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# Codice sorgente per pywws.LogData

    #!/usr/bin/env python

    # pywws - Python software for USB Wireless Weather Stations
    # http://github.com/jim-easterbrook/pywws
    # Copyright (C) 2008-13  Jim Easterbrook  jim@jim-easterbrook.me.uk

    # This program is free software; you can redistribute it and/or
    # modify it under the terms of the GNU General Public License
    # as published by the Free Software Foundation; either version 2
    # of the License, or (at your option) any later version.

    # This program is distributed in the hope that it will be useful,
    # but WITHOUT ANY WARRANTY; without even the implied warranty of
    # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    # GNU General Public License for more details.

    # You should have received a copy of the GNU General Public License
    # along with this program; if not, write to the Free Software
    # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

    """Save weather station history to file
    ::

    %s

    This program / module gets data from the weather station's memory and
    stores it to file. Each time it is run it fetches all data that is
    newer than the last stored data, so it only needs to be run every hour
    or so. As the weather station typically stores two weeks' readings
    (depending on the logging interval), LogData.py could be run quite
    infrequently if you don't need up-to-date data.

    There is no date or time information in the raw weather station data,
    so LogData.py creates a time stamp for each reading. It uses the
    computer's clock, rather than the weather station clock which can not
    be read accurately by the computer. A networked computer should have
    its clock set accurately by `ntp
    <http://en.wikipedia.org/wiki/Network_Time_Protocol>`_.

    Synchronisation with the weather station is achieved by waiting for a
    change in the current data. There are two levels of synchronisation,
    set by the config file or a command line option. Level 0 is quicker,
    but is only accurate to around twelve seconds. Level 1 waits until the
    weather station stores a new logged record, and gets time stamps
    accurate to a couple of seconds. Note that this could take a long
    time, if the logging interval is greater than the recommended five
    minutes.

    """

    __docformat__ = "restructuredtext en"
    __usage__ = """
     usage: python -m pywws.LogData [options] data_dir
     options are:
      -h   | --help     display this help
      -c   | --clear    clear weather station's memory full indicator
      -s n | --sync n   set quality of synchronisation to weather station (0 or 1)
      -v   | --verbose  increase number of informative messages
     data_dir is the root directory of the weather data
    """
    __doc__ %= __usage__
    __usage__ = __doc__.split('\n')[0] + __usage__

    from datetime import datetime, timedelta
    import getopt
    import logging
    import os
    import sys
    import time

    from pywws import DataStore
    from pywws.Logger import ApplicationLogger
    from pywws.Process import HOUR
    from pywws.TimeZone import Local
    from pywws import WeatherStation

    class DataLogger(object):
        def __init__(self, params, status, raw_data):
            self.logger = logging.getLogger('pywws.DataLogger')
            self.params = params
            self.status = status
            self.raw_data = raw_data
            # connect to weather station
            ws_type = self.params.get('fixed', 'ws type')
            if ws_type:
                self.params.unset('fixed', 'ws type')
                self.params.set('config', 'ws type', ws_type)
            ws_type = self.params.get('config', 'ws type', 'Unknown')
            avoid = eval(self.params.get('config', 'usb activity margin', '3.0'))
            self.ws = WeatherStation.weather_station(
                ws_type=ws_type, params=self.params, status=self.status,
                avoid=avoid)
            # check for valid weather station type
            fixed_block = self.check_fixed_block()
            if ws_type not in ('1080', '3080'):
                print "Unknown weather station type. Please edit weather.ini"
                print "and set 'ws type' to '1080' or '3080', as appropriate."
                if fixed_block['lux_wm2_coeff'] == 0.0:
                    print "Your station is probably a '1080' type."
                else:
                    print "Your station is probably a '3080' type."
                sys.exit(1)
            # check computer clock isn't earlier than last stored data
            last_stored = self.raw_data.before(datetime.max)
            if last_stored and datetime.utcnow() < last_stored:
                raise ValueError('Computer time is earlier than last stored data')

        def check_fixed_block(self):
            fixed_block = self.ws.get_fixed_block(unbuffered=True)
            # check clocks
            try:
                s_time = DataStore.safestrptime(
                    fixed_block['date_time'], '%Y-%m-%d %H:%M')
            except Exception:
                s_time = None
            if s_time:
                c_time = datetime.now().replace(second=0, microsecond=0)
                diff = abs(s_time - c_time)
                if diff > timedelta(minutes=2):
                    self.logger.warning(
                        "Computer and weather station clocks disagree by %s (H:M:S).", str(diff))
            # store weather station type
            self.params.set('config', 'ws type', self.ws.ws_type)
            # store info from fixed block
            self.status.unset('fixed', 'pressure offset')
            if not self.params.get('config', 'pressure offset'):
                self.params.set('config', 'pressure offset', '%g' % (
                    fixed_block['rel_pressure'] - fixed_block['abs_pressure']))
            self.params.unset('fixed', 'fixed block')
            self.status.set('fixed', 'fixed block', str(fixed_block))
            return fixed_block

