After switching my Debian hosts from Quagga to FRRouting, I noticed that running vtysh has become quite a bit slower especially when making multiple calls to it from my status/monitoring scripts.
This has also been observed by other users of FRRouting (there's an open issue in their bugtracker: #7799).

The Prometheus frr_exporter works around this by directly sending commands to the UNIX sockets of the FRR daemons (PR).

To use the same approach in my monitoring scripts, I wrote a small utility which acts as a drop-in replacement for vtysh and sends the commands directly to the UNIX sockets of the FRR daemons: vtysock
By skipping the parsing and validation checks done in vtysh, vtysock can achieve a significant speed improvement when executing commands.