Node to count the number of messages on topics.

wc.py

#! /usr/bin/env python3
from sys import argv

import rospy


def cb(msg, cb_args):
    counters, i = cb_args
    counters[i] += 1


def print_counts(ev):
    topics = print_counts._topics
    counters = print_counts._counters
    print("{" + ', '.join((f"'{t}': {c}" for t, c in zip(topics, counters))), "}")


def main():
    rospy.init_node("wc", argv, anonymous=True)

    if len(argv) <= 1:
        rospy.logfatal(f"Usage:\n$ {argv[0]} /topic_name_1 _param:=value1 /topic2/name __ns:=a_ns")
    topics = []
    counters = []
    subs = []
    for i, topic in enumerate(argv[1:]):
        topics.append(topic)
        counters.append(0)
        subs.append(rospy.Subscriber(topic, rospy.AnyMsg, queue_size=1000, callback=cb, callback_args=(counters, i)))

    print_counts._topics = topics
    print_counts._counters = counters

    logger = rospy.Timer(rospy.Duration(1, 0), print_counts)
    try:
        rospy.spin()
    except Exception as e:
        print(e)
    finally:
        print(zip(topics, counters))


if __name__ == "__main__":
    main()