MyEMS / myems

myems-normalization/virtualmeter.py

import random
import time
from datetime import datetime, timedelta
from decimal import Decimal
from multiprocessing import Pool
import mysql.connector
from sympy import sympify
import config


########################################################################################################################
# PROCEDURES:
# Step 1: Query all virtual meters
# Step 2: Create multiprocessing pool to call worker in parallel
########################################################################################################################

def calculate_hourly(logger):

This code seems to be duplicated in your project.

    while True:
        # the outermost while loop to reconnect server if there is a connection error
        cnx_system_db = None
        cursor_system_db = None
        try:
            cnx_system_db = mysql.connector.connect(**config.myems_system_db)
            cursor_system_db = cnx_system_db.cursor()
        except Exception as e:
            logger.error("Error in step 0 of virtual_meter.calculate_hourly " + str(e))
            if cursor_system_db:
                cursor_system_db.close()
            if cnx_system_db:
                cnx_system_db.close()
            # sleep and continue the outer loop to reconnect the database
            time.sleep(60)
            continue

        print("Connected to MyEMS System Database")

        virtual_meter_list = list()
        try:
            cursor_system_db.execute(" SELECT id, name, equation "
                                     " FROM tbl_virtual_meters "
                                     " ORDER BY id ")
            rows_virtual_meters = cursor_system_db.fetchall()

            if rows_virtual_meters is None or len(rows_virtual_meters) == 0:
                # sleep several minutes and continue the outer loop to reconnect the database
                time.sleep(60)
                continue

            for row in rows_virtual_meters:
                meta_result = {"id": row[0], "name": row[1], "equation": row[2]}
                virtual_meter_list.append(meta_result)

        except Exception as e:
            logger.error("Error in step 1 of virtual meter calculate hourly " + str(e))
            # sleep and continue the outer loop to reconnect the database
            time.sleep(60)
            continue
        finally:
            if cursor_system_db:
                cursor_system_db.close()
            if cnx_system_db:
                cnx_system_db.close()

        # shuffle the virtual meter list for randomly calculating the meter hourly value
        random.shuffle(virtual_meter_list)

        print("Got all virtual meters in MyEMS System Database")
        ################################################################################################################
        # Step 2: Create multiprocessing pool to call worker in parallel
        ################################################################################################################
        p = Pool(processes=config.pool_size)
        error_list = p.map(worker, virtual_meter_list)
        p.close()
        p.join()

        for error in error_list:
            if error is not None and len(error) > 0:
                logger.error(error)

        print("go to sleep ...")
        time.sleep(60)
        print("wake from sleep, and continue to work...")


########################################################################################################################
# Step 1: get start datetime and end datetime
# Step 2: parse the expression and get all meters, virtual meters, offline meters associated with the expression
# Step 3: query energy consumption values from table meter hourly, virtual meter hourly and offline meter hourly
# Step 4: evaluate the equation with variables values from previous step and save to table virtual meter hourly
# returns the error string for logging or returns None
########################################################################################################################

def worker(virtual_meter):
    cnx_energy_db = None
    cursor_energy_db = None

    try:
        cnx_energy_db = mysql.connector.connect(**config.myems_energy_db)
        cursor_energy_db = cnx_energy_db.cursor()
    except Exception as e:
        if cursor_energy_db:
            cursor_energy_db.close()
        if cnx_energy_db:
            cnx_energy_db.close()
        return "Error in step 1.1 of virtual meter worker " + str(e) + " for '" + virtual_meter['name'] + "'"

    print("Start to process virtual meter: " + "'" + virtual_meter['name']+"'")

    ####################################################################################################################
    # step 1: get start datetime and end datetime
    #         get latest timestamp from energy database in tbl_virtual_meter_hourly
    ####################################################################################################################

    try:
        query = (" SELECT MAX(start_datetime_utc) "
                 " FROM tbl_virtual_meter_hourly "
                 " WHERE virtual_meter_id = %s ")
        cursor_energy_db.execute(query, (virtual_meter['id'],))
        row_datetime = cursor_energy_db.fetchone()
    except Exception as e:
        if cursor_energy_db:
            cursor_energy_db.close()
        if cnx_energy_db:
            cnx_energy_db.close()
        return "Error in step 1.2 of virtual meter worker " + str(e) + " for '" + virtual_meter['name'] + "'"

    start_datetime_utc = datetime.strptime(config.start_datetime_utc, '%Y-%m-%d %H:%M:%S')
    start_datetime_utc = start_datetime_utc.replace(minute=0, second=0, microsecond=0, tzinfo=None)