        def catchup(self, last_date, last_ptr):
            fixed_block = self.ws.get_fixed_block(unbuffered=True)
            # get time to go back to
            last_stored = self.raw_data.before(datetime.max)
            if not last_stored:
                last_stored = datetime.min
            last_stored += timedelta(seconds=fixed_block['read_period'] * 30)
            # data_count includes record currently being updated every 48 seconds
            max_count = fixed_block['data_count'] - 1
            count = 0
            while last_date > last_stored and count < max_count:
                data = self.ws.get_data(last_ptr)
                if data['delay'] is None or data['delay'] > 30:
                    self.logger.error('invalid data at %04x, %s',
                                      last_ptr, last_date.isoformat(' '))
                    last_date -= timedelta(minutes=fixed_block['read_period'])
                else:
                    self.raw_data[last_date] = data
                    count += 1
                    last_date -= timedelta(minutes=data['delay'])
                last_ptr = self.ws.dec_ptr(last_ptr)
            if count > 0:
                self.logger.info("%d catchup records", count)

        def log_data(self, sync=None, clear=False):
            fixed_block = self.check_fixed_block()
            # get sync config value
            if sync is None:
                if fixed_block['read_period'] <= 5:
                    sync = int(self.params.get('config', 'logdata sync', '1'))
                else:
                    sync = int(self.params.get('config', 'logdata sync', '0'))
            # get address and date-time of last complete logged data
            self.logger.info('Synchronising to weather station')
            range_hi = datetime.max
            range_lo = datetime.min
            last_delay = self.ws.get_data(self.ws.current_pos())['delay']
            if last_delay == 0:
                prev_date = datetime.min
            else:
                prev_date = datetime.utcnow()
            for data, last_ptr, logged in self.ws.live_data(logged_only=(sync > 1)):
                last_date = data['idx']
                self.logger.debug('Reading time %s', last_date.strftime('%H:%M:%S'))
                if logged:
                    break
                if sync < 2 and self.ws._station_clock:
                    err = last_date - datetime.fromtimestamp(self.ws._station_clock)
                    last_date -= timedelta(
                        minutes=data['delay'], seconds=err.seconds % 60)
                    self.logger.debug('log time %s', last_date.strftime('%H:%M:%S'))
                    last_ptr = self.ws.dec_ptr(last_ptr)
                    break
                if sync < 1:
                    hi = last_date - timedelta(minutes=data['delay'])
                    if last_date - prev_date > timedelta(seconds=50):
                        lo = hi - timedelta(seconds=60)
                    elif data['delay'] == last_delay:
                        lo = hi - timedelta(seconds=60)
                        hi = hi - timedelta(seconds=48)
                    else:
                        lo = hi - timedelta(seconds=48)
                    last_delay = data['delay']
                    prev_date = last_date
                    range_hi = min(range_hi, hi)
                    range_lo = max(range_lo, lo)
                    err = (range_hi - range_lo) / 2
                    last_date = range_lo + err
                    self.logger.debug('est log time %s +- %ds (%s..%s)',
                                      last_date.strftime('%H:%M:%S'), err.seconds,
                                      lo.strftime('%H:%M:%S'), hi.strftime('%H:%M:%S'))
                    if err < timedelta(seconds=15):
                        last_ptr = self.ws.dec_ptr(last_ptr)
                        break
            # go back through stored data, until we catch up with what we've already got
            self.logger.info('Fetching data')
            self.catchup(last_date, last_ptr)
            if clear:
                self.logger.info('Clearing weather station memory')
                ptr = self.ws.fixed_format['data_count'][0]
                self.ws.write_data([(ptr, 1), (ptr+1, 0)])

        def live_data(self, logged_only=False):
            next_hour = datetime.utcnow(
                ).replace(minute=0, second=0, microsecond=0) + HOUR
            next_ptr = None
            for data, ptr, logged in self.ws.live_data(logged_only=logged_only):
                if logged:
                    now = data['idx']
                    if ptr == next_ptr:
                        # data is contiguous with last logged value
                        self.raw_data[now] = data
                        if now >= next_hour:
                            next_hour += HOUR
                            self.check_fixed_block()
                    else:
                        # catch up missing data
                        self.catchup(now, ptr)
                    next_ptr = self.ws.inc_ptr(ptr)
                yield data, logged

    def main(argv=None):
        if argv is None:
            argv = sys.argv
        try:
            opts, args = getopt.getopt(
                argv[1:], "hcs:v", ('help', 'clear', 'sync=', 'verbose'))
        except getopt.error, msg:
            print >>sys.stderr, 'Error: %s\n' % msg
            print >>sys.stderr, __usage__.strip()
            return 1
        # process options
        clear = False
        sync = None
        verbose = 0
        for o, a in opts:
            if o in ('-h', '--help'):
                print __usage__.strip()
                return 0
            elif o in ('-c', '--clear'):
                clear = True
            elif o in ('-s', '--sync'):
                sync = int(a)
            elif o in ('-v', '--verbose'):
                verbose += 1
        # check arguments
        if len(args) != 1:
            print >>sys.stderr, 'Error: 1 argument required\n'
            print >>sys.stderr, __usage__.strip()
            return 2
        logger = ApplicationLogger(verbose)
        root_dir = args[0]
        DataLogger(
            DataStore.params(root_dir), DataStore.status(root_dir),
            DataStore.data_store(root_dir)).log_data(sync=sync, clear=clear)

    if __name__ == "__main__":
        sys.exit(main())

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