sensehat_weather.py

import sys
import time
from argparse import ArgumentParser
from datetime import datetime, timedelta

import gspread
from sense_hat import SenseHat

from logger import get_logger

# logging
logger = get_logger(__name__)


def connect_sensehat():
    hat = SenseHat()
    hat.clear()
    logger.debug("sense hat connected.")
    return hat


def get_readings(hat):
    """Get sensor readings and collate them in a dictionary."""
    readings = {
        "datetime": datetime.now(),
        "temperature": hat.temperature,
        "humidity": hat.humidity,
        "pressure": hat.pressure,
    }
    logger.info("time: {}, temperature: {:.2f}, humidity: {:.2f}, pressure: {:.2f}"
                .format(*[readings[key] for key in ["datetime", "temperature", "humidity", "pressure"]]))

    # round to 2 decimal places for all readings
    for key in readings.copy():
        if key in {"temperature", "humidity", "pressure"}:
            readings[key] = round(readings[key], 2)
    return readings


def convert_sheets_datetime(dt):
    dt_origin = datetime(1899, 12, 30)
    day_seconds = timedelta(days=1).total_seconds()
    dt_sheets = (dt - dt_origin).total_seconds() / day_seconds
    return dt_sheets


def login_open_sheet(credentials_json, spreadsheet_name, worksheet_name):
    """Connect to Google Docs spreadsheet and return the first worksheet."""
    try:
        # connect google account
        gc = gspread.service_account(filename=credentials_json)
        logger.debug("google account authorised.")

        # get worksheet
        worksheet = gc.open(spreadsheet_name).worksheet(worksheet_name)
        logger.debug("google sheet obtained: %s.", worksheet_name)
        return worksheet

    except Exception as e:
        logger.warning("google sheet login failed. "
                       "check OAuth credentials, spreadsheet name, sheet name "
                       "and make sure spreadsheet is shared to the "
                       "client_email address in the OAuth .json file!")
        raise e


def append_readings(worksheet, readings):
    """Append the data in the spreadsheet, including a timestamp."""
    try:
        # convert datetime
        readings["datetime"] = convert_sheets_datetime(readings["datetime"])

        # append readings
        columns = ["datetime", "temperature", "humidity", "pressure"]
        worksheet.append_row([readings.get(col, '') for col in columns])
        logger.debug("readings appended to %s.", worksheet.title)

    except Exception as e:
        # Error appending data, most likely because credentials are stale.
        logger.warning("appending error. credentials are probably stale. "
                       "logging in again.")
        raise e


if __name__ == "__main__":
    arg_parser = ArgumentParser(description="Take readings from SenseHat and add to Google Spreadsheet.")
    arg_parser.add_argument(
        "--credentials-json",
        default="credentials.json",
        help="path to Google OAuth credentials json file (default: %(default)s)"
    )
    arg_parser.add_argument(
        "--spreadsheet",
        default="sensehat-weather",
        help="name of Google Spreadsheet to save SenseHat readings (default: %(default)s)"
    )
    arg_parser.add_argument(
        "--worksheet",
        default="data",
        help="name of worksheet to save SenseHat readings (default: %(default)s)"
    )
    arg_parser.add_argument(
        "--log",
        default="main.log",
        help="path of log file (default: %(default)s)"
    )
    args = arg_parser.parse_args()

    logger = get_logger(__name__, args.log)
    logger.debug("call: %s.", " ".join(sys.argv))
    logger.debug("ArgumentParser: %s.", args)

    # connect sense hat
    hat = connect_sensehat()
    # get sensor readings
    readings = get_readings(hat)
    # upload to google sheet
    for _ in range(30):
        try:
            worksheet = login_open_sheet(args.credentials_json, args.spreadsheet, args.worksheet)
            append_readings(worksheet, readings)
            break
        except Exception as e:
            logger.exception(e)
            time.sleep(240)
            continue