CORE: added prom metrics on /metrics

Cargo.lock

@@ -1418,7 +1418,7 @@ checksum = "e6d5a32815ae3f33302d95fdcb2ce17862f8c65363dcfd29360480ba1001fc9c"
 
 [[package]]
 name = "furumusic"
-version = "0.2.10"
+version = "0.2.11"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -1441,6 +1441,7 @@ dependencies = [
  "symphonia",
  "tokio",
  "tokio-cron-scheduler",
+ "tower",
  "tracing",
  "tracing-subscriber",
  "uuid",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "furumusic"
-version = "0.2.11"
+version = "0.2.12"
 edition = "2024"
 description = "Reusable web-app boilerplate: auth, OIDC/SSO, admin panel, user management, i18n, PostgreSQL"
 
@@ -11,6 +11,7 @@ serde = { version = "1", features = ["derive"] }
 openidconnect = "4.0"
 reqwest = { version = "0.12", default-features = false, features = ["rustls-tls", "json"] }
 tokio = { version = "1", features = ["sync", "fs", "io-util"] }
+tower = "0.5"
 base64 = "0.22"
 serde_json = "1"
 tracing = "0.1"

src/agent/cover_art.rs

@@ -128,13 +128,21 @@ pub async fn find_best_cover(folder: &Path, audio_files: &[PathBuf]) -> Option<C
         match tokio::fs::read(img_path).await {
             Ok(data) if !data.is_empty() => {
                 let mime = mime_for_image(img_path);
+                crate::metrics::record_agent_cover_lookup("folder", "ok", data.len());
                 return Some(CoverImage {
                     data,
                     mime_type: mime,
                     source: CoverSource::FolderFile(img_path.clone()),
                 });
             }
-            _ => continue,
+            Ok(_) => {
+                crate::metrics::record_agent_cover_lookup("folder", "empty", 0);
+                continue;
+            }
+            Err(_) => {
+                crate::metrics::record_agent_cover_lookup("folder", "error", 0);
+                continue;
+            }
         }
     }
 
@@ -143,10 +151,12 @@ pub async fn find_best_cover(folder: &Path, audio_files: &[PathBuf]) -> Option<C
         let path = audio_path.to_path_buf();
         let result = tokio::task::spawn_blocking(move || extract_embedded_cover(&path)).await;
         if let Ok(Some(cover)) = result {
+            crate::metrics::record_agent_cover_lookup("embedded", "ok", cover.data.len());
             return Some(cover);
         }
     }
 
+    crate::metrics::record_agent_cover_lookup("none", "not_found", 0);
     None
 }
 

src/agent/cover_variants.rs

@@ -74,6 +74,7 @@ fn generate_missing_variants_sync(
 
     let mut created = 0usize;
     for variant in variants {
+        let start = std::time::Instant::now();
         let path = variant_path(original_path, *variant);
         if path.exists() {
             continue;
@@ -88,12 +89,27 @@ fn generate_missing_variants_sync(
             .to_rgb8();
         let mut output = Vec::new();
         let mut encoder = JpegEncoder::new_with_quality(&mut output, variant.quality);
-        encoder.encode(
+        let result = encoder.encode(
             &resized,
             resized.width(),
             resized.height(),
             image::ExtendedColorType::Rgb8,
-        )?;
+        );
+        match result {
+            Ok(()) => crate::metrics::record_agent_cover_variant(
+                variant.name,
+                "ok",
+                start.elapsed(),
+            ),
+            Err(err) => {
+                crate::metrics::record_agent_cover_variant(
+                    variant.name,
+                    "error",
+                    start.elapsed(),
+                );
+                return Err(err.into());
+            }
+        }
         std::fs::write(path, output)?;
         created += 1;
     }

src/agent/normalize.rs

@@ -330,6 +330,7 @@ pub async fn normalize_batch(
     // If over 80% of context limit and more than 1 file, split
     let limit_80 = context_limit * 80 / 100;
     if estimated > limit_80 && files.len() > 1 {
+        crate::metrics::record_agent_llm_split("estimated_context");
         tracing::info!(
             estimated_tokens = estimated,
             context_limit,
@@ -419,6 +420,7 @@ pub async fn normalize_batch(
                 || err_str.contains("length")
                 || err_str.contains("token");
             if is_context_error {
+                crate::metrics::record_agent_llm_split("context_error");
                 tracing::warn!(
                     file_count = files.len(),
                     "LLM error suggests context overflow, splitting batch: {e}"
@@ -466,14 +468,40 @@ pub async fn normalize_batch(
             }
             return Err(e);
         }
-        Err(e) => return Err(e),
+        Err(e) => {
+            crate::metrics::record_agent_llm(
+                llm_model,
+                "error",
+                std::time::Duration::from_millis(duration_ms),
+                0,
+                0,
+                files.len(),
+                Some(estimated),
+            );
+            return Err(e);
+        }
     };
 
     let prompt_tokens = usage.prompt_tokens.unwrap_or(0) as u64;
     let completion_tokens = usage.completion_tokens.unwrap_or(0) as u64;
+    crate::metrics::record_agent_llm(
+        &resp_model,
+        "ok",
+        std::time::Duration::from_millis(duration_ms),
+        prompt_tokens,
+        completion_tokens,
+        files.len(),
+        Some(estimated),
+    );
 
     // Parse batch response
-    let results = parse_batch_response(&response_text, &files)?;
+    let results = match parse_batch_response(&response_text, &files) {
+        Ok(results) => results,
+        Err(error) => {
+            crate::metrics::record_agent_llm_parse_failure(&resp_model);
+            return Err(error);
+        }
+    };
 
     Ok(BatchNormalizeResult {
         results,

src/auth.rs

@@ -61,6 +61,7 @@ pub async fn get_session_user(session: &Session, db: &Database) -> Option<Authen
             display
         }
     };
+    crate::metrics::record_active_user(user.id_val());
     Some(AuthenticatedUser {
         id: user.id_val(),
         name,
@@ -75,9 +76,11 @@ pub async fn require_admin_or_redirect(
     db: &Database,
 ) -> Result<AuthenticatedUser, cot::response::Response> {
     let Some(user) = get_session_user(session, db).await else {
+        crate::metrics::record_authorization_denied("unauthenticated");
         return Err(redirect("/login"));
     };
     if user.role != Role::Admin {
+        crate::metrics::record_authorization_denied("forbidden");
         return Err("Forbidden"
             .with_status(cot::http::StatusCode::FORBIDDEN)
             .into_response()
@@ -96,6 +99,7 @@ pub async fn login(session: &Session, user_id: i64) -> cot::Result<()> {
         .insert(SESSION_USER_ID, user_id)
         .await
         .map_err(|e| cot::Error::internal(e.to_string()))?;
+    crate::metrics::record_active_user(user_id);
     Ok(())
 }
 

src/jobs/inbox_discover.rs

@@ -29,6 +29,8 @@ impl Job for InboxDiscoverJob {
     }
 
     async fn run(&self, ctx: &JobContext, log: &mut JobLog) -> anyhow::Result<()> {
+        let run_start = std::time::Instant::now();
+        let run_outcome = "completed";
         // Prevent overlapping discover runs
         if DISCOVER_RUNNING
             .compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst)
@@ -44,6 +46,19 @@ impl Job for InboxDiscoverJob {
             }
         }
         let _guard = Guard;
+        struct MetricsGuard {
+            start: std::time::Instant,
+            outcome: &'static str,
+        }
+        impl Drop for MetricsGuard {
+            fn drop(&mut self) {
+                crate::metrics::record_agent_discover_run(self.outcome, self.start.elapsed());
+            }
+        }
+        let mut metrics_guard = MetricsGuard {
+            start: run_start,
+            outcome: run_outcome,
+        };
 
         let config = &ctx.config;
 
