CheckDewarWeights

Bases: KPFTranslatorFunction

Check the weight of the red and green dewars and send email if they are lower than expected.

ARGS:

:dewar: str Which dewar to check? red or green :email: bool If True, send email if dewar weight is low

Source code in kpf/utils/CheckDewarWeights.py 
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class CheckDewarWeights(KPFTranslatorFunction):
    '''Check the weight of the red and green dewars and send email if they are
    lower than expected.

    ARGS:
    =====
    :dewar: `str` Which dewar to check? red or green
    :email: `bool` If True, send email if dewar weight is low
    '''
    @classmethod
    def pre_condition(cls, args, logger, cfg):
        pass

    @classmethod
    def perform(cls, args, logger, cfg):
        dewar = args.get('dewar', 'green')

        fill_time = cfg.getint('LN2', 'fill_time', fallback=21)
        low_weight = cfg.getint('LN2', f'low_weight_{dewar}', fallback=90)
        use_rate = cfg.getint('LN2', f'use_rate_{dewar}', fallback=40)

        utcnow = datetime.utcnow()
        if utcnow.hour < fill_time:
            time_until_fill = fill_time - (utcnow.hour + utcnow.minute/60)
        else:
            time_until_fill = fill_time+24 - (utcnow.hour + utcnow.minute/60)

        kpffill = ktl.cache('kpffill')

        weight = kpffill[f'{dewar}WEIGHT'].read(binary=True)
        weight_at_fill = weight - (time_until_fill/24)*use_rate
        if weight_at_fill > low_weight:
            # Dewar fill level is ok
            print('Dewar weight is OK')
        else:
            # Dewar fill level is not ok
            print('Dewar weight is low!')
            if args.get('email', False) is True:
                try:
                    msg = [f'KPF {dewar} dewar weight is low',
                           f'',
                           f'Current dewar weight: {weight:.1f}',
                           f'Estimated weight at 11am fill: {weight_at_fill:.1f}',
                           ]
                    SendEmail.execute({'Subject': f'KPF {dewar} dewar weight is low',
                                       'Message': '\n'.join(msg)})
                except Exception as email_err:
                    log.error(f'Sending email failed')
                    log.error(email_err)

    @classmethod
    def post_condition(cls, args, logger, cfg):
        pass


    @classmethod
    def add_cmdline_args(cls, parser, cfg=None):
        parser.add_argument('dewar', type=str,
                            choices=['green', 'red'],
                            default='green',
                            help='Which dewar to check? red or green')
        parser.add_argument('--email',
                            dest="email",
                            default=False, action="store_true",
                            help='Send email if dewar weight is low')

        return super().add_cmdline_args(parser, cfg)