ntp_monitor.py

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#!/usr/bin/env python
# -*- coding: utf-8 -*-
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import roslib
roslib.load_manifest('diagnostic_common_diagnostics')
import rospy
import diagnostic_updater as DIAG

import sys
import socket
from subprocess import Popen, PIPE
import time
import re


def ntp_diag(st, host, off, error_offset):
    try:
        p = Popen(["ntpdate", "-q", host], stdout=PIPE, stdin=PIPE, stderr=PIPE)
        res = p.wait()
        (o,e) = p.communicate()
    except OSError, (errno, msg):
        if errno == 4:
            return None #ctrl-c interrupt
        else:
            raise
    if (res == 0):
        measured_offset = float(re.search("offset (.*),", o).group(1))*1000000

        st.level = DiagnosticStatus.OK
        st.message = "OK"
        st.values = [ KeyValue("Offset (us)", str(measured_offset)),
                        KeyValue("Offset tolerance (us)", str(off)),
                        KeyValue("Offset tolerance (us) for Error", str(error_offset)) ]

        if (abs(measured_offset) > off):
            st.level = DiagnosticStatus.WARN
            st.message = "NTP Offset Too High"
        if (abs(measured_offset) > error_offset):
            st.level = DiagnosticStatus.ERROR
            st.message = "NTP Offset Too High"

    else:
        st.level = DiagnosticStatus.ERROR
        st.message = "Error Running ntpdate. Returned %d" % res
        st.values = [ KeyValue("Offset (us)", "N/A"),
                        KeyValue("Offset tolerance (us)", str(off)),
                        KeyValue("Offset tolerance (us) for Error", str(error_offset)),
                        KeyValue("Output", o),
                        KeyValue("Errors", e) ]

    return st


def ntp_monitor(ntp_hostname, offset=500, self_offset=500, diag_hostname = None, error_offset = 5000000, do_self_test=True):
    pub = rospy.Publisher("/diagnostics", DiagnosticArray)
    rospy.init_node(ntp_monitor, anonymous=True)

    hostname = socket.gethostname()
    if diag_hostname is None:
        diag_hostname = hostname

    stat = DiagnosticStatus()
    stat.level = DiagnosticStatus.OK
    stat.name = "NTP offset from "+ diag_hostname + " to " + ntp_hostname
    stat.message = "OK"
    stat.hardware_id = hostname
    stat.values = []

    self_stat = DiagnosticStatus()
    self_stat.level = DiagnosticStatus.OK
    self_stat.name = "NTP self-offset for "+ diag_hostname
    self_stat.message = "OK"
    self_stat.hardware_id = hostname
    self_stat.values = []

    while not rospy.is_shutdown():
        msg = DiagnosticArray()
        msg.header.stamp = rospy.get_rostime()

        st = ntp_diag(stat, ntp_hostname, offset, error_offset)
        if st is not None:
            msg.status.append(st)

        if do_self_test:
            st = ntp_diag(self_stat, hostname, self_offset, error_offset)
            if st is not None:
                msg.status.append(st)

        pub.publish(msg)
        time.sleep(1)

def ntp_monitor_main(argv=sys.argv):
    import optparse
    parser = optparse.OptionParser(usage="usage: ntp_monitor ntp-hostname []")
    parser.add_option("--offset-tolerance", dest="offset_tol",
                      action="store", default=500,
                      help="Offset from NTP host", metavar="OFFSET-TOL")
    parser.add_option("--error-offset-tolerance", dest="error_offset_tol",
                      action="store", default=5000000,
                      help="Offset from NTP host. Above this is error", metavar="OFFSET-TOL")
    parser.add_option("--self_offset-tolerance", dest="self_offset_tol",
                      action="store", default=500,
                      help="Offset from self", metavar="SELF_OFFSET-TOL")
    parser.add_option("--diag-hostname", dest="diag_hostname",
                      help="Computer name in diagnostics output (ex: 'c1')",
                      metavar="DIAG_HOSTNAME",
                      action="store", default=None)
    parser.add_option("--no-self-test", dest="do_self_test",
                      help="Disable self test",
                      action="store_false", default=True)
    options, args = parser.parse_args(rospy.myargv())

    if (len(args) != 2):
        parser.error("Invalid arguments. Must have HOSTNAME [args]. %s" % args)


    try:
        offset = int(options.offset_tol)
        self_offset = int(options.self_offset_tol)
        error_offset = int(options.error_offset_tol)
    except:
        parser.error("Offsets must be numbers")

    ntp_monitor(args[1], offset, self_offset, options.diag_hostname, error_offset, options.do_self_test)


if __name__ == "__main__":
    try:
        ntp_monitor_main(rospy.myargv())
    except KeyboardInterrupt: pass
    except SystemExit: pass
    except:
        import traceback
        traceback.print_exc()