Implement configurable logging with tracing

- Replace eprintln! with tracing macros for configurable log levels
- Set up tracing_subscriber with level filtering from config
- Log format: YYYY-MM-DDTHH:MM:SSZ LEVEL IP "request" STATUS "message"
- Success logs: INFO level for 20 responses
- Error logs: WARN for 41/51, ERROR for 59
- Rate limiting and file serving now properly logged
- Remove unused RequestLogger::log_success method

src/logging.rs

@@ -16,12 +16,20 @@ impl RequestLogger {
         }
     }
 
-    pub fn log_success(self, status_code: u8) {
-        println!("{} \"{}\" {}", self.client_ip, self.request_url, status_code);
-    }
+
 
     pub fn log_error(self, status_code: u8, error_message: &str) {
-        eprintln!("{} \"{}\" {} \"{}\"", self.client_ip, self.request_url, status_code, error_message);
+        let level = match status_code {
+            41 | 51 => tracing::Level::WARN,
+            59 => tracing::Level::ERROR,
+            _ => tracing::Level::ERROR,
+        };
+
+        match level {
+            tracing::Level::WARN => tracing::warn!("{} \"{}\" {} \"{}\"", self.client_ip, self.request_url, status_code, error_message),
+            tracing::Level::ERROR => tracing::error!("{} \"{}\" {} \"{}\"", self.client_ip, self.request_url, status_code, error_message),
+            _ => {}
+        }
     }
 
 
@@ -35,8 +43,28 @@ fn extract_client_ip(stream: &TlsStream<TcpStream>) -> String {
     }
 }
 
-pub fn init_logging(_level: &str) {
-    // Simple logging using stdout/stderr - systemd will capture this
+pub fn init_logging(level: &str) {
+    use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
+
+    let level = match level.to_lowercase().as_str() {
+        "error" => tracing::Level::ERROR,
+        "warn" => tracing::Level::WARN,
+        "info" => tracing::Level::INFO,
+        "debug" => tracing::Level::DEBUG,
+        "trace" => tracing::Level::TRACE,
+        _ => {
+            eprintln!("Warning: Invalid log level '{}', defaulting to 'info'", level);
+            tracing::Level::INFO
+        }
+    };
+
+    tracing_subscriber::registry()
+        .with(tracing_subscriber::fmt::layer()
+            .compact()
+            .with_target(false)
+            .with_thread_ids(false))
+        .with(tracing_subscriber::filter::LevelFilter::from_level(level))
+        .init();
 }
 
 #[cfg(test)]