@@ -97,6 +112,7 @@ impl Job for InboxDiscoverJob {
 
                 // Compute SHA-256 hash
                 let path_clone = file_path.to_path_buf();
+                let hash_start = std::time::Instant::now();
                 let (hash, file_size) =
                     match tokio::task::spawn_blocking(move || -> anyhow::Result<(String, i64)> {
                         let data = std::fs::read(&path_clone)?;
@@ -107,8 +123,12 @@ impl Job for InboxDiscoverJob {
                     })
                     .await?
                     {
-                        Ok(v) => v,
+                        Ok(v) => {
+                            crate::metrics::record_agent_file_hash(hash_start.elapsed(), v.1, "ok");
+                            v
+                        }
                         Err(e) => {
+                            crate::metrics::record_agent_file_hash(hash_start.elapsed(), 0, "error");
                             log.warn(&format!("Failed to hash {}: {e}", file_path.display()));
                             continue;
                         }
@@ -125,13 +145,18 @@ impl Job for InboxDiscoverJob {
 
                 // Extract raw metadata
                 let path_for_meta = file_path.to_path_buf();
+                let metadata_start = std::time::Instant::now();
                 let raw_meta = match tokio::task::spawn_blocking(move || {
                     crate::agent::metadata::extract(&path_for_meta)
                 })
                 .await?
                 {
-                    Ok(m) => m,
+                    Ok(m) => {
+                        crate::metrics::record_agent_metadata(metadata_start.elapsed(), "ok");
+                        m
+                    }
                     Err(e) => {
+                        crate::metrics::record_agent_metadata(metadata_start.elapsed(), "error");
                         log.warn(&format!(
                             "Failed to extract metadata from {}: {e}",
                             file_path.display()
@@ -189,6 +214,12 @@ impl Job for InboxDiscoverJob {
             "Discovered {} new files, skipped {} (hash known), skipped {} (already queued)",
             discovered, skipped_hash, skipped_existing
         ));
+        crate::metrics::record_agent_discover_files(
+            audio_files.len() as u64,
+            discovered,
+            skipped_hash,
+            skipped_existing,
+        );
 
         // Trigger inbox_process in background if new files were discovered
         // and no orchestrator is already running
@@ -219,6 +250,7 @@ impl Job for InboxDiscoverJob {
             }
         }
 
+        metrics_guard.outcome = run_outcome;
         Ok(())
     }
 }

src/jobs/inbox_process.rs

@@ -307,12 +307,18 @@ async fn process_folder_batch(
 
         // Extract metadata (with 60s timeout)
         let path_for_meta = file_path.to_path_buf();
+        let metadata_start = std::time::Instant::now();
         let meta_future =
             tokio::task::spawn_blocking(move || crate::agent::metadata::extract(&path_for_meta));
         let raw_meta =
             match tokio::time::timeout(std::time::Duration::from_secs(60), meta_future).await {
-                Ok(Ok(Ok(m))) => m,
+                Ok(Ok(Ok(m))) => {
+                    crate::metrics::record_agent_metadata(metadata_start.elapsed(), "ok");
+                    m
+                }
                 Ok(Ok(Err(e))) => {
+                    crate::metrics::record_agent_metadata(metadata_start.elapsed(), "error");
+                    crate::metrics::record_agent_failed("metadata");
                     let msg = format!("{filename}: metadata error: {e}");
                     log.error(&msg);
                     let _ = review.set_failed(db, &msg).await;
@@ -320,6 +326,8 @@ async fn process_folder_batch(
                     continue;
                 }
                 Ok(Err(e)) => {
+                    crate::metrics::record_agent_metadata(metadata_start.elapsed(), "panic");
+                    crate::metrics::record_agent_failed("metadata");
                     let msg = format!("{filename}: metadata panic: {e}");
                     log.error(&msg);
                     let _ = review.set_failed(db, &msg).await;
@@ -327,6 +335,8 @@ async fn process_folder_batch(
                     continue;
                 }
                 Err(_) => {
+                    crate::metrics::record_agent_metadata(metadata_start.elapsed(), "timeout");
+                    crate::metrics::record_agent_failed("metadata");
                     let msg = format!("{filename}: metadata timeout (60s)");
                     log.error(&msg);
                     let _ = review.set_failed(db, &msg).await;
@@ -416,6 +426,7 @@ async fn process_folder_batch(
     // Lookup all unique artist queries
     let mut all_similar_artists = Vec::new();
     for q in &artist_queries {
+        let rag_start = std::time::Instant::now();
         match tokio::time::timeout(
             std::time::Duration::from_secs(30),
             crate::agent::rag::find_similar_artists(pool, q, 5),
@@ -423,6 +434,7 @@ async fn process_folder_batch(
         .await
         {
             Ok(Ok(results)) => {
+                crate::metrics::record_agent_rag("artist", "ok", rag_start.elapsed(), results.len());
                 for a in results {
                     if !all_similar_artists
                         .iter()
@@ -432,13 +444,20 @@ async fn process_folder_batch(
                     }
                 }
             }
-            Ok(Err(e)) => log.warn(&format!("RAG artist lookup failed for \"{q}\": {e}")),
+            Ok(Err(e)) => {
-            Err(_) => log.warn(&format!("RAG artist lookup timed out for \"{q}\"")),
+                crate::metrics::record_agent_rag("artist", "error", rag_start.elapsed(), 0);
+                log.warn(&format!("RAG artist lookup failed for \"{q}\": {e}"))
+            }
+            Err(_) => {
+                crate::metrics::record_agent_rag("artist", "timeout", rag_start.elapsed(), 0);
+                log.warn(&format!("RAG artist lookup timed out for \"{q}\""))
+            }
         }
     }
 
     let mut all_similar_releases = Vec::new();
     for q in &album_queries {
+        let rag_start = std::time::Instant::now();
         match tokio::time::timeout(
             std::time::Duration::from_secs(30),
             crate::agent::rag::find_similar_releases(pool, q, 5),
@@ -446,6 +465,7 @@ async fn process_folder_batch(
         .await
         {
             Ok(Ok(results)) => {
+                crate::metrics::record_agent_rag("release", "ok", rag_start.elapsed(), results.len());
                 for r in results {
                     if !all_similar_releases
                         .iter()
@@ -455,8 +475,14 @@ async fn process_folder_batch(
                     }
                 }
             }
-            Ok(Err(e)) => log.warn(&format!("RAG release lookup failed for \"{q}\": {e}")),
+            Ok(Err(e)) => {
-            Err(_) => log.warn(&format!("RAG release lookup timed out for \"{q}\"")),
+                crate::metrics::record_agent_rag("release", "error", rag_start.elapsed(), 0);
+                log.warn(&format!("RAG release lookup failed for \"{q}\": {e}"))
+            }
+            Err(_) => {
+                crate::metrics::record_agent_rag("release", "timeout", rag_start.elapsed(), 0);
+                log.warn(&format!("RAG release lookup timed out for \"{q}\""))
+            }
         }
     }
 
