[Rust Frontend] Extract shared tracing setup logic into vllm-tracing (#50129)

Signed-off-by: Bugen Zhao <i@bugenzhao.com>

rust/src/bench/Cargo.toml

@@ -32,9 +32,9 @@ tokenizers.workspace = true
 tokio.workspace = true
 tokio-stream.workspace = true
 tracing.workspace = true
-tracing-subscriber.workspace = true
 url.workspace = true
 uuid.workspace = true
+vllm-tracing.workspace = true
 
 [lints]
 workspace = true

rust/src/bench/src/main.rs

@@ -19,18 +19,8 @@ struct Cli {
     args: vllm_bench::BenchServeArgs,
 }
 
-// TODO: unify the tracing subscriber used by different binaries.
-fn init_tracing() {
-    let filter = tracing_subscriber::EnvFilter::try_from_default_env()
-        .unwrap_or_else(|_| tracing_subscriber::EnvFilter::new("info"));
-    let _ = tracing_subscriber::fmt()
-        .with_env_filter(filter)
-        .with_writer(std::io::stderr)
-        .try_init();
-}
-
 fn main() -> anyhow::Result<()> {
-    init_tracing();
+    vllm_tracing::init_tracing("Bench");
 
     let cli = Cli::parse();
     vllm_bench::prepare_process();

rust/src/cmd/Cargo.toml

@@ -23,17 +23,16 @@ serde.workspace = true
 serde_json.workspace = true
 serde_with.workspace = true
 thiserror-ext.workspace = true
-time.workspace = true
 tokio = { workspace = true, features = ["signal"] }
 tokio-util.workspace = true
 tracing.workspace = true
-tracing-subscriber.workspace = true
 uuid.workspace = true
 vllm-bench.workspace = true
 vllm-chat.workspace = true
 vllm-engine-core-client.workspace = true
 vllm-managed-engine.workspace = true
 vllm-server.workspace = true
+vllm-tracing.workspace = true
 
 [dev-dependencies]
 expect-test.workspace = true

rust/src/cmd/src/main.rs

@@ -2,7 +2,6 @@
 // SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 mod cli;
-mod logging;
 
 use std::env;
 use std::ffi::OsStr;
@@ -89,7 +88,7 @@ fn main() -> Result<()> {
             "serve" | "frontend" => "RustFrontend",
             _ => "Rust",
         };
-    logging::init_tracing(process_label);
+    vllm_tracing::init_tracing(process_label);
 
     let cli = Cli::parse();
 

rust/src/tracing/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "vllm-tracing"
+version.workspace = true
+edition.workspace = true
+description = "Shared tracing subscriber and log formatting for vLLM Rust binaries"
+license.workspace = true
+
+[dependencies]
+time.workspace = true
+tracing.workspace = true
+tracing-subscriber.workspace = true
+
+[lints]
+workspace = true

rust/src/tracing/src/lib.rs

@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
+//! Shared tracing subscriber and log formatting for vLLM Rust binaries.
+
 use std::{env, fmt, process};
 
 use time::UtcOffset;
@@ -26,8 +28,8 @@ const RESET: &str = "\x1b[0m";
 const VLLM_TIME_FORMAT: &[time::format_description::FormatItem<'static>] =
     format_description!("[month]-[day] [hour]:[minute]:[second]");
 
-/// Install the process-wide vLLM-style tracing subscriber for the CLI binary.
-pub(crate) fn init_tracing(process_label: &str) {
+/// Install the process-wide vLLM-style tracing subscriber.
+pub fn init_tracing(process_label: &str) {
     let filter = build_targets_filter(
         env::var("VLLM_LOGGING_LEVEL").ok().as_deref(),
         env::var("RUST_LOG").ok().as_deref(),