feat: change std to stdout && refactor init_subscriber

Signed-off-by: GFX9 <[email protected]>

crates/xline/src/utils/args.rs

@@ -92,7 +92,7 @@ pub struct ServerArgs {
     #[clap(long, value_parser = parse_metrics_push_protocol, default_value_t = default_metrics_push_protocol())]
     metrics_push_protocol: MetricsPushProtocol,
     /// Log file path
-    #[clap(long, default_value = "/std")]
+    #[clap(long, default_value = "/stdout")]
     log_file: PathBuf,
     /// Log rotate strategy, eg: never, hourly, daily
     #[clap(long, value_parser = parse_rotation, default_value_t = default_rotation())]

crates/xline/src/utils/trace.rs

@@ -6,6 +6,20 @@ use tracing_appender::non_blocking::WorkerGuard;
 use tracing_subscriber::{fmt::format, layer::SubscriberExt, util::SubscriberInitExt, Layer};
 use utils::config::{default_rotation, file_appender, LogConfig, TraceConfig};
 
+/// Return a Box trait from the config
+fn generate_writer(name: &str, log_config: &LogConfig) -> Box<dyn std::io::Write + Send> {
+    match *log_config.path() {
+        Some(ref file_path) if file_path.to_string_lossy() == "/stdout" => {
+            if *log_config.rotation() != default_rotation() {
+                warn!("The log is output to the terminal, so the rotation parameter is ignored.");
+            }
+            Box::new(std::io::stdout())
+        }
+        Some(ref file_path) => Box::new(file_appender(*log_config.rotation(), file_path, name)),
+        None => unreachable!("the path of log cannot be empty in config"),
+    }
+}
+
 /// init tracing subscriber
 /// # Errors
 /// Return error if init failed
@@ -43,47 +57,20 @@ pub fn init_subscriber(
             .install_batch(),
         )
     });
-
     let jaeger_fmt_layer = tracing_subscriber::fmt::layer()
         .with_filter(tracing_subscriber::EnvFilter::from_default_env());
-
-    let prev_layers = tracing_subscriber::registry()
+    let writer = generate_writer(name, log_config);
+    let (non_blocking, guard) = tracing_appender::non_blocking(writer);
+    let log_layer = tracing_subscriber::fmt::layer()
+        .event_format(format().compact())
+        .with_writer(non_blocking)
+        .with_ansi(false)
+        .with_filter(*log_config.level());
+    tracing_subscriber::registry()
         .with(jaeger_fmt_layer)
         .with(jaeger_online_layer)
-        .with(jaeger_offline_layer);
-
-    match *log_config.path() {
-        Some(ref file_path) => {
-            if file_path.to_string_lossy() == "/std" {
-                if *log_config.rotation() != default_rotation() {
-                    warn!(
-                        "The log is output to the terminal, so the rotation parameter is ignored."
-                    );
-                }
-                let stdout_layer = tracing_subscriber::fmt::layer()
-                    .event_format(format().compact())
-                    .with_writer(std::io::stderr)
-                    .with_ansi(false)
-                    .with_filter(*log_config.level());
-
-                prev_layers.with(stdout_layer).try_init()?;
-                return Ok(None);
-            }
-            let mut guard = None;
-            let log_file_layer = log_config.path().as_ref().map(|log_path| {
-                let file_appender = file_appender(*log_config.rotation(), log_path, name);
-                // `WorkerGuard` should be assigned in the `main` function or whatever the entrypoint of the program is.
-                let (non_blocking, guard_inner) = tracing_appender::non_blocking(file_appender);
-                guard = Some(guard_inner);
-                tracing_subscriber::fmt::layer()
-                    .event_format(format().compact())
-                    .with_writer(non_blocking)
-                    .with_ansi(false)
-                    .with_filter(*log_config.level())
-            });
-            prev_layers.with(log_file_layer).try_init()?;
-            Ok(guard)
-        }
-        None => unreachable!(),
-    }
+        .with(jaeger_offline_layer)
+        .with(log_layer)
+        .try_init()?;
+    Ok(Some(guard))
 }