stream access logs and improve access log format (#581)

crates/brightstaff/src/handlers/chat_completions.rs

@@ -153,7 +153,7 @@ pub async fn chat(
         Ok(route) => match route {
             Some((_, model_name)) => model_name,
             None => {
-               debug!(
+               info!(
                     "No route determined, using default model from request: {}",
                     chat_completions_request_for_arch_router.model
                 );

crates/brightstaff/src/utils/tracing.rs

@@ -1,9 +1,46 @@
 use std::sync::OnceLock;
+use std::fmt;
 
 use opentelemetry::global;
 use opentelemetry_sdk::{propagation::TraceContextPropagator, trace::SdkTracerProvider};
 use opentelemetry_stdout::SpanExporter;
 use tracing_subscriber::EnvFilter;
+use tracing_subscriber::fmt::{format, time::FormatTime, FmtContext, FormatEvent, FormatFields};
+use tracing::{Event, Subscriber};
+use time::macros::format_description;
+
+struct BracketedTime;
+
+impl FormatTime for BracketedTime {
+    fn format_time(&self, w: &mut format::Writer<'_>) -> fmt::Result {
+        let now = time::OffsetDateTime::now_utc();
+        write!(w, "[{}]", now.format(&format_description!("[year]-[month]-[day] [hour]:[minute]:[second].[subsecond digits:3]")).unwrap())
+    }
+}
+
+struct BracketedFormatter;
+
+impl<S, N> FormatEvent<S, N> for BracketedFormatter
+where
+    S: Subscriber + for<'a> tracing_subscriber::registry::LookupSpan<'a>,
+    N: for<'a> FormatFields<'a> + 'static,
+{
+    fn format_event(
+        &self,
+        ctx: &FmtContext<'_, S, N>,
+        mut writer: format::Writer<'_>,
+        event: &Event<'_>,
+    ) -> fmt::Result {
+        let timer = BracketedTime;
+        timer.format_time(&mut writer)?;
+
+        write!(writer, "[{}] ", event.metadata().level().to_string().to_lowercase())?;
+
+        ctx.field_format().format_fields(writer.by_ref(), event)?;
+
+        writeln!(writer)
+    }
+}
 
 static INIT_LOGGER: OnceLock<SdkTracerProvider> = OnceLock::new();
 
@@ -22,6 +59,7 @@ pub fn init_tracer() -> &'static SdkTracerProvider {
             .with_env_filter(
                 EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new("info")),
             )
+            .event_format(BracketedFormatter)
             .init();
 
         provider