@@ -547,11 +573,14 @@ async fn process_folder_batch(
     let batch_result = match llm_result {
         Ok(r) => r,
         Err(e) => {
+            crate::metrics::record_agent_failed("llm");
+            crate::metrics::record_agent_folder_batch("failed", file_count, batch_start.elapsed());
             let err_msg = format!("Batch LLM call failed: {e}");
             log.error(&err_msg);
             // Mark all files as failed
             for mut p in prepared {
                 let _ = p.review.set_failed(db, &err_msg).await;
+                crate::metrics::record_agent_file_processed("failed", "failed");
             }
             let total_fail_count = failed_reviews.len() as u64 + file_count as u64;
             let duration_ms = batch_start.elapsed().as_millis() as i64;
@@ -612,6 +641,7 @@ async fn process_folder_batch(
 
         let result_json = serde_json::to_string(normalized).unwrap_or_default();
         let confidence = normalized.confidence.unwrap_or(0.0);
+        crate::metrics::observe_agent_confidence(confidence);
 
         let feat = if normalized.featured_artists.is_empty() {
             String::new()
@@ -655,9 +685,12 @@ async fn process_folder_batch(
             {
                 Ok(()) => {
                     let _ = p.review.set_auto_approved(db).await;
+                    crate::metrics::record_agent_file_processed("ok", "auto_approved");
                     ok_count += 1;
                 }
                 Err(e) => {
+                    crate::metrics::record_agent_failed("finalize");
+                    crate::metrics::record_agent_file_processed("failed", "failed");
                     let msg = format!("{filename}: finalize failed: {e}");
                     log.error(&msg);
                     let _ = p.review.set_failed(db, &msg).await;
@@ -671,6 +704,7 @@ async fn process_folder_batch(
             )
             .unwrap();
             let _ = p.review.save(db).await;
+            crate::metrics::record_agent_file_processed("ok", "pending_review");
             log.info(&format!(
                 "{filename}: manual review (confidence {confidence} < {})",
                 config.agent_confidence_threshold,
@@ -682,9 +716,11 @@ async fn process_folder_batch(
     let duration_ms = batch_start.elapsed().as_millis() as i64;
     if fail_count == 0 {
         let _ = run.set_completed(db, duration_ms, &log.output()).await;
+        crate::metrics::record_agent_folder_batch("completed", file_count, batch_start.elapsed());
     } else {
         let msg = format!("{fail_count} file(s) failed");
         let _ = run.set_failed(db, duration_ms, &log.output(), &msg).await;
+        crate::metrics::record_agent_folder_batch("failed", file_count, batch_start.elapsed());
     }
 
     (ok_count, fail_count)

src/main.rs

@@ -7,6 +7,7 @@ mod i18n;
 mod jobs;
 mod lastfm;
 mod media_paths;
+mod metrics;
 mod music;
 mod oidc;
 mod player;
@@ -139,12 +140,41 @@ async fn logout_handler(session: Session) -> cot::Result<cot::response::Response
     Ok(auth::redirect("/login"))
 }
 
+async fn metrics_handler(
+    config: Arc<AppConfig>,
+    pool: Arc<tokio::sync::OnceCell<sqlx::PgPool>>,
+) -> cot::Result<cot::http::Response<Body>> {
+    if config.database_url.is_empty() {
+        return Ok(cot::http::Response::builder()
+            .status(cot::http::StatusCode::SERVICE_UNAVAILABLE)
+            .header(cot::http::header::CONTENT_TYPE, "text/plain; version=0.0.4")
+            .body(Body::fixed("furumusic_metrics_unavailable 1\n"))
+            .expect("valid response"));
+    }
+    let pg_pool = pool
+        .get_or_init(|| async {
+            sqlx::postgres::PgPoolOptions::new()
+                .max_connections(2)
+                .connect(&config.database_url)
+                .await
+                .expect("metrics pool")
+        })
+        .await;
+    let body = metrics::render(pg_pool, &config).await;
+    Ok(cot::http::Response::builder()
+        .status(cot::http::StatusCode::OK)
+        .header(cot::http::header::CONTENT_TYPE, "text/plain; version=0.0.4")
+        .body(Body::fixed(body))
+        .expect("valid response"))
+}
+
 // ---------------------------------------------------------------------------
 // App
 // ---------------------------------------------------------------------------
 
 struct FuruApp {
     config: Arc<AppConfig>,
+    pool: Arc<tokio::sync::OnceCell<sqlx::PgPool>>,
 }
 
 impl App for FuruApp {
@@ -171,6 +201,19 @@ impl App for FuruApp {
                 },
                 "index",
             ),
+            Route::with_handler_and_name(
+                "/metrics",
+                get({
+                    let config = Arc::clone(&self.config);
+                    let pool = Arc::clone(&self.pool);
+                    move || {
+                        let config = Arc::clone(&config);
+                        let pool = Arc::clone(&pool);
+                        async move { metrics_handler(config, pool).await }
+                    }
+                }),
+                "metrics",
+            ),
             Route::with_handler_and_name(
                 "/login",
                 get({
@@ -200,6 +243,11 @@ impl App for FuruApp {
                             let data = match result {
                                 FormResult::Ok(data) => data,
                                 FormResult::ValidationError(_) => {
+                                    metrics::record_auth_attempt(
+                                        "password",
+                                        "failure",
+                                        "validation_error",
+                                    );
                                     let msg = i18n.t.login_invalid.to_owned();
                                     return login_page_handler(i18n, &config, db, msg)
                                         .await?
@@ -216,6 +264,10 @@ impl App for FuruApp {
                                         PasswordVerificationResult::Ok
                                         | PasswordVerificationResult::OkObsolete(_) => {
                                             auth::login(&session, user.id_val()).await?;
+                                            metrics::record_auth_attempt(
+                                                "password", "success", "ok",
+                                            );
+                                            metrics::record_session_created("password");
                                             return Ok(auth::redirect("/"));
                                         }
                                         PasswordVerificationResult::Invalid => {}
@@ -223,6 +275,11 @@ impl App for FuruApp {
                                 }
                             }
 
+                            metrics::record_auth_attempt(
+                                "password",
+                                "failure",
+                                "bad_credentials",
+                            );
                             let msg = i18n.t.login_invalid.to_owned();
                             login_page_handler(i18n, &config, db, msg)
                                 .await?
@@ -332,6 +389,7 @@ impl Project for FuruProject {
         context: &cot::project::MiddlewareContext,
     ) -> cot::project::RootHandler {
         handler
+            .middleware(metrics::MetricsLayer)
             .middleware(StaticFilesMiddleware::from_context(context))
             .middleware(SessionMiddleware::from_context(context))
             .build()
@@ -361,6 +419,7 @@ impl Project for FuruProject {
         apps.register_with_views(
             FuruApp {
                 config: Arc::clone(&self.app_config),
+                pool: Arc::new(tokio::sync::OnceCell::new()),
             },
             "",
         );

