Add comprehensive logging with tracing, file rotation, and systemd integration

- Add tracing-appender and tracing-journald for production logging
- Add LoggingConfig with trace_sample_rate, json_output, journald options
- Expand init_logging() with file rotation, journald, and stderr layers
- Add sanitize_path() helper for PII protection in logs
- Instrument FUSE operations with #[instrument] and trace decision points
- Instrument gRPC handlers (10 methods) with span correlation
- Add spawn instrumentation for health monitor, indexer, watcher tasks
- Add broadcast lag handling (RecvError::Lagged) in event subscribers
- Fix webhook.rs expect() calls with proper error handling
- Add logging to patterns.rs, collections.rs, artwork.rs database ops
- Add Drop impl logging for PluginManager and WatchHandle
- Update systemd service with rate limiting and journal output
- Add logrotate config and example config.toml with logging section

musicfs/crates/musicfs-cas/src/reader.rs

@@ -6,6 +6,7 @@ use musicfs_core::FileId;
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 use std::sync::{Arc, RwLock};
+use tracing::{debug, trace};
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ChunkManifest {
@@ -67,10 +68,12 @@ impl FileReader {
         {
             let manifests = self.manifests.read().unwrap();
             if let Some(m) = manifests.get(&file_id) {
+                trace!(file_id = ?file_id, "manifest cache hit");
                 return Ok(m.clone());
             }
         }
 
+        trace!(file_id = ?file_id, "manifest cache miss");
         let Some(fetcher) = &self.fetcher else {
             return Err(ReaderError::ManifestNotFound(file_id));
         };
@@ -103,6 +106,7 @@ impl FileReader {
 
         let end = std::cmp::min(offset + size as u64, manifest.total_size);
         let mut result = BytesMut::with_capacity((end - offset) as usize);
+        let mut chunks_read = 0u32;
 
         for chunk_ref in &manifest.chunks {
             let chunk_start = chunk_ref.offset;
@@ -127,8 +131,11 @@ impl FileReader {
             };
 
             result.extend_from_slice(&chunk_data[read_start..read_end]);
+            chunks_read += 1;
         }
 
+        let bytes_read = result.len() as u64;
+        debug!(file_id = ?file_id, offset, size, chunks_read, bytes_read, "read completed");
         Ok(result.freeze())
     }
 }

musicfs/crates/musicfs-cas/src/store.rs

@@ -4,7 +4,7 @@ use musicfs_core::ChunkHash;
 use std::path::{Path, PathBuf};
 use std::sync::atomic::{AtomicU64, Ordering};
 use tokio::fs;
-use tracing::{debug, warn};
+use tracing::{debug, trace, warn};
 
 const DEFAULT_MAX_SIZE_10GB: u64 = 10 * 1024 * 1024 * 1024;
 const DEFAULT_SHARD_LEVELS_256_SUBDIRS: u8 = 2;
@@ -72,7 +72,7 @@ impl CasStore {
         let path = self.chunk_path(&hash);
 
         if path.exists() {
-            debug!("Chunk {} already exists (dedup)", hash);
+            trace!(hash = %hash, size_bytes = data.len(), "dedup hit");
             return Ok(hash);
         }
 
@@ -94,7 +94,7 @@ impl CasStore {
         self.current_size
             .fetch_add(data.len() as u64, Ordering::SeqCst);
 
-        debug!("Stored chunk {} ({} bytes)", hash, data.len());
+        debug!(hash = %hash, size_bytes = data.len(), "chunk stored");
         Ok(hash)
     }
 
@@ -111,6 +111,7 @@ impl CasStore {
             self.verify_integrity(hash, &data)?;
         }
 
+        debug!(hash = %hash, size_bytes = data.len(), "chunk retrieved");
         Ok(Bytes::from(data))
     }
 
@@ -156,7 +157,7 @@ impl CasStore {
             fs::remove_file(&path).await?;
             self.index.remove(hash.0.as_slice())?;
             self.current_size.fetch_sub(meta.len(), Ordering::SeqCst);
-            debug!("Deleted chunk {}", hash);
+            debug!(hash = %hash, size_bytes = meta.len(), "chunk deleted");
         }
 
         Ok(())