Check whether JACK transport is rolling and toggle state

jack-transport-query.py

import sys
# See https://github.com/SpotlightKid/jack-matchmaker/blob/master/jackmatchmaker/jacklib.py
import jacklib

result = jacklib.jack_status_t()
client = jacklib.client_open("transport-query", jacklib.JackNoStartServer, result)

if result:
    sys.exit("Error connecting to JACK server.")

transport_state = jacklib.transport_query(client, None)

if transport_state == jacklib.JackTransportStopped:
    print("JACK transport stopped, starting it now.")
    jacklib.transport_start(client)
elif transport_state == jacklib.JackTransportRolling:
    print("JACK transport rolling, stopping it now.")
    jacklib.transport_stop(client)
elif transport_state == jacklib.JackTransportStarting:
    print("JACK transport starting, nothing to do.")
else:
    print("Unknown JACK transport state.")

jacklib.client_close(client)

See https://github.com/jackaudio/pyjacklib/blob/master/examples/jack-transport-query.py

Now maintained there in the future.