P1 power meter daemon that stuffs data into graphite

p1.py

#!/usr/bin/python
#
# usage: p1-daemon graphite.host.here

import serial
import socket
import sys
import time


ser = serial.Serial(
    '/dev/ttyUSB0',
    baudrate = 9600,
    bytesize = serial.SEVENBITS,
    parity   = serial.PARITY_EVEN,
    stopbits = serial.STOPBITS_ONE,
    xonxoff  = 0,
    rtscts   = 0,
    timeout  = 20,
)
ser.open()

STORE = 'sensor.home'
OBIS = {
    '1.8.1':  'power.recv_t1',
    '1.8.2':  'power.recv_t2',
    '2.8.1':  'power.sent_t1',
    '2.8.2':  'power.sent_t2',
    '1.7.0':  'power.recv_now',
    '2.7.0':  'power.sent_now',
    '24.3.1': 'gas.recv',
}


def write(gram):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.connect((sys.argv[1], 2003))
    n = int(time.time())
    for k in OBIS.values():
        v = gram.get(k, 0)
        metric = '%s %s %d\n' % ('.'.join([STORE, k]), str(v), n)
        print 'gfx', metric.strip()
        s.send(metric)
    s.close()

def update(packet, obis, value):
    print 'upd', obis, value
    if obis in OBIS:
        packet[OBIS[obis]] = value


def decode(gram, line):
    print 'rcv', line
    if line.startswith('/'):  # device identifier
        if gram:
            print 'gram', gram
            write(gram)
        gram = {}

    elif line == '!':
        if gram:
            print 'gram', gram
            write(gram)
        gram = {}

    elif line[3] == ':':
        prefix, blob = line.split(':', 1)
        if '(' in blob:
            obis, data = blob.split('(', 1)
            data = data.rstrip(')').replace('\x00', '')  # wtfnullbytes?
            print 'dat', repr(data)
            if data.endswith('*kWh'):
                update(gram, obis, long(float(data[:-4]) * 1000L))
            elif data.endswith('*kW'):
                update(gram, obis, long(float(data[:-3]) * 1000L))
            else:
                update(gram, obis, data)

    elif line.startswith('('):  # my gas meter reading is on a new line?
        update(gram, '24.3.1', long(float(line[1:-1]) * 1000L))


init = True
gram = {}
while True:
    line = ser.readline().strip('\x00\x0a\x0d\x20')
    print '<<<', repr(line)
    if init:
        if line.startswith('/'):
            init = False
            gram = {}
            print '!!! received initalisation packet'
    elif line == '':
        continue

    else:
        try:
            decode(gram, line)
        except Exception, e:
            print '!!!', str(e)