src/metrics.rs

@@ -0,0 +1,843 @@
+use std::collections::{BTreeMap, HashMap};
+use std::future::Future;
+use std::path::Path;
+use std::pin::Pin;
+use std::sync::{LazyLock, Mutex};
+use std::task::{Context, Poll};
+use std::time::{Duration, Instant};
+
+use cot::http::header::CONTENT_LENGTH;
+use cot::http::Method;
+use cot::request::Request;
+use cot::response::Response;
+use cot::Error;
+use sqlx::PgPool;
+use tower::{Layer, Service};
+
+use crate::config::AppConfig;
+
+const HTTP_BUCKETS: &[f64] = &[
+    0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10.0,
+];
+const JOB_BUCKETS: &[f64] = &[0.1, 0.5, 1.0, 2.5, 5.0, 10.0, 30.0, 60.0, 300.0, 600.0];
+const FILE_BUCKETS: &[f64] = &[
+    0.001, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 15.0, 60.0,
+];
+
+static REGISTRY: LazyLock<Registry> = LazyLock::new(Registry::default);
+static ACTIVE_USERS: LazyLock<Mutex<HashMap<i64, Instant>>> =
+    LazyLock::new(|| Mutex::new(HashMap::new()));
+
+#[derive(Default)]
+struct Registry {
+    counters: Mutex<BTreeMap<MetricKey, f64>>,
+    gauges: Mutex<BTreeMap<MetricKey, f64>>,
+    histograms: Mutex<BTreeMap<MetricKey, HistogramState>>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
+struct MetricKey {
+    name: &'static str,
+    labels: Vec<(&'static str, String)>,
+}
+
+#[derive(Debug, Clone)]
+struct HistogramState {
+    buckets: Vec<f64>,
+    counts: Vec<u64>,
+    sum: f64,
+    count: u64,
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct MetricsLayer;
+
+#[derive(Debug, Clone)]
+pub struct MetricsService<S> {
+    inner: S,
+}
+
+impl<S> Layer<S> for MetricsLayer {
+    type Service = MetricsService<S>;
+
+    fn layer(&self, inner: S) -> Self::Service {
+        MetricsService { inner }
+    }
+}
+
+impl<S> Service<Request> for MetricsService<S>
+where
+    S: Service<Request, Response = Response, Error = Error> + Send + 'static,
+    S::Future: Send + 'static,
+{
+    type Response = Response;
+    type Error = Error;
+    type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>;
+
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.inner.poll_ready(cx)
+    }
+
+    fn call(&mut self, request: Request) -> Self::Future {
+        let method = request.method().clone();
+        let route = normalize_route(request.uri().path());
+        let request_bytes = request
+            .headers()
+            .get(CONTENT_LENGTH)
+            .and_then(|value| value.to_str().ok())
+            .and_then(|value| value.parse::<f64>().ok())
+            .unwrap_or(0.0);
+        let labels = http_labels(&method, &route, "in_flight");
+        REGISTRY.inc_gauge("furumusic_http_in_flight_requests", labels, 1.0);
+        REGISTRY.inc_counter(
+            "furumusic_http_request_body_bytes_total",
+            vec![
+                ("method", method.as_str().to_owned()),
+                ("route", route.clone()),
+            ],
+            request_bytes,
+        );
+
+        let start = Instant::now();
+        let fut = self.inner.call(request);
+        Box::pin(async move {
+            let result = fut.await;
+            let elapsed = start.elapsed().as_secs_f64();
+            REGISTRY.inc_gauge(
+                "furumusic_http_in_flight_requests",
+                http_labels(&method, &route, "in_flight"),
+                -1.0,
+            );
+
+            match result {
+                Ok(response) => {
+                    let status = response.status().as_u16().to_string();
+                    let labels = http_labels(&method, &route, &status);
+                    REGISTRY.inc_counter("furumusic_http_requests_total", labels.clone(), 1.0);
+                    REGISTRY.observe_histogram(
+                        "furumusic_http_request_duration_seconds",
+                        labels,
+                        elapsed,
+                        HTTP_BUCKETS,
+                    );
+                    if let Some(length) = response
+                        .headers()
+                        .get(CONTENT_LENGTH)
+                        .and_then(|value| value.to_str().ok())
+                        .and_then(|value| value.parse::<f64>().ok())
+                    {
+                        REGISTRY.inc_counter(
+                            "furumusic_http_response_body_bytes_total",
+                            vec![
+                                ("method", method.as_str().to_owned()),
+                                ("route", route.clone()),
+                                ("status", status),
+                            ],
+                            length,
+                        );
+                    }
+                    Ok(response)
+                }
+                Err(error) => {
+                    let labels = http_labels(&method, &route, "500");
+                    REGISTRY.inc_counter("furumusic_http_requests_total", labels.clone(), 1.0);
+                    REGISTRY.observe_histogram(
+                        "furumusic_http_request_duration_seconds",
+                        labels,
+                        elapsed,
+                        HTTP_BUCKETS,
+                    );
+                    Err(error)
+                }
+            }
+        })
+    }
+}
+
+pub fn record_active_user(user_id: i64) {
+    let mut users = ACTIVE_USERS.lock().expect("active user lock");
+    users.insert(user_id, Instant::now());
+}
+
+pub fn record_auth_attempt(method: &'static str, outcome: &'static str, reason: &'static str) {
+    REGISTRY.inc_counter(
+        "furumusic_auth_login_attempts_total",
+        vec![
+            ("method", method.to_owned()),
+            ("outcome", outcome.to_owned()),
+            ("reason", reason.to_owned()),
+        ],
+        1.0,
+    );
+}
+
+pub fn record_session_created(method: &'static str) {
+    REGISTRY.inc_counter(
+        "furumusic_auth_sessions_created_total",
+        vec![("method", method.to_owned())],
+        1.0,
+    );
+}
+
+pub fn record_authorization_denied(kind: &'static str) {
+    REGISTRY.inc_counter(
+        "furumusic_auth_denied_total",
+        vec![("kind", kind.to_owned())],
+        1.0,
+    );
+}
+
+pub fn record_play_history(duration_listened: Option<i32>, completed: bool) {
+    REGISTRY.inc_counter(
+        "furumusic_listens_total",
+        vec![(
+            "completed",
+            if completed { "true" } else { "false" }.to_owned(),
+        )],
+        1.0,
+    );
+    if let Some(seconds) = duration_listened {
+        REGISTRY.inc_counter(
+            "furumusic_listened_seconds_total",
+            Vec::new(),
+            seconds.max(0) as f64,
+        );
+    }
+}
+
+pub fn record_stream_request(range: bool, bytes: u64) {
+    REGISTRY.inc_counter(
+        "furumusic_stream_requests_total",
+        vec![("range", if range { "true" } else { "false" }.to_owned())],
+        1.0,
+    );
+    REGISTRY.inc_counter("furumusic_stream_bytes_total", Vec::new(), bytes as f64);
+}
+
+pub fn record_agent_discover_run(outcome: &'static str, duration: Duration) {
+    REGISTRY.inc_counter(
