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Enrichment pipeline

src/enrich.rs· 190 lines src/a2s.rs· 331 lines

Enrichment is everything beyond "which game, from when to when". It runs on every tick while a session is open and enrich = true, and it is wholly best-effort: enrich::analyze returns an Enrichment value, never an error.

The three sources​

src/enrich.rs
pub fn analyze(client: &SteamClient, a2s: &mut A2sClient, me: u64, game: &CurrentGame) -> Enrichment {
    let Ok(friends) = client.friends(me) else { return Enrichment::default(); };
    let ids: Vec<u64> = friends.iter().map(|f| f.steam_id).collect();
    let Ok(summaries) = client.summaries(&ids) else { return Enrichment::default(); };
    let (server, map) = server_and_map(a2s, game);
    build(&summaries, game, map, server)
}

Note the ordering: if the friend list or the batch summaries call fails, analyze returns completely empty enrichment — including server and map, which would otherwise have been available. That is a deliberate simplification, not an oversight; the next tick tries again.

① and ② — friends playing the same game​

GetFriendList returns SteamIDs only, so a second call (GetPlayerSummaries, chunked at Steam's 100-ID limit) resolves names and current activity. Matching is a single comparison:

summaries.iter().filter(|s| s.game_id == Some(game.app_id))
  • Compared on AppID, not title, so localisation and gameextrainfo differences do not matter.
  • Results are sorted and de-duplicated by persona name — two friends with the same display name collapse into one entry.
  • Only your friends are considered; the tracked account is never in its own friend list, so you never appear in your own friends_playing.
  • A friend whose profile hides game details simply has no gameid and is invisible here.

② — friends in the same lobby​

let Some(lobby) = game.lobby_steam_id.as_deref() else { return Vec::new(); };
summaries.iter().filter(|s| s.lobby_steam_id.as_deref() == Some(lobby))

The lobby is identified by the opaque lobbysteamid string Steam reports for both you and your friends. Exact string equality means "the same Steam lobby".

:::info Why the field is often missing lobbysteamid is only reported for games that use Steam lobbies (P2P matchmaking, party systems built on ISteamMatchmaking). Games with their own matchmaking (most dedicated-server shooters) never expose it, and the field is simply omitted from the log. There is no fallback heuristic — "same server" is not treated as "same lobby". :::

Note that friends_in_lobby is not filtered by game: in practice a shared lobby ID implies the same game, so the extra check is unnecessary.

③ — server name and current map​

If Steam reports a gameserverip (ip:port), SteamLogger sends an A2S_INFO query straight to that address over UDP — no Steam involvement:

Only the first two strings of the reply — server name and map — are kept; everything after them is ignored. Timeout is 3 seconds, and any failure (timeout, ICMP unreachable, malformed packet, repeated challenge) yields (None, None) so the entry keeps its other fields.

Protocol specifics, byte layouts and two known deviations from Valve's spec are documented in the a2s reference.

Assembly​

Enrichment {
    map,
    server,
    friends_playing: same_game_friends(summaries, game),
    friends_in_lobby: lobby_friends(summaries, game),
}

main then calls Tracker::apply_meta, which stores empty vectors as None so that empty arrays never reach the JSON.

What enrichment costs​

Requests per tickBandwidthFails how?
GetFriendList1 HTTPSsmallaborts the whole enrichment pass
GetPlayerSummaries (friends)ceil(n/100) HTTPS~1 KB per friendaborts the whole enrichment pass
A2S_INFO1–2 UDP datagrams< 2 KBonly server/map are lost

Setting enrich = false removes all of it: one Steam call per tick, zero UDP, and only name/start/end in the log.

Limits worth repeating​

  • Snapshot, not timeline. Fields describe the latest poll, not the whole session. A friend who played for ten minutes and left is only recorded if a poll happened while they were in-game, and is dropped from the entry on the next successful enrichment pass.
  • Names, not IDs. The log stores persona names, which users can change at any time. There is no stable identifier in the output format.
  • Private profiles are invisible, both yours (nothing is logged at all) and your friends' (they never appear in friends_playing).
  • No retries inside a tick. Every source gets exactly one attempt per poll.