Add stubs for grpc interface

Author: ekzhang

Cargo.lock

@@ -5,18 +5,57 @@ syntax = "proto3";
 package sshx;
 
 service SshxService {
-  // Say hello to the user.
-  rpc Hello(HelloRequest) returns (HelloReply);
+  // Create a new SSH session for a given computer.
+  rpc Open(OpenRequest) returns (OpenResponse);
+
+  // Stream real-time commands and terminal outputs to the session.
+  rpc Channel(stream ClientUpdate) returns (stream ServerUpdate);
+
+  // Gracefully shut down an existing SSH session.
+  rpc Close(CloseRequest) returns (CloseResponse);
+}
+
+// Details of bytes exchanged with the terminal.
+message TerminalData {
+  uint32 id = 1; // ID of the shell.
+  string data = 2;
+}
+
+// Request to open an sshx session.
+message OpenRequest {}
+
+// Details of a newly-created sshx session.
+message OpenResponse {
+  string name = 1; // Name of the session.
+  string url = 2; // Public web URL to view as a client.
+}
+
+// Bidirectional streaming update from the client.
+message ClientUpdate {
+  oneof message {
+    string hello = 1; // First stream message, setting the session name.
+    TerminalData data = 2; // Stream data from the terminal.
+    uint32 new_shell = 3; // Acknowledge that a new shell was created.
+    string error = 15;
+  }
+}
+
+// Bidirectional streaming update from the server.
+message ServerUpdate {
+  oneof message {
+    TerminalData data = 1; // Stream commands to update the terminal.
+    uint32 create_shell = 2; // ID of a new shell.
+    uint32 close_shell = 3; // ID of a shell to close.
+    string error = 15;
+  }
 }
 
-// A request for the Hello rpc.
-message HelloRequest {
-  // Request message contains the name to be greeted.
+// Request to stop a sshx session gracefully.
+message CloseRequest {
   string name = 1;
 }
 
-// A reply for the Hello rpc.
-message HelloReply {
-  // Reply contains the greeting message.
-  string message = 1;
+// Server response to closing a session.
+message CloseResponse {
+  bool exists = 1;
 }

crates/sshx-core/proto/sshx.proto

@@ -4,6 +4,7 @@
 #![warn(missing_docs)]
 
 /// Protocol buffer and gRPC definitions, automatically generated by Tonic.
+#[allow(missing_docs)]
 pub mod proto {
     tonic::include_proto!("sshx");
 

crates/sshx-core/src/lib.rs

@@ -9,9 +9,12 @@ axum = "0.4.5"
 hyper = { version = "0.14.17", features = ["full"] }
 sshx-core = { path = "../sshx-core" }
 tokio = { version = "1.16.1", features = ["full"] }
+tokio-stream = "0.1.8"
 tonic = "0.6.2"
 tonic-reflection = "0.3.0"
 tower = { version = "0.4.11", features = ["steer"] }
 tower-http = { version = "0.2.2", features = ["trace"] }
 tracing = "0.1.30"
 tracing-subscriber = "0.3.8"
+
+[features]

crates/sshx-server/Cargo.toml

@@ -1,18 +1,45 @@
 //! Defines gRPC routes and application request logic.
 
-use sshx_core::proto::{sshx_service_server::SshxService, HelloReply, HelloRequest};
-use tonic::{Request, Response, Status};
+use sshx_core::proto::{sshx_service_server::SshxService, *};
+use tokio::sync::mpsc;
+use tokio_stream::{wrappers::ReceiverStream, StreamExt};
+use tonic::{Request, Response, Status, Streaming};
 
 /// Server that handles gRPC requests from the sshx command-line client.
 pub struct GrpcServer;
 
 #[tonic::async_trait]
 impl SshxService for GrpcServer {
-    async fn hello(&self, request: Request<HelloRequest>) -> Result<Response<HelloReply>, Status> {
-        let reply = HelloReply {
-            message: format!("Hello {}!", request.get_ref().name),
-        };
+    type ChannelStream = ReceiverStream<Result<ServerUpdate, Status>>;
 
-        Ok(Response::new(reply))
+    async fn open(&self, request: Request<OpenRequest>) -> Result<Response<OpenResponse>, Status> {
+        let _ = request;
+        Ok(Response::new(OpenResponse {
+            name: "placeholder".into(),
+            url: "https://example.com".into(),
+        }))
+    }
+
+    async fn channel(
+        &self,
+        request: Request<Streaming<ClientUpdate>>,
+    ) -> Result<Response<Self::ChannelStream>, Status> {
+        let mut stream = request.into_inner();
+        let (tx, rx) = mpsc::channel(1);
+
+        tokio::spawn(async move {
+            let _ = stream.next().await;
+            let _ = tx;
+        });
+
+        Ok(Response::new(ReceiverStream::new(rx)))
+    }
+
+    async fn close(
+        &self,
+        request: Request<CloseRequest>,
+    ) -> Result<Response<CloseResponse>, Status> {
+        let _ = request;
+        todo!()
     }
 }

crates/sshx-server/src/grpc.rs

@@ -1,5 +1,5 @@
 use anyhow::Result;
-use sshx_core::proto::HelloRequest;
+use sshx_core::proto::*;
 
 use crate::common::*;
 
@@ -10,11 +10,9 @@ async fn test_rpc() -> Result<()> {
     let server = TestServer::new()?;
     let mut client = server.grpc_client().await?;
 
-    let req = HelloRequest {
-        name: "adam".into(),
-    };
-    let resp = client.hello(req).await?;
-    assert_eq!(&resp.into_inner().message, "Hello adam!");
+    let req = OpenRequest {};
+    let resp = client.open(req).await?;
+    assert!(!resp.into_inner().name.is_empty());
 
     Ok(())
 }