+        "furumusic_agent_discover_runs_total",
+        vec![("outcome", outcome.to_owned())],
+        1.0,
+    );
+    REGISTRY.observe_histogram(
+        "furumusic_agent_discover_duration_seconds",
+        vec![("outcome", outcome.to_owned())],
+        duration.as_secs_f64(),
+        JOB_BUCKETS,
+    );
+}
+
+pub fn record_agent_discover_files(seen: u64, queued: u64, skipped_hash: u64, skipped_existing: u64) {
+    REGISTRY.inc_counter("furumusic_agent_discover_files_seen_total", Vec::new(), seen as f64);
+    REGISTRY.inc_counter(
+        "furumusic_agent_discover_files_queued_total",
+        Vec::new(),
+        queued as f64,
+    );
+    REGISTRY.inc_counter(
+        "furumusic_agent_discover_files_skipped_total",
+        vec![("reason", "hash_known".to_owned())],
+        skipped_hash as f64,
+    );
+    REGISTRY.inc_counter(
+        "furumusic_agent_discover_files_skipped_total",
+        vec![("reason", "already_queued".to_owned())],
+        skipped_existing as f64,
+    );
+}
+
+pub fn record_agent_file_hash(duration: Duration, bytes: i64, outcome: &'static str) {
+    REGISTRY.observe_histogram(
+        "furumusic_agent_discover_hash_duration_seconds",
+        vec![("outcome", outcome.to_owned())],
+        duration.as_secs_f64(),
+        FILE_BUCKETS,
+    );
+    if bytes > 0 {
+        REGISTRY.inc_counter(
+            "furumusic_agent_discover_file_bytes_total",
+            vec![("outcome", outcome.to_owned())],
+            bytes as f64,
+        );
+    }
+}
+
+pub fn record_agent_metadata(duration: Duration, outcome: &'static str) {
+    REGISTRY.observe_histogram(
+        "furumusic_agent_discover_metadata_duration_seconds",
+        vec![("outcome", outcome.to_owned())],
+        duration.as_secs_f64(),
+        FILE_BUCKETS,
+    );
+}
+
+pub fn record_agent_folder_batch(outcome: &'static str, size: usize, duration: Duration) {
+    REGISTRY.inc_counter(
+        "furumusic_agent_folder_batches_total",
+        vec![("outcome", outcome.to_owned())],
+        1.0,
+    );
+    REGISTRY.observe_histogram(
+        "furumusic_agent_folder_batch_duration_seconds",
+        vec![("outcome", outcome.to_owned())],
+        duration.as_secs_f64(),
+        JOB_BUCKETS,
+    );
+    REGISTRY.observe_histogram(
+        "furumusic_agent_folder_batch_size",
+        vec![("outcome", outcome.to_owned())],
+        size as f64,
+        &[1.0, 2.0, 5.0, 10.0, 20.0, 50.0, 100.0],
+    );
+}
+
+pub fn record_agent_file_processed(outcome: &'static str, decision: &'static str) {
+    REGISTRY.inc_counter(
+        "furumusic_agent_files_processed_total",
+        vec![
+            ("outcome", outcome.to_owned()),
+            ("decision", decision.to_owned()),
+        ],
+        1.0,
+    );
+}
+
+pub fn record_agent_failed(stage: &'static str) {
+    REGISTRY.inc_counter(
+        "furumusic_agent_failed_total",
+        vec![("stage", stage.to_owned())],
+        1.0,
+    );
+}
+
+pub fn observe_agent_confidence(confidence: f64) {
+    REGISTRY.observe_histogram(
+        "furumusic_agent_confidence",
+        Vec::new(),
+        confidence,
+        &[0.1, 0.2, 0.4, 0.6, 0.75, 0.85, 0.95, 1.0],
+    );
+}
+
+pub fn record_agent_llm(
+    model: &str,
+    outcome: &'static str,
+    duration: Duration,
+    prompt_tokens: u64,
+    completion_tokens: u64,
+    batch_size: usize,
+    estimated_tokens: Option<u64>,
+) {
+    let model = normalize_model_label(model);
+    REGISTRY.inc_counter(
+        "furumusic_agent_llm_requests_total",
+        vec![
+            ("model", model.clone()),
+            ("outcome", outcome.to_owned()),
+        ],
+        1.0,
+    );
+    REGISTRY.observe_histogram(
+        "furumusic_agent_llm_duration_seconds",
+        vec![
+            ("model", model.clone()),
+            ("outcome", outcome.to_owned()),
+        ],
+        duration.as_secs_f64(),
+        JOB_BUCKETS,
+    );
+    REGISTRY.inc_counter(
+        "furumusic_agent_llm_tokens_total",
+        vec![("model", model.clone()), ("type", "prompt".to_owned())],
+        prompt_tokens as f64,
+    );
+    REGISTRY.inc_counter(
+        "furumusic_agent_llm_tokens_total",
+        vec![
+            ("model", model.clone()),
+            ("type", "completion".to_owned()),
+        ],
+        completion_tokens as f64,
+    );
+    REGISTRY.observe_histogram(
+        "furumusic_agent_llm_batch_size",
+        vec![("model", model.clone())],
+        batch_size as f64,
+        &[1.0, 2.0, 5.0, 10.0, 20.0, 50.0, 100.0],
+    );
+    if let Some(estimated) = estimated_tokens {
+        REGISTRY.observe_histogram(
+            "furumusic_agent_llm_context_estimated_tokens",
+            vec![("model", model)],
+            estimated as f64,
+            &[512.0, 1024.0, 2048.0, 4096.0, 8192.0, 16384.0, 32768.0],
+        );
+    }
+}
+
+pub fn record_agent_llm_split(reason: &'static str) {
+    REGISTRY.inc_counter(
+        "furumusic_agent_llm_batch_splits_total",
+        vec![("reason", reason.to_owned())],
+        1.0,
+    );
+}
+
+pub fn record_agent_llm_parse_failure(model: &str) {
+    REGISTRY.inc_counter(
+        "furumusic_agent_llm_parse_failures_total",
+        vec![("model", normalize_model_label(model))],
+        1.0,
+    );
+}
+
+pub fn record_agent_rag(kind: &'static str, outcome: &'static str, duration: Duration, results: usize) {
+    REGISTRY.inc_counter(
+        "furumusic_agent_rag_queries_total",
+        vec![("kind", kind.to_owned()), ("outcome", outcome.to_owned())],
+        1.0,
+    );
+    REGISTRY.observe_histogram(
+        "furumusic_agent_rag_duration_seconds",
+        vec![("kind", kind.to_owned()), ("outcome", outcome.to_owned())],
+        duration.as_secs_f64(),
+        FILE_BUCKETS,
+    );
+    REGISTRY.observe_histogram(
+        "furumusic_agent_rag_results",
+        vec![("kind", kind.to_owned())],
+        results as f64,
+        &[0.0, 1.0, 2.0, 5.0, 10.0],
+    );
+}
+
+pub fn record_agent_cover_lookup(source: &'static str, outcome: &'static str, bytes: usize) {
+    REGISTRY.inc_counter(
+        "furumusic_agent_cover_lookup_total",
+        vec![("source", source.to_owned()), ("outcome", outcome.to_owned())],
+        1.0,
+    );
+    REGISTRY.inc_counter(
+        "furumusic_agent_cover_bytes_total",
+        vec![("source", source.to_owned())],
+        bytes as f64,
+    );
+}
+
+pub fn record_agent_cover_variant(variant: &'static str, outcome: &'static str, duration: Duration) {
+    REGISTRY.inc_counter(
+        "furumusic_agent_cover_variant_generation_total",
+        vec![
+            ("variant", variant.to_owned()),
+            ("outcome", outcome.to_owned()),
+        ],
+        1.0,
+    );
+    REGISTRY.observe_histogram(
+        "furumusic_agent_cover_variant_duration_seconds",
+        vec![
+            ("variant", variant.to_owned()),
+            ("outcome", outcome.to_owned()),
+        ],
+        duration.as_secs_f64(),
+        FILE_BUCKETS,
+    );
+}
+
+pub fn record_scheduler_job(job: &str, trigger: &str, outcome: &'static str, duration_ms: i64) {
