has merge conflicts. Please resolve the conflicts so the PR can be successfully reviewed and merged.

[BBArikL]

Is this PR still scheduled for a release? Having more data that could be exported for external metrics collectors would be great!

[DomiiBunn]

@BBArikL

Is this PR still scheduled for a release? Having more data that could be exported for external metrics collectors would be great!

Check out jellystat

[BBArikL]

Jellystat seems interesting but having a dedicated app only for jellyfin feels a litte bit too much. Using prometheus + grafana helps get all the data and visualisation at the same place.