feat: manage multiple ssh machines from one client (#3670)

1 files changed, 31 insertions, 15 deletions

diff --git a/src/server/autodetect.rs b/src/server/autodetect.rs
index bd364a70..e6fdaaa4 100644
--- a/src/server/autodetect.rs
+++ b/src/server/autodetect.rs
@@ -142,7 +142,7 @@ fn client_protocol_accepts_hello(socket_path: &Path) -> io::Result<bool> {
     }
 }
 
-fn validate_running_server_compatibility() -> io::Result<()> {
+fn validate_running_server_compatibility(saved_federation: bool) -> io::Result<()> {
     let Some(status) = read_server_status()? else {
         return Err(io::Error::other(format!(
             "a herdr server is listening, but its status API is unavailable.\n\n{}\nIf that fails, stop the old server process manually.",
@@ -150,16 +150,23 @@ fn validate_running_server_compatibility() -> io::Result<()> {
         )));
     };
 
-    let endpoint_generation = status
-        .capabilities
-        .as_ref()
-        .and_then(|capabilities| capabilities.endpoint_protocol_generation);
-    if endpoint_generation == Some(crate::protocol::endpoint::ENDPOINT_PROTOCOL_GENERATION) {
+    let capabilities = status.capabilities.as_ref();
+    let endpoint_generation =
+        capabilities.and_then(|capabilities| capabilities.endpoint_protocol_generation);
+    let surface_interest = capabilities.is_some_and(|capabilities| capabilities.surface_interest);
+    if endpoint_generation == Some(crate::protocol::endpoint::ENDPOINT_PROTOCOL_GENERATION)
+        && (!saved_federation || surface_interest)
+    {
         return Ok(());
     }
 
+    let requirement = if saved_federation && !surface_interest {
+        "saved SSH machines require surface lifecycle support"
+    } else {
+        "the stable endpoint generation is incompatible"
+    };
     Err(io::Error::other(format!(
-        "This session predates Herdr's stable endpoint protocol and needs one final server update.\n\nserver: v{} endpoint generation {}\nclient: v{} endpoint generation {}\n\n{}",
+        "This session needs one final server update before Herdr can attach ({requirement}).\n\nserver: v{} endpoint generation {}\nclient: v{} endpoint generation {}\n\n{}",
         status.version.as_deref().unwrap_or("unknown"),
         endpoint_generation
             .map(|value| value.to_string())
@@ -285,18 +292,27 @@ pub fn wait_for_server_socket(socket_path: &Path, timeout: Duration) -> io::Resu
 /// 1. Check if a server is listening on the client socket
 /// 2. If no server → spawn server daemon → wait for socket readiness
 /// 3. Run the thin client (which connects to the server)
-pub fn auto_detect_launch() -> io::Result<()> {
+pub fn auto_detect_launch(saved_federation: bool) -> io::Result<()> {
     let socket_path = client_socket_path();
     info!(path = %socket_path.display(), "auto-detect launch starting");
 
-    if is_server_listening_at(&socket_path) {
-        validate_running_server_compatibility()?;
+    let startup = if is_server_listening_at(&socket_path) {
         info!("server already running, attaching as client");
+        if saved_federation {
+            Ok(())
+        } else {
+            validate_running_server_compatibility(false)
+        }
     } else {
         info!("no server running, spawning server daemon");
-        spawn_server_daemon()?;
-        wait_for_server_socket(&socket_path, SERVER_READY_TIMEOUT)?;
-        info!("server ready, attaching as client");
+        spawn_server_daemon()
+            .and_then(|_| wait_for_server_socket(&socket_path, SERVER_READY_TIMEOUT))
+    };
+    if let Err(error) = startup {
+        if !saved_federation {
+            return Err(error);
+        }
+        tracing::warn!(%error, "Local startup failed; keeping saved machines available");
     }
 
     // Now attach as a thin client.
@@ -522,7 +538,7 @@ test "$sid" = "$$"
         let path = dir.join("api.sock");
         std::env::set_var(crate::api::SOCKET_PATH_ENV_VAR, &path);
 
-        let err = validate_running_server_compatibility().unwrap_err();
+        let err = validate_running_server_compatibility(false).unwrap_err();
 
         assert!(
             err.to_string().contains("status API is unavailable"),
@@ -558,7 +574,7 @@ test "$sid" = "$$"
             stream.flush().unwrap();
         });
 
-        let err = validate_running_server_compatibility().unwrap_err();
+        let err = validate_running_server_compatibility(false).unwrap_err();
         let message = err.to_string();
 
         let _ = handle.join();