feat(voice): soft connection limits for voice servers (#2694)

fluxer_admin/src/api/types/voice.rs

@@ -28,6 +28,7 @@ pub struct VoiceServer {
     pub latitude: Option<f64>,
     pub longitude: Option<f64>,
     pub is_active: Option<bool>,
+    pub soft_connection_limit: Option<i64>,
     pub vip_only: Option<bool>,
     #[serde(default)]
     pub required_guild_features: Vec<String>,

fluxer_admin/src/routes/voice.rs

@@ -4,7 +4,7 @@ use crate::{
     api::client::AdminApiClient,
     middleware::{auth::AuthContext, csrf},
     state::AppState,
-    templates,
+    templates::{self, pages::voice_servers::VoiceServersPageParams},
 };
 use axum::{
     Router,
@@ -13,12 +13,34 @@ use axum::{
     routing::get,
 };
 use serde::Deserialize;
+use std::collections::HashMap;
 
 #[derive(Deserialize)]
 struct VoiceServersQuery {
     region_id: Option<String>,
 }
 
+async fn load_server_connection_counts(client: &AdminApiClient) -> HashMap<String, i64> {
+    let response = match client.get_gateway_voice_state_counts().await {
+        Ok(response) => response,
+        Err(error) => {
+            tracing::warn!(%error, "admin API request failed: load voice state counts");
+            return HashMap::new();
+        }
+    };
+    let Some(servers) = response.data.get("servers").and_then(|v| v.as_array()) else {
+        return HashMap::new();
+    };
+    servers
+        .iter()
+        .filter_map(|entry| {
+            let server_id = entry.get("server_id")?.as_str()?.to_owned();
+            let count = entry.get("voice_state_count")?.as_i64()?;
+            Some((server_id, count))
+        })
+        .collect()
+}
+
 pub fn router() -> Router<AppState> {
     Router::new()
         .route(
@@ -79,17 +101,21 @@ async fn voice_servers_page(
             let markup = templates::pages::voice_servers::voice_servers_page(
                 config,
                 &auth.0,
-                None,
-                None,
-                None,
-                None,
-                &csrf_token,
+                &VoiceServersPageParams {
+                    region_id: None,
+                    region_name: None,
+                    servers: None,
+                    connection_counts: &HashMap::new(),
+                    error: None,
+                    csrf_token: &csrf_token,
+                },
             );
             return Html(markup.into_string()).into_response();
         }
     };
 
     let client = AdminApiClient::new(state.http_client(), config, &auth.0.session);
+    let connection_counts = load_server_connection_counts(&client).await;
 
     let region_name = match client.get_voice_region(region_id, false).await {
         Ok(resp) => resp
@@ -107,11 +133,14 @@ async fn voice_servers_page(
             let markup = templates::pages::voice_servers::voice_servers_page(
                 config,
                 &auth.0,
-                Some(region_id),
-                Some(&region_name),
-                Some(&resp.servers),
-                None,
-                &csrf_token,
+                &VoiceServersPageParams {
+                    region_id: Some(region_id),
+                    region_name: Some(&region_name),
+                    servers: Some(&resp.servers),
+                    connection_counts: &connection_counts,
+                    error: None,
+                    csrf_token: &csrf_token,
+                },
             );
             Html(markup.into_string()).into_response()
         }
@@ -120,11 +149,14 @@ async fn voice_servers_page(
             let markup = templates::pages::voice_servers::voice_servers_page(
                 config,
                 &auth.0,
-                Some(region_id),
-                Some(&region_name),
-                None,
-                Some(&msg),
-                &csrf_token,
+                &VoiceServersPageParams {
+                    region_id: Some(region_id),
+                    region_name: Some(&region_name),
+                    servers: None,
+                    connection_counts: &connection_counts,
+                    error: Some(&msg),
+                    csrf_token: &csrf_token,
+                },
             );
             Html(markup.into_string()).into_response()
         }

fluxer_admin/src/routes/voice_actions.rs

@@ -92,6 +92,16 @@ pub(crate) fn build_server_body(form: &MultiValueForm) -> serde_json::Value {
         body.insert("longitude".into(), lng.into());
     }
     body.insert("is_active".into(), form.bool_value("is_active").into());
+    if let Some(raw) = form.first("soft_connection_limit") {
+        let trimmed = raw.trim();
+        if trimmed.is_empty() {
+            body.insert("soft_connection_limit".into(), serde_json::Value::Null);
+        } else if let Ok(limit) = trimmed.parse::<i64>()
+            && limit > 0
+        {
+            body.insert("soft_connection_limit".into(), limit.into());
+        }
+    }
     body.insert("vip_only".into(), form.bool_value("vip_only").into());
     body.insert(
         "required_guild_features".into(),
@@ -255,6 +265,47 @@ mod tests {
         assert_eq!(body["allowed_guild_ids"], serde_json::json!(["1", "2"]));
     }
 
