cli: only show Ctrl+C to detach when in a terminal (#178276)

Fixes #178091

cli/src/tunnels/protocol.rs

@@ -166,6 +166,7 @@ pub mod singleton {
 	pub const METHOD_SHUTDOWN: &str = "shutdown";
 	pub const METHOD_STATUS: &str = "status";
 	pub const METHOD_LOG: &str = "log";
+	pub const METHOD_LOG_REPLY_DONE: &str = "log_done";
 
 	#[derive(Serialize)]
 	pub struct LogMessage<'a> {

cli/src/tunnels/singleton_client.rs

@@ -11,10 +11,12 @@ use std::{
 	thread,
 };
 
+use const_format::concatcp;
 use tokio::sync::mpsc;
 
 use crate::{
 	async_pipe::{socket_stream_split, AsyncPipe},
+	constants::IS_INTERACTIVE_CLI,
 	json_rpc::{new_json_rpc, start_json_rpc},
 	log,
 	tunnels::protocol::EmptyObject,
@@ -34,6 +36,19 @@ struct SingletonServerContext {
 	exit_entirely: Arc<AtomicBool>,
 }
 
+const CONTROL_INSTRUCTIONS_COMMON: &str =
+	"Connected to an existing tunnel process running on this machine. You can press:
+
+- \"x\" + Enter to stop the tunnel and exit
+- \"r\" + Enter to restart the tunnel
+";
+
+const CONTROL_INSTRUCTIONS_INTERACTIVE: &str = concatcp!(
+	CONTROL_INSTRUCTIONS_COMMON,
+	"- Ctrl+C to detach
+"
+);
+
 /// Serves a client singleton. Returns true if the process should exit after
 /// this returns, instead of trying to start a tunnel.
 pub async fn start_singleton_client(args: SingletonClientArgs) -> bool {
@@ -80,6 +95,19 @@ pub async fn start_singleton_client(args: SingletonClientArgs) -> bool {
 		Ok(())
 	});
 
+	rpc.register_sync(
+		protocol::singleton::METHOD_LOG_REPLY_DONE,
+		|_: EmptyObject, c| {
+			c.log.result(if *IS_INTERACTIVE_CLI {
+				CONTROL_INSTRUCTIONS_INTERACTIVE
+			} else {
+				CONTROL_INSTRUCTIONS_COMMON
+			});
+
+			Ok(())
+		},
+	);
+
 	rpc.register_sync(
 		protocol::singleton::METHOD_LOG,
 		|log: protocol::singleton::LogMessageOwned, c| {

cli/src/tunnels/singleton_server.rs

@@ -175,14 +175,6 @@ async fn serve_singleton_rpc<C: Clone + Send + Sync + 'static>(
 	}
 }
 
-const CONTROL_INSTRUCTIONS: &str =
-	"Connected to an existing tunnel process running on this machine. You can press:
-
-- Ctrl+C to detach
-- \"x\" + Enter to stop the tunnel and exit
-- \"r\" + Enter to restart the tunnel
-";
-
 /// Log sink that can broadcast and replay log events. Used for transmitting
 /// logs from the singleton to all clients. This should be created and injected
 /// into other services, like the tunnel, before `start_singleton_server`
@@ -223,12 +215,8 @@ impl BroadcastLogSink {
 
 		let _ = log_replay_tx.send(RpcCaller::serialize_notify(
 			&JsonRpcSerializer {},
-			protocol::singleton::METHOD_LOG,
-			protocol::singleton::LogMessage {
-				level: None,
-				prefix: "",
-				message: CONTROL_INSTRUCTIONS,
-			},
+			protocol::singleton::METHOD_LOG_REPLY_DONE,
+			protocol::EmptyObject {},
 		));
 
 		ConcatReceivable::new(log_replay_rx, self.tx.subscribe())