more feature flgs

tonic/Cargo.toml

@@ -18,10 +18,11 @@ tokio-codec = "=0.2.0-alpha.4"
 async-stream = "0.1.1"
 http-body = "0.2.0-alpha.1"
 pin-project = "=0.4.0-alpha.11"
-async-trait = "0.1"
 
-# optional
+# codegen
-# hyper = { version = "=0.13.0-alpha.1", optional = true }
+async-trait = { version = "0.1.13", optional = true }
+
+# transport
 hyper = { git = "https://github.com/hyperium/hyper", features = ["unstable-stream"], optional = true, rev = "2b0405c48c10bca7893c30ea960ac20a41a8578f" }
 tokio = { version = "=0.2.0-alpha.4", default-features = false, features = ["tcp"], optional = true }
 tower = { version = "=0.3.0-alpha.1a", optional = true}
@@ -38,13 +39,11 @@ openssl1 = { package = "openssl", version = "0.10", optional = true }
 tokio-rustls = { version = "0.12.0-alpha.2", optional = true }
 
 [features]
-default = ["transport"]
+default = ["transport", "codegen"]
+codegen = ["async-trait"]
 transport = [
     "hyper",
-    "tower-1",
     "tokio",
-]
-tower-1 = [
     "tower",
     "tower-reconnect",
     "tower-balance",

tonic/src/lib.rs

@@ -20,6 +20,11 @@
 //!
 //! Examples can be found in the [`tonic-examples`] crate.
 //!
+//! # Feature Flags
+//!
+//! - `transport`: Enables the fully featured, batteries included client and server
+//! implementaiton based on [`hyper`], [`tower`] and [`tokio`].
+//!
 //! # Generic implementation
 //!
 //! TODO: write generic implementation docs
@@ -45,7 +50,10 @@ mod request;
 mod response;
 mod status;
 
+/// A re-export of [`async-trait`](https://docs.rs/async-trait) for use with codegen.
+#[cfg(feature = "codegen")]
 pub use async_trait::async_trait;
+
 #[doc(inline)]
 pub use codec::Streaming;
 pub use request::Request;
@@ -55,4 +63,5 @@ pub use status::{Code, Status};
 pub(crate) type Error = Box<dyn std::error::Error + Send + Sync>;
 
 #[doc(hidden)]
+#[cfg(feature = "codegen")]
 pub mod codegen;