+    #[test]
+    fn build_server_body_sets_soft_connection_limit_from_a_positive_value() {
+        let form =
+            MultiValueForm::parse(b"region_id=us-east&server_id=s1&soft_connection_limit=250");
+        let body = build_server_body(&form);
+        assert_eq!(body["soft_connection_limit"], serde_json::json!(250));
+    }
+
+    #[test]
+    fn build_server_body_clears_soft_connection_limit_when_the_field_is_empty() {
+        let form = MultiValueForm::parse(b"region_id=us-east&server_id=s1&soft_connection_limit=");
+        let body = build_server_body(&form);
+        assert_eq!(body["soft_connection_limit"], serde_json::Value::Null);
+    }
+
+    #[test]
+    fn build_server_body_omits_soft_connection_limit_when_the_field_is_absent_or_invalid() {
+        let absent = MultiValueForm::parse(b"region_id=us-east&server_id=s1&is_active=true");
+        assert!(
+            !build_server_body(&absent)
+                .as_object()
+                .unwrap()
+                .contains_key("soft_connection_limit")
+        );
+        let invalid =
+            MultiValueForm::parse(b"region_id=us-east&server_id=s1&soft_connection_limit=abc");
+        assert!(
+            !build_server_body(&invalid)
+                .as_object()
+                .unwrap()
+                .contains_key("soft_connection_limit")
+        );
+        let zero = MultiValueForm::parse(b"region_id=us-east&server_id=s1&soft_connection_limit=0");
+        assert!(
+            !build_server_body(&zero)
+                .as_object()
+                .unwrap()
+                .contains_key("soft_connection_limit")
+        );
+    }
+
     #[test]
     fn build_server_body_preserves_single_and_repeated_values() {
         let form = MultiValueForm::parse(

fluxer_admin/src/templates/pages/voice_servers.rs

@@ -18,19 +18,33 @@ use crate::{
     },
 };
 use maud::{Markup, html};
+use std::collections::HashMap;
 
 use super::voice_servers_forms::{create_server_form, edit_server_form};
 
+pub struct VoiceServersPageParams<'a> {
+    pub region_id: Option<&'a str>,
+    pub region_name: Option<&'a str>,
+    pub servers: Option<&'a [VoiceServer]>,
+    pub connection_counts: &'a HashMap<String, i64>,
+    pub error: Option<&'a str>,
+    pub csrf_token: &'a str,
+}
+
 pub fn voice_servers_page(
     config: &AdminConfig,
     auth: &AuthContext,
-    region_id: Option<&str>,
-    region_name: Option<&str>,
-    servers: Option<&[VoiceServer]>,
-    error: Option<&str>,
-    csrf_token: &str,
+    p: &VoiceServersPageParams<'_>,
 ) -> Markup {
     let base = &config.base_path;
+    let VoiceServersPageParams {
+        region_id,
+        region_name,
+        servers,
+        connection_counts,
+        error,
+        csrf_token,
+    } = *p;
     let options = LayoutOptions {
         csrf_token,
         inspected_voice_region_id: region_id,
@@ -67,7 +81,7 @@ pub fn voice_servers_page(
                     html! {},
                 ))
                 @if let Some(servers) = servers {
-                    (servers_list(config, rid, servers, csrf_token))
+                    (servers_list(config, rid, servers, connection_counts, csrf_token))
                 }
                 div id="create" class="mt-8" {
                     (create_server_form(config, rid, csrf_token))
@@ -109,6 +123,7 @@ fn servers_list(
     config: &AdminConfig,
     region_id: &str,
     servers: &[VoiceServer],
+    connection_counts: &HashMap<String, i64>,
     csrf_token: &str,
 ) -> Markup {
     if servers.is_empty() {
@@ -121,7 +136,7 @@ fn servers_list(
     html! {
         div class="space-y-4" {
             @for server in servers {
-                (server_card(config, region_id, server, csrf_token))
+                (server_card(config, region_id, server, connection_counts.get(&server.server_id).copied(), csrf_token))
             }
         }
     }
@@ -131,6 +146,7 @@ fn server_card(
     config: &AdminConfig,
     region_id: &str,
     server: &VoiceServer,
+    connection_count: Option<i64>,
     csrf_token: &str,
 ) -> Markup {
     let base = &config.base_path;
@@ -145,6 +161,15 @@ fn server_card(
     let lng_str = server
         .longitude
         .map_or_else(|| "Region default".to_string(), |v| v.to_string());
+    let soft_limit_str = server
+        .soft_connection_limit
+        .map_or_else(|| "No limit".to_string(), |v| v.to_string());
+    let connections_str =
+        connection_count.map_or_else(|| "Unavailable".to_string(), |v| v.to_string());
+    let at_soft_limit = matches!(
+        (server.soft_connection_limit, connection_count),
+        (Some(limit), Some(count)) if limit > 0 && count >= limit
+    );
 
