Identifying clients with their User-Agent header

[holasoyender]

This is a suggestion that was discussed on the Discord support server. Related to lavalink-devs/lavalink-client#34, #1135 and holasoyender/lavalink-client@8dfaf59

This pull request adds the option for clients to set a User-Agent header on socket connections and HTTP requests to set extra information about the bot.

Headers example (for websockets)

Authorization: youshallnotpass
User-Id: 170939974227541168
Client-Name: lavalink-client/2.0.0
User-Agent: TestBot/1.0.0

Headers example (for http requests)

Authorization: youshallnotpass
User-Agent: TestBot/1.0.0

When the User-Agent header is set, every log will have a prefix to identify the client its coming from.

[topi314]

I just tested this and there are a few places where this seems to be missing:

• https://github.com/holasoyender/Lavalink/blob/b7ccf2121c2e608fb2f24f627db5fb2f4a2ddc85/LavalinkServer/src/main/java/lavalink/server/io/SocketContext.kt#L249
• https://github.com/holasoyender/Lavalink/blob/b7ccf2121c2e608fb2f24f627db5fb2f4a2ddc85/LavalinkServer/src/main/java/lavalink/server/io/SocketContext.kt#L174
• https://github.com/holasoyender/Lavalink/blob/b7ccf2121c2e608fb2f24f627db5fb2f4a2ddc85/LavalinkServer/src/main/java/lavalink/server/io/SocketContext.kt#L178
• https://github.com/holasoyender/Lavalink/blob/b7ccf2121c2e608fb2f24f627db5fb2f4a2ddc85/LavalinkServer/src/main/java/lavalink/server/player/EventEmitter.kt#L92

additionally your logging format is too different from how lavalink logs used to look
old:
2025-04-12T17:42:28.957+02:00 TRACE 28436 --- [Lavalink] [ XNIO-1 I/O-9] lavalink.server.io.SocketContext : Sent {"op":"playerUpdate","state":{"time":1744472548956,"position":0,"connected":true,"ping":0},"guildId":"1082302532421943407"}

new:
--2025-04-12T17:38:59.899+02:00 -TRACE 9496 --- [ XNIO-1 I/O-15] lavalink.server.io.SocketContext Sent {"op":"playerUpdate","state":{"time":1744472339898,"position":114960,"connected":true,"ping":7},"guildId":"1082302532421943407"}