[otel] init otel for app-server (#5469)

codex-rs/Cargo.lock

@@ -848,6 +848,7 @@ dependencies = [
  "codex-protocol",
  "codex-utils-json-to-toml",
  "core_test_support",
+ "opentelemetry-appender-tracing",
  "os_info",
  "pretty_assertions",
  "serde",

codex-rs/app-server/Cargo.toml

@@ -37,6 +37,7 @@ tokio = { workspace = true, features = [
 ] }
 tracing = { workspace = true, features = ["log"] }
 tracing-subscriber = { workspace = true, features = ["env-filter", "fmt"] }
+opentelemetry-appender-tracing = { workspace = true }
 uuid = { workspace = true, features = ["serde", "v7"] }
 
 [dev-dependencies]

codex-rs/app-server/src/lib.rs

@@ -1,13 +1,16 @@
 #![deny(clippy::print_stdout, clippy::print_stderr)]
 
-use std::io::ErrorKind;
-use std::io::Result as IoResult;
-use std::path::PathBuf;
-
 use codex_common::CliConfigOverrides;
 use codex_core::config::Config;
 use codex_core::config::ConfigOverrides;
+use opentelemetry_appender_tracing::layer::OpenTelemetryTracingBridge;
+use std::io::ErrorKind;
+use std::io::Result as IoResult;
+use std::path::PathBuf;
 
+use crate::message_processor::MessageProcessor;
+use crate::outgoing_message::OutgoingMessage;
+use crate::outgoing_message::OutgoingMessageSender;
 use codex_app_server_protocol::JSONRPCMessage;
 use tokio::io::AsyncBufReadExt;
 use tokio::io::AsyncWriteExt;
@@ -18,10 +21,9 @@ use tracing::debug;
 use tracing::error;
 use tracing::info;
 use tracing_subscriber::EnvFilter;
-
-use crate::message_processor::MessageProcessor;
-use crate::outgoing_message::OutgoingMessage;
-use crate::outgoing_message::OutgoingMessageSender;
+use tracing_subscriber::Layer;
+use tracing_subscriber::layer::SubscriberExt;
+use tracing_subscriber::util::SubscriberInitExt;
 
 mod codex_message_processor;
 mod error_code;
@@ -39,13 +41,6 @@ pub async fn run_main(
     codex_linux_sandbox_exe: Option<PathBuf>,
     cli_config_overrides: CliConfigOverrides,
 ) -> IoResult<()> {
-    // Install a simple subscriber so `tracing` output is visible.  Users can
-    // control the log level with `RUST_LOG`.
-    tracing_subscriber::fmt()
-        .with_writer(std::io::stderr)
-        .with_env_filter(EnvFilter::from_default_env())
-        .init();
-
     // Set up channels.
     let (incoming_tx, mut incoming_rx) = mpsc::channel::<JSONRPCMessage>(CHANNEL_CAPACITY);
     let (outgoing_tx, mut outgoing_rx) = mpsc::unbounded_channel::<OutgoingMessage>();
@@ -87,6 +82,29 @@ pub async fn run_main(
             std::io::Error::new(ErrorKind::InvalidData, format!("error loading config: {e}"))
         })?;
 
+    let otel =
+        codex_core::otel_init::build_provider(&config, env!("CARGO_PKG_VERSION")).map_err(|e| {
+            std::io::Error::new(
+                ErrorKind::InvalidData,
+                format!("error loading otel config: {e}"),
+            )
+        })?;
+
+    // Install a simple subscriber so `tracing` output is visible.  Users can
+    // control the log level with `RUST_LOG`.
+    let stderr_fmt = tracing_subscriber::fmt::layer()
+        .with_writer(std::io::stderr)
+        .with_filter(EnvFilter::from_default_env());
+
+    let _ = tracing_subscriber::registry()
+        .with(stderr_fmt)
+        .with(otel.as_ref().map(|provider| {
+            OpenTelemetryTracingBridge::new(&provider.logger).with_filter(
+                tracing_subscriber::filter::filter_fn(codex_core::otel_init::codex_export_filter),
+            )
+        }))
+        .try_init();
+
     // Task: process incoming messages.
     let processor_handle = tokio::spawn({
         let outgoing_message_sender = OutgoingMessageSender::new(outgoing_tx);