feat: record-daemon logs to a file

record-daemon/Cargo.lock

@@ -2418,6 +2418,7 @@ dependencies = [
  "tokio-util",
  "toml",
  "tracing",
+ "tracing-appender",
  "tracing-subscriber",
  "uuid",
  "winapi 0.3.9",
@@ -3074,6 +3075,12 @@ version = "2.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "13c2bddecc57b384dee18652358fb23172facb8a2c51ccc10d74c157bdea3292"
 
+[[package]]
+name = "symlink"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a7973cce6668464ea31f176d85b13c7ab3bba2cb3b77a2ed26abd7801688010a"
+
 [[package]]
 name = "syn"
 version = "2.0.117"
@@ -3255,6 +3262,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "743bd48c283afc0388f9b8827b976905fb217ad9e647fae3a379a9283c4def2c"
 dependencies = [
  "deranged",
+ "itoa",
  "num-conv",
  "powerfmt",
  "serde_core",
@@ -3520,6 +3528,19 @@ dependencies = [
  "tracing-core",
 ]
 
+[[package]]
+name = "tracing-appender"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "050686193eb999b4bb3bc2acfa891a13da00f79734704c4b8b4ef1a10b368a3c"
+dependencies = [
+ "crossbeam-channel",
+ "symlink",
+ "thiserror 2.0.18",
+ "time",
+ "tracing-subscriber",
+]
+
 [[package]]
 name = "tracing-attributes"
 version = "0.1.31"

record-daemon/Cargo.toml

@@ -34,6 +34,7 @@ anyhow = "1"
 # Logging
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+tracing-appender = "0.2"
 
 # UUID for recording IDs
 uuid = { version = "1", features = ["v4", "serde"] }

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);