ci: probe socket connectivity before sending inference RPC

The runtime smoke test leaves stale socket files after stopping
baudbot. When the inference smoke starts baudbot fresh, the alias
symlink still points to the old dead socket. Fix by verifying the
socket is connectable (not just that the file exists) before
proceeding with the RPC.

Author: benvinegar

bin/ci/smoke-agent-inference.sh

@@ -36,6 +36,20 @@ cleanup() {
 }
 trap cleanup EXIT
 
+socket_is_connectable() {
+  local sock="$1"
+  sudo -u "$AGENT_USER" python3 -c "
+import socket, sys
+s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+try:
+    s.settimeout(2)
+    s.connect(sys.argv[1])
+    s.close()
+except Exception:
+    sys.exit(1)
+" "$sock" 2>/dev/null
+}
+
 wait_for_control_socket() {
   local deadline=$((SECONDS + START_TIMEOUT_SECONDS))
   local target=""
@@ -47,7 +61,7 @@ wait_for_control_socket() {
         if [[ "$target" != /* ]]; then
           target="${CONTROL_DIR}/${target}"
         fi
-        if [[ -S "$target" ]]; then
+        if [[ -S "$target" ]] && socket_is_connectable "$target"; then
           printf '%s\n' "$target"
           return 0
         fi