hyperium · i18nsite · Jul 9, 2025
diff --git a/tonic/Cargo.toml b/tonic/Cargo.toml
@@ -24,7 +24,8 @@ codegen = ["dep:async-trait"]
 gzip = ["dep:flate2"]
 deflate = ["dep:flate2"]
 zstd = ["dep:zstd"]
-default = ["router", "transport", "codegen", "prost"]
+default = ["router", "transport", "codegen", "prost", "user-agent"]
+user-agent = []
 prost = ["dep:prost"]
 _tls-any = ["dep:tokio-rustls", "dep:tokio", "tokio?/rt", "tokio?/macros"] # Internal. Please choose one of `tls-ring` or `tls-aws-lc`
 tls-ring = ["_tls-any", "tokio-rustls/ring"]

diff --git a/tonic/src/transport/channel/endpoint.rs b/tonic/src/transport/channel/endpoint.rs
@@ -1,19 +1,25 @@
+use std::{fmt, future::Future, net::IpAddr, pin::Pin, str, str::FromStr, time::Duration};
+
+use bytes::Bytes;
+use http::uri::Uri;
+#[cfg(feature = "user-agent")]
+use http::HeaderValue;
+use hyper::rt;
+use hyper_util::client::legacy::connect::HttpConnector;
+use tower_service::Service;
+
 #[cfg(feature = "_tls-any")]
 use super::service::TlsConnector;
-use super::service::{self, Executor, SharedExec};
-use super::uds_connector::UdsConnector;
-use super::Channel;
 #[cfg(feature = "_tls-any")]
 use super::ClientTlsConfig;
+use super::{
+    service::{self, Executor, SharedExec},
+    uds_connector::UdsConnector,
+    Channel,
+};
 #[cfg(feature = "_tls-any")]
 use crate::transport::error;
 use crate::transport::Error;
-use bytes::Bytes;
-use http::{uri::Uri, HeaderValue};
-use hyper::rt;
-use hyper_util::client::legacy::connect::HttpConnector;
-use std::{fmt, future::Future, net::IpAddr, pin::Pin, str, str::FromStr, time::Duration};
-use tower_service::Service;
 
 #[derive(Clone, PartialEq, Eq, Hash)]
 pub(crate) enum EndpointType {
@@ -29,6 +35,7 @@ pub struct Endpoint {
     pub(crate) uri: EndpointType,
     fallback_uri: Uri,
     pub(crate) origin: Option<Uri>,
+    #[cfg(feature = "user-agent")]
     pub(crate) user_agent: Option<HeaderValue>,
     pub(crate) timeout: Option<Duration>,
     pub(crate) concurrency_limit: Option<usize>,
@@ -76,6 +83,7 @@ impl Endpoint {
             uri: EndpointType::Uri(uri.clone()),
             fallback_uri: uri,
             origin: None,
+            #[cfg(feature = "user-agent")]
             user_agent: None,
             concurrency_limit: None,
             rate_limit: None,
@@ -105,6 +113,7 @@ impl Endpoint {
             uri: EndpointType::Uds(uds_filepath.to_string()),
             fallback_uri: Uri::from_static("http://tonic"),
             origin: None,
+            #[cfg(feature = "user-agent")]
             user_agent: None,
             concurrency_limit: None,
             rate_limit: None,
@@ -185,6 +194,7 @@ impl Endpoint {
     /// builder.user_agent("Greeter").expect("Greeter should be a valid header value");
     /// // user-agent: "Greeter tonic/x.x.x"
     /// ```
+    #[cfg(feature = "user-agent")]
     pub fn user_agent<T>(self, user_agent: T) -> Result<Self, Error>
     where
         T: TryInto<HeaderValue>,

