Use BatchSpanProcessor for console writer

Author: friendlymatthew

src/config.rs

@@ -400,4 +400,18 @@ mod tests {
             super::ConsoleOptions::default().with_min_log_level(tracing::Level::DEBUG);
         assert_eq!(console_options.min_log_level, tracing::Level::DEBUG);
     }
+
+    #[tokio::test]
+    async fn test_console_with_tokio_sleep() {
+        // token is invalid, so exports will fail, but it was a necessary part of reproducing the issue
+        let shutdown_handler = crate::configure()
+            .with_token("abc123")
+            .install_panic_handler()
+            .finish()
+            .unwrap();
+
+        tokio::time::sleep(tokio::time::Duration::from_secs(1)).await;
+
+        shutdown_handler.shutdown().ok();
+    }
 }

src/lib.rs

@@ -106,13 +106,11 @@ use bridges::tracing::LogfireTracingPendingSpanNotSentLayer;
 use config::get_base_url_from_token;
 use opentelemetry::trace::TracerProvider;
 use opentelemetry_sdk::metrics::{PeriodicReader, SdkMeterProvider};
-use opentelemetry_sdk::trace::{
-    BatchConfigBuilder, BatchSpanProcessor, SimpleSpanProcessor, SpanProcessor,
-};
+use opentelemetry_sdk::trace::{BatchConfigBuilder, BatchSpanProcessor, SpanProcessor};
 use opentelemetry_sdk::trace::{SdkTracerProvider, Tracer};
 use thiserror::Error;
-use tracing::Subscriber;
 use tracing::level_filters::LevelFilter;
+use tracing::Subscriber;
 use tracing_subscriber::layer::SubscriberExt;
 
 use crate::bridges::tracing::LogfireTracingLayer;
@@ -531,12 +529,12 @@ impl LogfireConfigBuilder {
                     logfire_base_url,
                     http_headers.clone(),
                 )?)
-                .with_batch_config(
-                    BatchConfigBuilder::default()
-                        .with_scheduled_delay(Duration::from_millis(500)) // 500 matches Python
-                        .build(),
-                )
-                .build(),
+                    .with_batch_config(
+                        BatchConfigBuilder::default()
+                            .with_scheduled_delay(Duration::from_millis(500)) // 500 matches Python
+                            .build(),
+                    )
+                    .build(),
             );
         }
 
@@ -551,9 +549,15 @@ impl LogfireConfigBuilder {
             .map(Arc::new);
 
         if let Some(console_writer) = console_writer.clone() {
-            tracer_provider_builder = tracer_provider_builder.with_span_processor(
-                SimpleSpanProcessor::new(SimpleConsoleSpanExporter::new(console_writer)),
-            );
+            // Use BatchSpanProcessor instead of SimpleSpanProcessor to avoid deadlocks.
+            // BatchSpanProcessor uses a dedicated background thread, making it safer in async environments.
+            tracer_provider_builder =
+                tracer_provider_builder.with_span_processor(BatchSpanProcessor::new(
+                    SimpleConsoleSpanExporter::new(console_writer),
+                    BatchConfigBuilder::default()
+                        .with_scheduled_delay(Duration::ZERO)
+                        .build(),
+                ));
         }
 
         for span_processor in self.additional_span_processors {
@@ -593,7 +597,7 @@ impl LogfireConfigBuilder {
                     logfire_base_url,
                     http_headers,
                 )?)
-                .build();
+                    .build();
 
                 meter_provider_builder = meter_provider_builder.with_reader(metric_reader);
             }
@@ -816,7 +820,7 @@ mod test_utils;
 
 #[cfg(test)]
 mod tests {
-    use crate::{ConfigureError, config::SendToLogfire};
+    use crate::{config::SendToLogfire, ConfigureError};
 
     #[test]
     fn test_send_to_logfire() {