z_advanced_sub.py

#
# Copyright (c) 2022 ZettaScale Technology
#
# This program and the accompanying materials are made available under the
# terms of the Eclipse Public License 2.0 which is available at
# http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
# which is available at https://www.apache.org/licenses/LICENSE-2.0.
#
# SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
#
# Contributors:
#   ZettaScale Zenoh Team, <zenoh@zettascale.tech>
#
import time

import zenoh
from zenoh.ext import HistoryConfig, Miss, RecoveryConfig, declare_advanced_subscriber


def main(conf: zenoh.Config, key: str):
    # initiate logging
    zenoh.init_log_from_env_or("error")

    print("Opening session...")
    with zenoh.open(conf) as session:
        print(f"Declaring Subscriber on '{key}'...")

        def listener(sample: zenoh.Sample):
            print(
                f">> [Subscriber] Received {sample.kind} ('{sample.key_expr}': '{sample.payload.to_string()}')"
            )

        advanced_sub = declare_advanced_subscriber(
            session,
            key,
            listener,
            history=HistoryConfig(detect_late_publishers=True),
            recovery=RecoveryConfig(heartbeat=True),
            subscriber_detection=True,
        )

        def miss_listener(miss: Miss):
            print(f">> [Subscriber] Missed {miss.nb} samples from {miss.source} !!!")

        advanced_sub.sample_miss_listener(miss_listener)

        print("Press CTRL-C to quit...")
        while True:
            time.sleep(1)


# --- Command line argument parsing --- --- --- --- --- ---
if __name__ == "__main__":
    import argparse

    import common

    parser = argparse.ArgumentParser(
        prog="z_advanced_sub", description="zenoh advanced sub example"
    )
    common.add_config_arguments(parser)
    parser.add_argument(
        "--key",
        "-k",
        dest="key",
        default="demo/example/**",
        type=str,
        help="The key expression to subscribe to.",
    )

    args = parser.parse_args()
    conf = common.get_config_from_args(args)

    main(conf, args.key)