cmux/daemon/remote

cmuxd-remote (Go)

Go remote daemon for cmux ssh bootstrap, capability negotiation, and CLI relay.

Commands

1. cmuxd-remote version
2. cmuxd-remote serve --stdio
3. cmuxd-remote cli <command> [args...] — relay cmux commands to the local app over the reverse TCP forward

When invoked as cmux (via wrapper/symlink installed during bootstrap), the binary auto-dispatches to the cli subcommand. This is busybox-style argv[0] detection.

RPC methods (newline-delimited JSON over stdio)

1. hello
2. ping
3. proxy.open
4. proxy.close
5. proxy.write
6. proxy.read
7. session.open
8. session.close
9. session.attach
10. session.resize
11. session.detach
12. session.status

Current integration in cmux:

1. workspace.remote.configure now bootstraps this binary over SSH when missing.
2. Client sends hello before enabling remote proxy transport.
3. Local workspace proxy broker serves SOCKS5 + HTTP CONNECT and tunnels stream traffic through proxy.* RPC over serve --stdio.
4. Daemon status/capabilities are exposed in workspace.remote.status -> remote.daemon (including session.resize.min).

workspace.remote.configure contract notes:

1. port / local_proxy_port accept integer values and numeric strings; explicit null clears each field.
2. Out-of-range values and invalid types return invalid_params.
3. local_proxy_port is an internal deterministic test hook used by bind-conflict regressions.
4. SSH option precedence checks are case-insensitive; user overrides for StrictHostKeyChecking and control-socket keys prevent default injection.

CLI relay

The cli subcommand (or cmux wrapper/symlink) connects to the local cmux app's socket through an SSH reverse TCP forward and relays commands. It supports both v1 text protocol and v2 JSON-RPC commands.

Socket discovery order:

1. --socket <path> flag
2. CMUX_SOCKET_PATH environment variable
3. ~/.cmux/socket_addr file (written by the app after the reverse relay establishes)

For TCP addresses, the CLI retries for up to 15 seconds on connection refused, re-reading ~/.cmux/socket_addr on each attempt to pick up updated relay ports.

Integration additions for the relay path:

1. Bootstrap installs ~/.cmux/bin/cmux wrapper and keeps a default daemon target (~/.cmux/bin/cmuxd-remote-current).
2. A background ssh -N -R process reverse-forwards a TCP port to the local cmux Unix socket. The relay address is written to ~/.cmux/socket_addr on the remote.
3. Relay startup writes ~/.cmux/relay/<port>.daemon_path so the wrapper can route each shell to the correct daemon binary when multiple local cmux instances/versions coexist.