+    let labels = vec![
+        ("job", job.to_owned()),
+        ("trigger", trigger.to_owned()),
+        ("outcome", outcome.to_owned()),
+    ];
+    REGISTRY.inc_counter("furumusic_scheduler_job_runs_total", labels.clone(), 1.0);
+    REGISTRY.observe_histogram(
+        "furumusic_scheduler_job_duration_seconds",
+        labels,
+        (duration_ms.max(0) as f64) / 1000.0,
+        JOB_BUCKETS,
+    );
+}
+
+pub fn record_torrent_download(outcome: &'static str, selected_bytes: u64, duration: Duration) {
+    REGISTRY.inc_counter(
+        "furumusic_torrent_downloads_total",
+        vec![("outcome", outcome.to_owned())],
+        1.0,
+    );
+    REGISTRY.inc_counter(
+        "furumusic_torrent_selected_bytes_total",
+        vec![("outcome", outcome.to_owned())],
+        selected_bytes as f64,
+    );
+    REGISTRY.observe_histogram(
+        "furumusic_torrent_download_duration_seconds",
+        vec![("outcome", outcome.to_owned())],
+        duration.as_secs_f64(),
+        JOB_BUCKETS,
+    );
+}
+
+pub async fn render(pool: &PgPool, config: &AppConfig) -> String {
+    let mut out = String::new();
+    emit_static_gauge(&mut out, "furumusic_build_info", &[("version", env!("CARGO_PKG_VERSION"))], 1.0);
+    render_active_users(&mut out);
+    render_storage(&mut out, config);
+    render_db_metrics(&mut out, pool).await;
+    out.push_str(&REGISTRY.render());
+    out
+}
+
+fn render_active_users(out: &mut String) {
+    let mut users = ACTIVE_USERS.lock().expect("active user lock");
+    let now = Instant::now();
+    users.retain(|_, seen| now.duration_since(*seen) <= Duration::from_secs(3600));
+    for (window, seconds) in [("5m", 300), ("15m", 900), ("1h", 3600)] {
+        let count = users
+            .values()
+            .filter(|seen| now.duration_since(**seen) <= Duration::from_secs(seconds))
+            .count();
+        emit_static_gauge(
+            out,
+            "furumusic_active_users",
+            &[("window", window)],
+            count as f64,
+        );
+    }
+}
+
+fn render_storage(out: &mut String, config: &AppConfig) {
+    for (kind, path) in [
+        ("inbox", config.agent_inbox_dir.as_str()),
+        ("library", config.agent_storage_dir.as_str()),
+    ] {
+        if let Some(usage) = disk_usage(Path::new(path.trim())) {
+            emit_static_gauge(
+                out,
+                "furumusic_storage_free_bytes",
+                &[("path_kind", kind)],
+                usage.free_bytes as f64,
+            );
+            emit_static_gauge(
+                out,
+                "furumusic_storage_total_bytes",
+                &[("path_kind", kind)],
+                usage.total_bytes as f64,
+            );
+        }
+    }
+}
+
+async fn render_db_metrics(out: &mut String, pool: &PgPool) {
+    render_group_counts(out, pool, "furumusic_users_total", "SELECT role::text AS label, COUNT(*) AS count FROM furumusic__user GROUP BY role", "role").await;
+    render_single_count(out, pool, "furumusic_library_tracks_total", "SELECT COUNT(*) FROM furumusic__track").await;
+    render_single_count(out, pool, "furumusic_library_releases_total", "SELECT COUNT(*) FROM furumusic__release").await;
+    render_single_count(out, pool, "furumusic_library_artists_total", "SELECT COUNT(*) FROM furumusic__artist").await;
+    render_single_count(out, pool, "furumusic_library_playlists_total", "SELECT COUNT(*) FROM furumusic__playlist").await;
+    render_group_counts(out, pool, "furumusic_media_files_total", "SELECT file_type::text AS label, COUNT(*) AS count FROM furumusic__media_file GROUP BY file_type", "type").await;
+    render_group_sums(out, pool, "furumusic_media_file_bytes_total", "SELECT file_type::text AS label, COALESCE(SUM(file_size_bytes), 0)::bigint AS value FROM furumusic__media_file GROUP BY file_type", "type").await;
+    render_group_counts(out, pool, "furumusic_agent_reviews_total", "SELECT status::text AS label, COUNT(*) AS count FROM furumusic__pending_review GROUP BY status", "status").await;
+    render_group_counts(out, pool, "furumusic_agent_queue_depth", "SELECT status::text AS label, COUNT(*) AS count FROM furumusic__pending_review GROUP BY status", "status").await;
+    render_group_counts(out, pool, "furumusic_scheduler_job_running", "SELECT job_name::text AS label, COUNT(*) AS count FROM furumusic__job_run WHERE status = 'running' GROUP BY job_name", "job").await;
+    render_group_sums(out, pool, "furumusic_scheduler_job_enabled", "SELECT name::text AS label, (CASE WHEN enabled THEN 1 ELSE 0 END)::bigint AS value FROM furumusic__scheduled_job", "job").await;
+    render_group_counts(out, pool, "furumusic_torrent_sessions_total", "SELECT status::text AS label, COUNT(*) AS count FROM furumusic__torrent_session GROUP BY status", "status").await;
+    render_single_count(out, pool, "furumusic_play_history_total", "SELECT COUNT(*) FROM furumusic__play_history").await;
+}
+
+async fn render_single_count(out: &mut String, pool: &PgPool, metric: &'static str, sql: &str) {
+    if let Ok(value) = sqlx::query_scalar::<_, i64>(sql).fetch_one(pool).await {
+        emit_static_gauge(out, metric, &[], value as f64);
+    }
+}
+
+async fn render_group_counts(
+    out: &mut String,
+    pool: &PgPool,
+    metric: &'static str,
+    sql: &str,
+    label_name: &'static str,
+) {
+    if let Ok(rows) = sqlx::query_as::<_, (String, i64)>(sql).fetch_all(pool).await {
+        for (label, count) in rows {
+            emit_static_gauge(out, metric, &[(label_name, label.as_str())], count as f64);
+        }
+    }
+}
+
+async fn render_group_sums(
+    out: &mut String,
+    pool: &PgPool,
+    metric: &'static str,
+    sql: &str,
+    label_name: &'static str,
+) {
+    if let Ok(rows) = sqlx::query_as::<_, (String, i64)>(sql).fetch_all(pool).await {
+        for (label, value) in rows {
+            emit_static_gauge(out, metric, &[(label_name, label.as_str())], value as f64);
+        }
+    }
+}
+
+impl Registry {
+    fn inc_counter(&self, name: &'static str, labels: Vec<(&'static str, String)>, value: f64) {
+        if value <= 0.0 {
+            return;
+        }
+        let mut counters = self.counters.lock().expect("counter lock");
+        *counters.entry(MetricKey::new(name, labels)).or_default() += value;
+    }
+
+    fn inc_gauge(&self, name: &'static str, labels: Vec<(&'static str, String)>, value: f64) {
+        let mut gauges = self.gauges.lock().expect("gauge lock");
+        *gauges.entry(MetricKey::new(name, labels)).or_default() += value;
+    }
+
+    fn observe_histogram(
+        &self,
+        name: &'static str,
+        labels: Vec<(&'static str, String)>,
+        value: f64,
+        buckets: &[f64],
+    ) {
+        let mut histograms = self.histograms.lock().expect("histogram lock");
+        let state = histograms
+            .entry(MetricKey::new(name, labels))
+            .or_insert_with(|| HistogramState {
+                buckets: buckets.to_vec(),
+                counts: vec![0; buckets.len()],
