Dealing with the socket interface directly is painful and pointless, given there are a few nice command line interfaces.
Example https://pypi.org/project/haproxy-cli/ :
aborrero@toolsbeta-test-k8s-haproxy-5:~$ haproxy-cli -k /run/haproxy/haproxy.sock -b k8s-api -c servers Name: FRONTEND Status: OPEN Weight: bIn: 508877 bOut: 6801416 Name: toolsbeta-test-k8s-control-7.toolsbeta.eqiad1.wikimedia.cloud Status: UP Weight: 100 bIn: 145098 bOut: 1992708 Name: toolsbeta-test-k8s-control-8.toolsbeta.eqiad1.wikimedia.cloud Status: UP Weight: 100 bIn: 141309 bOut: 1919985 Name: toolsbeta-test-k8s-control-9.toolsbeta.eqiad1.wikimedia.cloud Status: UP Weight: 100 bIn: 222470 bOut: 2888723