feat: record-daemon logs to a file

record-daemon/src/main.rs

@@ -42,6 +42,10 @@ struct Args {
     /// Socket path for IPC.
     #[arg(short, long)]
     socket: Option<std::path::PathBuf>,
+
+    /// Path to log file. If not specified, logs to stdout/stderr.
+    #[arg(short, long, value_name = "PATH")]
+    log_file: Option<std::path::PathBuf>,
 }
 
 /// Main daemon structure.
@@ -579,15 +583,49 @@ impl Daemon {
     }
 }
 
-/// Initialize logging.
-fn init_logging(level: &str) {
+/// Initialize logging with optional file output.
+fn init_logging(level: &str, log_file: Option<&std::path::Path>) {
     let filter = tracing_subscriber::EnvFilter::try_from_default_env()
         .unwrap_or_else(|_| tracing_subscriber::EnvFilter::new(level));
 
-    tracing_subscriber::registry()
-        .with(filter)
-        .with(tracing_subscriber::fmt::layer())
-        .init();
+    if let Some(log_path) = log_file {
+        // Ensure parent directory exists
+        if let Some(parent) = log_path.parent() {
+            let _ = std::fs::create_dir_all(parent);
+        }
+
+        // Use file appender for logging
+        let prefix = log_path
+            .file_stem()
+            .and_then(|s| s.to_str())
+            .unwrap_or("daemon");
+        
+        let file_appender = tracing_appender::rolling::RollingFileAppender::builder()
+            .rotation(tracing_appender::rolling::Rotation::DAILY)
+            .filename_prefix(prefix)
+            .filename_suffix("log")
+            .build(log_path.parent().unwrap_or(std::path::Path::new(".")))
+            .expect("Failed to create log file appender");
+
+        let (non_blocking, _guard) = tracing_appender::non_blocking(file_appender);
+        
+        // Store the guard to prevent it from being dropped
+        // We leak it intentionally to keep logging working for the daemon's lifetime
+        std::mem::forget(_guard);
+
+        tracing_subscriber::registry()
+            .with(filter)
+            .with(tracing_subscriber::fmt::layer().with_writer(non_blocking))
+            .init();
+
+        eprintln!("Logging to file: {}", log_path.display());
+    } else {
+        // Log to stdout/stderr
+        tracing_subscriber::registry()
+            .with(filter)
+            .with(tracing_subscriber::fmt::layer())
+            .init();
+    }
 
     // Set up panic hook to log panics
     std::panic::set_hook(Box::new(|panic_info| {
@@ -614,7 +652,7 @@ async fn main() -> Result<()> {
     let args = Args::parse();
 
     // Initialize logging
-    init_logging(&args.log_level);
+    init_logging(&args.log_level, args.log_file.as_deref());
 
     info!("Record Daemon v{} starting", record_daemon::VERSION);