feat(build): Add build_transport builder option (#1130)

tonic-build/src/client.rs

@@ -12,13 +12,14 @@ pub fn generate<T: Service>(
     emit_package: bool,
     proto_path: &str,
     compile_well_known_types: bool,
+    build_transport: bool,
     attributes: &Attributes,
 ) -> TokenStream {
     let service_ident = quote::format_ident!("{}Client", service.name());
     let client_mod = quote::format_ident!("{}_client", naive_snake_case(service.name()));
     let methods = generate_methods(service, emit_package, proto_path, compile_well_known_types);
 
-    let connect = generate_connect(&service_ident);
+    let connect = generate_connect(&service_ident, build_transport);
     let service_doc = generate_doc_comments(service.comment());
 
     let package = if emit_package { service.package() } else { "" };
@@ -109,8 +110,8 @@ pub fn generate<T: Service>(
 }
 
 #[cfg(feature = "transport")]
-fn generate_connect(service_ident: &syn::Ident) -> TokenStream {
-    quote! {
+fn generate_connect(service_ident: &syn::Ident, enabled: bool) -> TokenStream {
+    let connect_impl = quote! {
         impl #service_ident<tonic::transport::Channel> {
             /// Attempt to create a new client by connecting to a given endpoint.
             pub async fn connect<D>(dst: D) -> Result<Self, tonic::transport::Error>
@@ -122,11 +123,17 @@ fn generate_connect(service_ident: &syn::Ident) -> TokenStream {
                 Ok(Self::new(conn))
             }
         }
+    };
+
+    if enabled {
+        connect_impl
+    } else {
+        TokenStream::new()
     }
 }
 
 #[cfg(not(feature = "transport"))]
-fn generate_connect(_service_ident: &syn::Ident) -> TokenStream {
+fn generate_connect(_service_ident: &syn::Ident, _enabled: bool) -> TokenStream {
     TokenStream::new()
 }
 

tonic-build/src/lib.rs

@@ -213,6 +213,14 @@ fn generate_attributes<'a>(
 
 // Generate a singular line of a doc comment
 fn generate_doc_comment<S: AsRef<str>>(comment: S) -> TokenStream {
+    let comment = comment.as_ref();
+
+    let comment = if !comment.starts_with(" ") {
+        format!(" {}", comment)
+    } else {
+        comment.to_string()
+    };
+
     let mut doc_stream = TokenStream::new();
 
     doc_stream.append(Ident::new("doc", Span::call_site()));

tonic-build/src/manual.rs

@@ -367,6 +367,7 @@ impl ServiceGenerator {
                 true,  // emit_package,
                 "",    // proto_path, -- not used
                 false, // compile_well_known_types, -- not used
+                self.builder.build_transport,
                 &Attributes::default(),
             );
             self.clients.extend(client);
@@ -409,6 +410,7 @@ impl ServiceGenerator {
 pub struct Builder {
     build_server: bool,
     build_client: bool,
+    build_transport: bool,
 
     out_dir: Option<PathBuf>,
 }
@@ -418,6 +420,7 @@ impl Default for Builder {
         Self {
             build_server: true,
             build_client: true,
+            build_transport: true,
             out_dir: None,
         }
     }
@@ -445,6 +448,15 @@ impl Builder {
         self
     }
 
+    /// Enable or disable generated clients and servers to have built-in tonic
+    /// transport features.
+    ///
+    /// When the `transport` feature is disabled this does nothing.
+    pub fn build_transport(mut self, enable: bool) -> Self {
+        self.build_transport = enable;
+        self
+    }
+
     /// Set the output directory to generate code to.
     ///
     /// Defaults to the `OUT_DIR` environment variable.

tonic-build/src/prost.rs

@@ -15,6 +15,7 @@ pub fn configure() -> Builder {
     Builder {
         build_client: true,
         build_server: true,
+        build_transport: true,
         file_descriptor_set_path: None,
         out_dir: None,
         extern_path: Vec::new(),
@@ -172,6 +173,7 @@ impl prost_build::ServiceGenerator for ServiceGenerator {
                 self.builder.emit_package,
                 &self.builder.proto_path,
                 self.builder.compile_well_known_types,
+                self.builder.build_transport,
                 &self.builder.client_attributes,
             );
             self.clients.extend(client);
@@ -214,6 +216,7 @@ impl prost_build::ServiceGenerator for ServiceGenerator {
 pub struct Builder {
     pub(crate) build_client: bool,
     pub(crate) build_server: bool,
+    pub(crate) build_transport: bool,
     pub(crate) file_descriptor_set_path: Option<PathBuf>,
     pub(crate) extern_path: Vec<(String, String)>,
     pub(crate) field_attributes: Vec<(String, String)>,
@@ -243,6 +246,15 @@ impl Builder {
         self
     }
 
+    /// Enable or disable generated clients and servers to have built-in tonic
+    /// transport features.
+    ///
+    /// When the `transport` feature is disabled this does nothing.
+    pub fn build_transport(mut self, enable: bool) -> Self {
+        self.build_transport = enable;
+        self
+    }
+
     /// Generate a file containing the encoded `prost_types::FileDescriptorSet` for protocol buffers
     /// modules. This is required for implementing gRPC Server Reflection.
     pub fn file_descriptor_set_path(mut self, path: impl AsRef<Path>) -> Self {

tonic-build/src/server.rs

@@ -173,7 +173,7 @@ fn generate_trait<T: Service>(
 ) -> TokenStream {
     let methods = generate_trait_methods(service, proto_path, compile_well_known_types);
     let trait_doc = generate_doc_comment(&format!(
-        "Generated trait containing gRPC methods that should be implemented for use with {}Server.",
+        " Generated trait containing gRPC methods that should be implemented for use with {}Server.",
         service.name()
     ));
 
@@ -219,7 +219,7 @@ fn generate_trait_methods<T: Service>(
             (false, true) => {
                 let stream = quote::format_ident!("{}Stream", method.identifier());
                 let stream_doc = generate_doc_comment(&format!(
-                    "Server streaming response type for the {} method.",
+                    " Server streaming response type for the {} method.",
                     method.identifier()
                 ));
 
@@ -235,7 +235,7 @@ fn generate_trait_methods<T: Service>(
             (true, true) => {
                 let stream = quote::format_ident!("{}Stream", method.identifier());
                 let stream_doc = generate_doc_comment(&format!(
-                    "Server streaming response type for the {} method.",
+                    " Server streaming response type for the {} method.",
                     method.identifier()
                 ));