+                sum: 0.0,
+                count: 0,
+            });
+        for (index, bucket) in state.buckets.iter().enumerate() {
+            if value <= *bucket {
+                state.counts[index] += 1;
+            }
+        }
+        state.sum += value;
+        state.count += 1;
+    }
+
+    fn render(&self) -> String {
+        let mut out = String::new();
+        for (key, value) in self.counters.lock().expect("counter lock").iter() {
+            emit_type(&mut out, key.name, "counter");
+            emit_metric(&mut out, key.name, &key.labels, *value);
+        }
+        for (key, value) in self.gauges.lock().expect("gauge lock").iter() {
+            emit_type(&mut out, key.name, "gauge");
+            emit_metric(&mut out, key.name, &key.labels, (*value).max(0.0));
+        }
+        for (key, state) in self.histograms.lock().expect("histogram lock").iter() {
+            emit_type(&mut out, key.name, "histogram");
+            for (bucket, count) in state.buckets.iter().zip(state.counts.iter()) {
+                let mut labels = key.labels.clone();
+                labels.push(("le", bucket.to_string()));
+                emit_metric(&mut out, &format!("{}_bucket", key.name), &labels, *count as f64);
+            }
+            let mut inf_labels = key.labels.clone();
+            inf_labels.push(("le", "+Inf".to_owned()));
+            emit_metric(
+                &mut out,
+                &format!("{}_bucket", key.name),
+                &inf_labels,
+                state.count as f64,
+            );
+            emit_metric(
+                &mut out,
+                &format!("{}_sum", key.name),
+                &key.labels,
+                state.sum,
+            );
+            emit_metric(
+                &mut out,
+                &format!("{}_count", key.name),
+                &key.labels,
+                state.count as f64,
+            );
+        }
+        out
+    }
+}
+
+impl MetricKey {
+    fn new(name: &'static str, mut labels: Vec<(&'static str, String)>) -> Self {
+        labels.sort_by(|a, b| a.0.cmp(b.0));
+        Self { name, labels }
+    }
+}
+
+fn http_labels(method: &Method, route: &str, status: &str) -> Vec<(&'static str, String)> {
+    vec![
+        ("method", method.as_str().to_owned()),
+        ("route", route.to_owned()),
+        ("status", status.to_owned()),
+    ]
+}
+
+fn normalize_route(path: &str) -> String {
+    let mut route = String::with_capacity(path.len());
+    for segment in path.split('/') {
+        if segment.is_empty() {
+            continue;
+        }
+        route.push('/');
+        if segment.parse::<i64>().is_ok() || looks_like_uuid(segment) {
+            route.push_str("{id}");
+        } else {
+            route.push_str(segment);
+        }
+    }
+    if route.is_empty() {
+        "/".to_owned()
+    } else {
+        route
+    }
+}
+
+fn looks_like_uuid(value: &str) -> bool {
+    value.len() == 36
+        && value
+            .chars()
+            .all(|ch| ch.is_ascii_hexdigit() || ch == '-')
+}
+
+fn normalize_model_label(value: &str) -> String {
+    let trimmed = value.trim();
+    if trimmed.is_empty() {
+        "unknown".to_owned()
+    } else {
+        trimmed.chars().take(80).collect()
+    }
+}
+
+fn emit_static_gauge(out: &mut String, name: &str, labels: &[(&str, &str)], value: f64) {
+    emit_type(out, name, "gauge");
+    let labels = labels
+        .iter()
+        .map(|(key, value)| (*key, (*value).to_owned()))
+        .collect::<Vec<_>>();
+    emit_metric(out, name, &labels, value);
+}
+
+fn emit_type(out: &mut String, name: &str, metric_type: &str) {
+    let _ = (out, name, metric_type);
+}
+
+fn emit_metric(out: &mut String, name: &str, labels: &[(&str, String)], value: f64) {
+    out.push_str(name);
+    if !labels.is_empty() {
+        out.push('{');
+        for (index, (key, value)) in labels.iter().enumerate() {
+            if index > 0 {
+                out.push(',');
+            }
+            out.push_str(key);
+            out.push_str("=\"");
+            escape_label(out, value);
+            out.push('"');
+        }
+        out.push('}');
+    }
+    out.push(' ');
+    out.push_str(&format!("{value:.6}"));
+    out.push('\n');
+}
+
+fn escape_label(out: &mut String, value: &str) {
+    for ch in value.chars() {
+        match ch {
+            '\\' => out.push_str("\\\\"),
+            '"' => out.push_str("\\\""),
+            '\n' => out.push_str("\\n"),
+            _ => out.push(ch),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+struct DiskUsage {
+    free_bytes: u64,
+    total_bytes: u64,
+}
+
+#[cfg(windows)]
+fn disk_usage(path: &Path) -> Option<DiskUsage> {
+    use std::os::windows::ffi::OsStrExt;
+
+    #[link(name = "kernel32")]
+    unsafe extern "system" {
+        fn GetDiskFreeSpaceExW(
+            lpDirectoryName: *const u16,
+            lpFreeBytesAvailableToCaller: *mut u64,
+            lpTotalNumberOfBytes: *mut u64,
+            lpTotalNumberOfFreeBytes: *mut u64,
+        ) -> i32;
+    }
+
+    let mut wide: Vec<u16> = path.as_os_str().encode_wide().collect();
+    wide.push(0);
+    let mut free_available = 0_u64;
+    let mut total = 0_u64;
+    let mut total_free = 0_u64;
+    let ok = unsafe {
+        GetDiskFreeSpaceExW(
+            wide.as_ptr(),
+            &mut free_available,
+            &mut total,
+            &mut total_free,
+        )
+    };
+    (ok != 0).then_some(DiskUsage {
+        free_bytes: free_available,
+        total_bytes: total,
+    })
+}
+
+#[cfg(any(target_os = "linux", target_os = "android"))]
+fn disk_usage(path: &Path) -> Option<DiskUsage> {
+    use std::ffi::CString;
+    use std::os::unix::ffi::OsStrExt;
+
+    #[repr(C)]
+    struct Statvfs {
+        f_bsize: std::ffi::c_ulong,
+        f_frsize: std::ffi::c_ulong,
+        f_blocks: std::ffi::c_ulong,
+        f_bfree: std::ffi::c_ulong,
+        f_bavail: std::ffi::c_ulong,
+        f_files: std::ffi::c_ulong,
+        f_ffree: std::ffi::c_ulong,
+        f_favail: std::ffi::c_ulong,
+        f_fsid: std::ffi::c_ulong,
+        f_flag: std::ffi::c_ulong,
+        f_namemax: std::ffi::c_ulong,
+        __f_spare: [std::ffi::c_int; 6],
+    }
+
+    unsafe extern "C" {
+        fn statvfs(path: *const std::ffi::c_char, buf: *mut Statvfs) -> std::ffi::c_int;
+    }
+
+    let c_path = CString::new(path.as_os_str().as_bytes()).ok()?;
+    let mut stat = std::mem::MaybeUninit::<Statvfs>::uninit();
+    let ok = unsafe { statvfs(c_path.as_ptr(), stat.as_mut_ptr()) };
+    if ok != 0 {
+        return None;
+    }
+    let stat = unsafe { stat.assume_init() };
+    let fragment_size = if stat.f_frsize > 0 {
+        stat.f_frsize as u64
+    } else {
+        stat.f_bsize as u64
+    };
+    Some(DiskUsage {
+        free_bytes: stat.f_bavail as u64 * fragment_size,
+        total_bytes: stat.f_blocks as u64 * fragment_size,
+    })
+}
+
+#[cfg(not(any(windows, target_os = "linux", target_os = "android")))]
+fn disk_usage(_path: &Path) -> Option<DiskUsage> {
+    None
+}