diff --git a/tonic/src/transport/channel/service/connection.rs b/tonic/src/transport/channel/service/connection.rs
@@ -1,25 +1,28 @@
-use super::{AddOrigin, Reconnect, SharedExec, UserAgent};
-use crate::{
-    body::Body,
-    transport::{channel::BoxFuture, service::GrpcTimeout, Endpoint},
-};
-use http::{Request, Response, Uri};
-use hyper::rt;
-use hyper::{client::conn::http2::Builder, rt::Executor};
-use hyper_util::rt::TokioTimer;
 use std::{
     fmt,
     task::{Context, Poll},
 };
-use tower::load::Load;
+
+use http::{Request, Response, Uri};
+use hyper::{client::conn::http2::Builder, rt, rt::Executor};
+use hyper_util::rt::TokioTimer;
 use tower::{
     layer::Layer,
     limit::{concurrency::ConcurrencyLimitLayer, rate::RateLimitLayer},
+    load::Load,
     util::BoxService,
     ServiceBuilder, ServiceExt,
 };
 use tower_service::Service;
 
+#[cfg(feature = "user-agent")]
+use super::UserAgent;
+use super::{AddOrigin, Reconnect, SharedExec};
+use crate::{
+    body::Body,
+    transport::{channel::BoxFuture, service::GrpcTimeout, Endpoint},
+};
+
 pub(crate) struct Connection {
     inner: BoxService<Request<Body>, Response<Body>, crate::BoxError>,
 }
@@ -55,13 +58,16 @@ impl Connection {
             settings.max_header_list_size(val);
         }
 
-        let stack = ServiceBuilder::new()
-            .layer_fn(|s| {
-                let origin = endpoint.origin.as_ref().unwrap_or(endpoint.uri()).clone();
+        let stack = ServiceBuilder::new().layer_fn(|s| {
+            let origin = endpoint.origin.as_ref().unwrap_or(endpoint.uri()).clone();
+
+            AddOrigin::new(s, origin)
+        });
+
+        #[cfg(feature = "user-agent")]
+        let stack = stack.layer_fn(|s| UserAgent::new(s, endpoint.user_agent.clone()));
 
-                AddOrigin::new(s, origin)
-            })
-            .layer_fn(|s| UserAgent::new(s, endpoint.user_agent.clone()))
+        let stack = stack
             .layer_fn(|s| GrpcTimeout::new(s, endpoint.timeout))
             .option_layer(endpoint.concurrency_limit.map(ConcurrencyLimitLayer::new))
             .option_layer(endpoint.rate_limit.map(|(l, d)| RateLimitLayer::new(l, d)))

diff --git a/tonic/src/transport/channel/service/mod.rs b/tonic/src/transport/channel/service/mod.rs
@@ -1,7 +1,9 @@
 mod add_origin;
 use self::add_origin::AddOrigin;
 
+#[cfg(feature = "user-agent")]
 mod user_agent;
+#[cfg(feature = "user-agent")]
 use self::user_agent::UserAgent;
 
 mod reconnect;

diff --git a/tonic/src/transport/error.rs b/tonic/src/transport/error.rs
@@ -17,7 +17,7 @@ pub(crate) enum Kind {
     Transport,
     #[cfg(feature = "channel")]
     InvalidUri,
-    #[cfg(feature = "channel")]
+    #[cfg(all(feature = "channel", feature = "user-agent"))]
     InvalidUserAgent,
     #[cfg(all(feature = "_tls-any", feature = "channel"))]
     InvalidTlsConfigForUds,
@@ -44,7 +44,7 @@ impl Error {
         Error::new(Kind::InvalidUri)
     }
 
-    #[cfg(feature = "channel")]
+    #[cfg(all(feature = "channel", feature = "user-agent"))]
     pub(crate) fn new_invalid_user_agent() -> Self {
         Error::new(Kind::InvalidUserAgent)
     }
@@ -54,7 +54,7 @@ impl Error {
             Kind::Transport => "transport error",
             #[cfg(feature = "channel")]
             Kind::InvalidUri => "invalid URI",
-            #[cfg(feature = "channel")]
+            #[cfg(all(feature = "channel", feature = "user-agent"))]
             Kind::InvalidUserAgent => "user agent is not a valid header value",
             #[cfg(all(feature = "_tls-any", feature = "channel"))]
             Kind::InvalidTlsConfigForUds => "cannot apply TLS config for unix domain socket",