First pass at macro

tonic-build/src/lib.rs

@@ -0,0 +1,95 @@
+use prost_build::Config;
+use serde::Serialize;
+use std::{io, path};
+
+pub fn compile_protos<P>(protos: &[P], includes: &[P]) -> io::Result<()>
+where
+    P: AsRef<path::Path>,
+{
+    let mut config = Config::new();
+
+    config.service_generator(Box::new(ServiceGenerator {}));
+
+    config.compile_protos(protos, includes)
+}
+
+pub struct ServiceGenerator {}
+
+impl prost_build::ServiceGenerator for ServiceGenerator {
+    fn generate(&mut self, service: prost_build::Service, _buf: &mut String) {
+        let file = format!(
+            "{}/{}.{}.json",
+            std::env::var("OUT_DIR").unwrap(),
+            service.package,
+            service.name
+        );
+
+        let svc = Service {
+            name: service.name,
+            proto_name: service.proto_name,
+            package: service.package,
+            methods: service
+                .methods
+                .into_iter()
+                .map(|m| Method {
+                    name: m.name,
+                    proto_name: m.proto_name,
+                    input_type: m.input_type,
+                    output_type: m.output_type,
+                    input_proto_type: m.input_proto_type,
+                    output_proto_type: m.output_proto_type,
+                    client_streaming: m.client_streaming,
+                    server_streaming: m.server_streaming,
+                })
+                .collect(),
+        };
+
+        let json = serde_json::to_string(&svc).unwrap();
+
+        std::fs::write(file, json).unwrap();
+    }
+
+    // fn finalize(&mut self, buf: &mut String) {
+    //     let mut fmt = codegen::Formatter::new(buf);
+    //     self.scope
+    //         .fmt(&mut fmt)
+    //         .expect("formatting root scope failed!");
+    //     self.scope = codegen::Scope::new();
+    // }
+}
+
+/// A service descriptor.
+#[derive(Debug, Serialize)]
+pub struct Service {
+    /// The service name in Rust style.
+    pub name: String,
+    /// The service name as it appears in the .proto file.
+    pub proto_name: String,
+    /// The package name as it appears in the .proto file.
+    pub package: String,
+    /// The service methods.
+    pub methods: Vec<Method>,
+}
+
+/// A service method descriptor.
+#[derive(Debug, Serialize)]
+pub struct Method {
+    /// The name of the method in Rust style.
+    pub name: String,
+    /// The name of the method as it appears in the .proto file.
+    pub proto_name: String,
+    /// The input Rust type.
+    pub input_type: String,
+    /// The output Rust type.
+    pub output_type: String,
+    /// The input Protobuf type.
+    pub input_proto_type: String,
+    /// The output Protobuf type.
+    pub output_proto_type: String,
+    // /// The method options.
+    // pub options: prost_types::MethodOptions,
+    /// Identifies if client streams multiple client messages.
+    pub client_streaming: bool,
+    /// Identifies if server streams multiple server messages.
+    pub server_streaming: bool,
+}