src/oidc.rs

@@ -172,6 +172,7 @@ pub async fn oidc_start_handler(
         || config.oidc_client_secret.is_empty()
     {
         tracing::warn!("OIDC start requested but SSO is not configured");
+        crate::metrics::record_auth_attempt("oidc", "failure", "not_configured");
         return redirect_login_with_error(i18n.t.login_sso_disabled);
     }
 
@@ -180,6 +181,7 @@ pub async fn oidc_start_handler(
         Ok(c) => c,
         Err(e) => {
             tracing::error!("OIDC provider error: {e}");
+            crate::metrics::record_auth_attempt("oidc", "failure", "provider_error");
             return redirect_login_with_error(i18n.t.login_oidc_error);
         }
     };
@@ -276,19 +278,23 @@ pub async fn oidc_callback_handler(
     // Validate CSRF state.
     let Some(saved_csrf) = saved_csrf else {
         tracing::warn!("OIDC callback: no CSRF state in session");
+        crate::metrics::record_auth_attempt("oidc", "failure", "missing_state");
         return redirect_login_with_error(i18n.t.login_oidc_error);
     };
     if query.state != saved_csrf {
         tracing::warn!("OIDC callback: CSRF state mismatch");
+        crate::metrics::record_auth_attempt("oidc", "failure", "csrf");
         return redirect_login_with_error(i18n.t.login_oidc_error);
     }
 
     let Some(nonce_str) = saved_nonce else {
         tracing::warn!("OIDC callback: no nonce in session");
+        crate::metrics::record_auth_attempt("oidc", "failure", "missing_nonce");
         return redirect_login_with_error(i18n.t.login_oidc_error);
     };
     let Some(pkce_str) = saved_pkce else {
         tracing::warn!("OIDC callback: no PKCE verifier in session");
+        crate::metrics::record_auth_attempt("oidc", "failure", "missing_pkce");
         return redirect_login_with_error(i18n.t.login_oidc_error);
     };
 
@@ -300,6 +306,7 @@ pub async fn oidc_callback_handler(
         Ok(c) => c,
         Err(e) => {
             tracing::error!("OIDC provider error during callback: {e}");
+            crate::metrics::record_auth_attempt("oidc", "failure", "provider_error");
             return redirect_login_with_error(i18n.t.login_oidc_error);
         }
     };
@@ -318,6 +325,7 @@ pub async fn oidc_callback_handler(
         Ok(req) => req,
         Err(e) => {
             tracing::error!("OIDC token endpoint not configured: {e}");
+            crate::metrics::record_auth_attempt("oidc", "failure", "token_config");
             return redirect_login_with_error(i18n.t.login_oidc_error);
         }
     };
@@ -330,6 +338,7 @@ pub async fn oidc_callback_handler(
         Ok(t) => t,
         Err(e) => {
             tracing::error!("OIDC token exchange failed: {e}");
+            crate::metrics::record_auth_attempt("oidc", "failure", "token_exchange");
             return redirect_login_with_error(i18n.t.login_oidc_error);
         }
     };
@@ -340,6 +349,7 @@ pub async fn oidc_callback_handler(
         Some(t) => t,
         None => {
             tracing::error!("OIDC response missing ID token");
+            crate::metrics::record_auth_attempt("oidc", "failure", "missing_id_token");
             return redirect_login_with_error(i18n.t.login_oidc_error);
         }
     };
@@ -348,6 +358,7 @@ pub async fn oidc_callback_handler(
         Ok(c) => c,
         Err(e) => {
             tracing::error!("OIDC ID token verification failed: {e}");
+            crate::metrics::record_auth_attempt("oidc", "failure", "id_token_verify");
             return redirect_login_with_error(i18n.t.login_oidc_error);
         }
     };
@@ -395,6 +406,7 @@ pub async fn oidc_callback_handler(
             config.oidc_user_groups,
             config.oidc_admin_groups,
         );
+        crate::metrics::record_auth_attempt("oidc", "failure", "not_in_group");
         return redirect_login_with_error(i18n.t.login_access_denied);
     }
 
@@ -413,12 +425,15 @@ pub async fn oidc_callback_handler(
         Ok(u) => u,
         Err(e) => {
             tracing::error!("OIDC user provisioning failed: {e}");
+            crate::metrics::record_auth_attempt("oidc", "failure", "provisioning");
             return redirect_login_with_error(i18n.t.login_oidc_error);
         }
     };
 
     // Log the user in.
     auth::login(&session, user.id_val()).await?;
+    crate::metrics::record_auth_attempt("oidc", "success", "ok");
+    crate::metrics::record_session_created("oidc");
 
     // Clear OIDC session keys.
     let _: Option<String> = session

src/player/mod.rs

@@ -3571,6 +3571,7 @@ async fn stream_handler(
             let chunk_size = end - start + 1;
 
             let data = read_file_range(&full_path, start, chunk_size).await?;
+            crate::metrics::record_stream_request(true, chunk_size);
 
             let response = cot::http::Response::builder()
                 .status(StatusCode::PARTIAL_CONTENT)
@@ -3589,6 +3590,7 @@ async fn stream_handler(
     let data = tokio::fs::read(&full_path)
         .await
         .map_err(|e| cot::Error::internal(e.to_string()))?;
+    crate::metrics::record_stream_request(false, file_size);
 
     let response = cot::http::Response::builder()
         .status(StatusCode::OK)
@@ -4491,6 +4493,7 @@ async fn history_handler(
     .execute(pool)
     .await
     .map_err(|e| cot::Error::internal(e.to_string()))?;
+    crate::metrics::record_play_history(entry.duration_listened, entry.completed);
 
     if let Some(listened_seconds) = entry.duration_listened {
         let (config, _) = AppConfig::load_with_db(&db).await;

src/scheduler/mod.rs

@@ -200,6 +200,12 @@ impl JobRun {
         duration_ms: i64,
         log: &str,
     ) -> cot::db::Result<()> {
+        crate::metrics::record_scheduler_job(
+            self.job_name.as_str(),
+            self.trigger.as_str(),
+            "completed",
+            duration_ms,
+        );
         self.status = LimitedString::new("completed").unwrap();
         self.finished_at = Some(now_iso().to_string());
         self.duration_ms = Some(duration_ms);
@@ -214,6 +220,12 @@ impl JobRun {
         log: &str,
         error: &str,
     ) -> cot::db::Result<()> {
+        crate::metrics::record_scheduler_job(
+            self.job_name.as_str(),
+            self.trigger.as_str(),
+            "failed",
+            duration_ms,
+        );
         self.status = LimitedString::new("failed").unwrap();
         self.finished_at = Some(now_iso().to_string());
         self.duration_ms = Some(duration_ms);

src/torrents.rs

@@ -777,7 +777,7 @@ impl TorrentService {
 
         self.ensure_memory_job(pool, uploader_user_id, id).await?;
 
-        let (torrent_bytes, output_dir) = {
+        let (torrent_bytes, output_dir, selected_size) = {
             let mut jobs = self.jobs.lock().await;
             let job = jobs.get_mut(id).context("torrent job not found")?;
             if job.user_id != uploader_user_id {
@@ -800,7 +800,11 @@ impl TorrentService {
             job.error = None;
             job.completed_at = None;
             job.updated_at = now_string();
-            (job.torrent_bytes.clone(), job.output_dir.clone())
+            (
+                job.torrent_bytes.clone(),
+                job.output_dir.clone(),
+                job.selected_size(),
+            )
         };
 
         tokio::fs::create_dir_all(&output_dir).await?;
@@ -846,6 +850,7 @@ impl TorrentService {
         let service = Arc::clone(self);
         let pool = pool.clone();
         let id = id.to_string();
+        let download_start = std::time::Instant::now();
         tokio::spawn(async move {
             if let Err(err) = handle.wait_until_completed().await {
                 if service.is_paused(&id).await {
@@ -853,6 +858,11 @@ impl TorrentService {
                 }
                 service.stop_torrent(&handle).await;
                 service.fail_job(&pool, &id, err.to_string()).await;
+                crate::metrics::record_torrent_download(
+                    "failed",
+                    selected_size,
+                    download_start.elapsed(),
+                );
                 return;
             }
             service.stop_torrent(&handle).await;
@@ -861,6 +871,17 @@ impl TorrentService {
                 .await
             {
                 service.fail_job(&pool, &id, err.to_string()).await;
+                crate::metrics::record_torrent_download(
+                    "failed",
+                    selected_size,
+                    download_start.elapsed(),
+                );
+            } else {
+                crate::metrics::record_torrent_download(
+                    "completed",
+                    selected_size,
+                    download_start.elapsed(),
+                );
             }
         });