    if row_datetime is not None and len(row_datetime) > 0 and isinstance(row_datetime[0], datetime):
        # replace second and microsecond with 0
        # note: do not replace minute in case of calculating in half hourly
        start_datetime_utc = row_datetime[0].replace(second=0, microsecond=0, tzinfo=None)
        # start from the next time slot
        start_datetime_utc += timedelta(minutes=config.minutes_to_count)

    end_datetime_utc = datetime.utcnow().replace()
    end_datetime_utc = end_datetime_utc.replace(second=0, microsecond=0, tzinfo=None)

    time_difference = end_datetime_utc - start_datetime_utc
    time_difference_in_minutes = time_difference / timedelta(minutes=1)
    if time_difference_in_minutes < config.minutes_to_count:
        if cursor_energy_db:
            cursor_energy_db.close()
        if cnx_energy_db:
            cnx_energy_db.close()
        return "it isn't time to calculate" + " for '" + virtual_meter['name'] + "'"
    elif time_difference_in_minutes > 60 * 24 * 30:
        # avoid to caculate records more than one month
        end_datetime_utc = start_datetime_utc + timedelta(minutes=60 * 24 * 30)

    # trim end_datetime_utc
    trimmed_end_datetime_utc = start_datetime_utc + timedelta(minutes=config.minutes_to_count)
    while trimmed_end_datetime_utc <= end_datetime_utc:
        trimmed_end_datetime_utc += timedelta(minutes=config.minutes_to_count)

    end_datetime_utc = trimmed_end_datetime_utc - timedelta(minutes=config.minutes_to_count)

    if end_datetime_utc <= start_datetime_utc:
        if cursor_energy_db:
            cursor_energy_db.close()
        if cnx_energy_db:
            cnx_energy_db.close()
        return "it isn't time to calculate" + " for '" + virtual_meter['name'] + "'"

    print("start_datetime_utc: " + start_datetime_utc.isoformat()[0:19]
          + "end_datetime_utc: " + end_datetime_utc.isoformat()[0:19])

    ############################################################################################################
    # Step 2: parse the expression and get all meters, virtual meters, and
    #         offline meters associated with the expression
    ############################################################################################################
    cnx_system_db = None
    cursor_system_db = None
    try:
        cnx_system_db = mysql.connector.connect(**config.myems_system_db)
        cursor_system_db = cnx_system_db.cursor()
    except Exception as e:
        if cursor_system_db:
            cursor_system_db.close()
        if cnx_system_db:
            cnx_system_db.close()
        if cursor_energy_db:
            cursor_energy_db.close()
        if cnx_energy_db:
            cnx_energy_db.close()
        return "Error in step 2.1 of virtual meter worker " + str(e) + " for '" + virtual_meter['name'] + "'"

    meter_list_in_expression = list()
    virtual_meter_list_in_expression = list()
    offline_meter_list_in_expression = list()
    try:
        ########################################################################################################
        # get all meters associated with the expression
        ########################################################################################################

        cursor_system_db.execute(" SELECT m.id as meter_id, v.name as variable_name "
                                 " FROM tbl_meters m, tbl_variables v "
                                 " WHERE m.id = v.meter_id "
                                 "       AND v.meter_type = 'meter' "
                                 "       AND v.virtual_meter_id = %s ",
                                 (virtual_meter['id'], ))
        rows = cursor_system_db.fetchall()
        if rows is not None and len(rows) > 0:
            for row in rows:
                meter_list_in_expression.append({"meter_id": row[0], "variable_name": row[1].lower()})

        ########################################################################################################
        # get all virtual meters associated with the expression
        ########################################################################################################

        cursor_system_db.execute(" SELECT m.id as virtual_meter_id, v.name as variable_name "
                                 " FROM tbl_virtual_meters m, tbl_variables v "
                                 " WHERE m.id = v.meter_id "
                                 "       AND v.meter_type = 'virtual_meter' "
                                 "       AND v.virtual_meter_id = %s ",
                                 (virtual_meter['id'],))
        rows = cursor_system_db.fetchall()
        if rows is not None and len(rows) > 0:
            for row in rows:
                virtual_meter_list_in_expression.append({"virtual_meter_id": row[0],
                                                         "variable_name": row[1].lower()})