     card(html! {
         div class="mb-4 flex flex-col gap-1" {
@@ -155,6 +180,9 @@ fn server_card(
                 } @else {
                     (badge("INACTIVE", BadgeVariant::Default))
                 }
+                @if at_soft_limit {
+                    (badge("AT SOFT LIMIT", BadgeVariant::Warning))
+                }
                 (voice_status_badges(vip_only, has_features, has_guild_ids))
             }
             p class="text-sm text-neutral-500" { (endpoint) }
@@ -164,6 +192,8 @@ fn server_card(
             (data_field_text("Status", if is_active { "Active" } else { "Inactive" }))
             (data_field_text("Latitude", &lat_str))
             (data_field_text("Longitude", &lng_str))
+            (data_field_text("Soft connection limit", &soft_limit_str))
+            (data_field_text("Live connections", &connections_str))
         }
         (voice_features_list(&server.required_guild_features))
         (voice_guild_ids_list(&server.allowed_guild_ids))

fluxer_admin/src/templates/pages/voice_servers_forms.rs

@@ -26,6 +26,9 @@ pub fn edit_server_form(
     let lat_val = server.latitude.map_or_else(String::new, |v| v.to_string());
     let lng_val = server.longitude.map_or_else(String::new, |v| v.to_string());
     let is_active = server.is_active.unwrap_or(false);
+    let soft_limit_val = server
+        .soft_connection_limit
+        .map_or_else(String::new, |v| v.to_string());
     let vip_only = server.vip_only.unwrap_or(false);
     let features_csv = server.required_guild_features.join(", ");
     let guild_ids_csv = server.allowed_guild_ids.join(", ");
@@ -57,6 +60,15 @@ pub fn edit_server_form(
                         "Optional per-server coordinate override",
                     ))
                 }
+                (form_field_with_helper(
+                    "Soft Connection Limit",
+                    &format!("{id_prefix}-soft-connection-limit"),
+                    "soft_connection_limit",
+                    "number",
+                    &soft_limit_val,
+                    "Leave empty for no limit",
+                    "Placement prefers another server once this server holds this many connections",
+                ))
                 (form_field_with_helper(
                     "API Key",
                     &format!("{id_prefix}-api-key"),
@@ -105,6 +117,15 @@ pub fn create_server_form(config: &AdminConfig, region_id: &str, csrf_token: &st
                 (form_field_with_id("API Secret", "new-server-api-secret", "api_secret", "password", "", "LiveKit API secret", true))
                 (form_field_with_id("Latitude (optional)", "new-server-latitude", "latitude", "number", "", "40.7128", false))
                 (form_field_with_id("Longitude (optional)", "new-server-longitude", "longitude", "number", "", "-74.0060", false))
+                (form_field_with_helper(
+                    "Soft Connection Limit (optional)",
+                    "new-server-soft-connection-limit",
+                    "soft_connection_limit",
+                    "number",
+                    "",
+                    "Leave empty for no limit",
+                    "Placement prefers another server once this server holds this many connections",
+                ))
             }
             div class="space-y-3" {
                 (checkbox("is_active", "true", "Server is active", true, true))