        ########################################################################################################
        # get all offline meters associated with the expression
        ########################################################################################################

        cursor_system_db.execute(" SELECT m.id as offline_meter_id, v.name as variable_name "
                                 " FROM tbl_offline_meters m, tbl_variables v "
                                 " WHERE m.id = v.meter_id "
                                 "       AND v.meter_type = 'offline_meter' "
                                 "       AND v.virtual_meter_id = %s ",
                                 (virtual_meter['id'],))
        rows = cursor_system_db.fetchall()
        if rows is not None and len(rows) > 0:
            for row in rows:
                offline_meter_list_in_expression.append({"offline_meter_id": row[0],
                                                         "variable_name": row[1].lower()})
    except Exception as e:
        if cursor_energy_db:
            cursor_energy_db.close()
        if cnx_energy_db:
            cnx_energy_db.close()
        return "Error in step 2.2 of virtual meter worker " + str(e) + " for '" + virtual_meter['name'] + "'"
    finally:
        if cursor_system_db:
            cursor_system_db.close()
        if cnx_system_db:
            cnx_system_db.close()

    ############################################################################################################
    # Step 3: query energy consumption values from table meter hourly, virtual meter hourly
    #         and offline meter hourly
    ############################################################################################################

    print("getting energy consumption values from myems_energy_db.tbl_meter_hourly...")
    energy_meter_hourly = dict()
    if meter_list_in_expression is not None and len(meter_list_in_expression) > 0:
        try:
            for meter_in_expression in meter_list_in_expression:
                meter_id = str(meter_in_expression['meter_id'])
                query = (" SELECT start_datetime_utc, actual_value "
                         " FROM tbl_meter_hourly "
                         " WHERE meter_id = %s AND start_datetime_utc >= %s AND start_datetime_utc < %s "
                         " ORDER BY start_datetime_utc ")
                cursor_energy_db.execute(query, (meter_id, start_datetime_utc, end_datetime_utc, ))
                rows_energy_values = cursor_energy_db.fetchall()
                if rows_energy_values is None or len(rows_energy_values) == 0:
                    energy_meter_hourly[meter_id] = None
                else:
                    energy_meter_hourly[meter_id] = dict()
                    for row_energy_value in rows_energy_values:
                        energy_meter_hourly[meter_id][row_energy_value[0]] = row_energy_value[1]
        except Exception as e:
            if cursor_energy_db:
                cursor_energy_db.close()
            if cnx_energy_db:
                cnx_energy_db.close()
            return "Error in step 3.2 virtual meter worker " + str(e) + " for '" + virtual_meter['name'] + "'"

    print("getting energy consumption values from myems_energy_db.tbl_virtual_meter_hourly...")
    energy_virtual_meter_hourly = dict()
    if virtual_meter_list_in_expression is not None and len(virtual_meter_list_in_expression) > 0:
        try:
            for virtual_meter_in_expression in virtual_meter_list_in_expression:
                virtual_meter_id = str(virtual_meter_in_expression['virtual_meter_id'])
                query = (" SELECT start_datetime_utc, actual_value "
                         " FROM tbl_virtual_meter_hourly "
                         " WHERE virtual_meter_id = %s "
                         "       AND start_datetime_utc >= %s AND start_datetime_utc < %s "
                         " ORDER BY start_datetime_utc ")
                cursor_energy_db.execute(query, (virtual_meter_id, start_datetime_utc, end_datetime_utc,))
                rows_energy_values = cursor_energy_db.fetchall()
                if rows_energy_values is None or len(rows_energy_values) == 0:
                    energy_virtual_meter_hourly[virtual_meter_id] = None
                else:
                    energy_virtual_meter_hourly[virtual_meter_id] = dict()
                    for row_energy_value in rows_energy_values:
                        energy_virtual_meter_hourly[virtual_meter_id][row_energy_value[0]] = row_energy_value[1]
        except Exception as e:
            if cursor_energy_db:
                cursor_energy_db.close()
            if cnx_energy_db:
                cnx_energy_db.close()
            return "Error in step 3.3 virtual meter worker " + str(e) + " for '" + virtual_meter['name'] + "'"

    print("getting energy consumption values from myems_energy_db.tbl_offline_meter_hourly...")
    energy_offline_meter_hourly = dict()
    if offline_meter_list_in_expression is not None and len(offline_meter_list_in_expression) > 0:
        try:
            for offline_meter_in_expression in offline_meter_list_in_expression:
                offline_meter_id = str(offline_meter_in_expression['offline_meter_id'])
                query = (" SELECT start_datetime_utc, actual_value "
                         " FROM tbl_offline_meter_hourly "
                         " WHERE offline_meter_id = %s "
                         "       AND start_datetime_utc >= %s AND start_datetime_utc < %s "
                         " ORDER BY start_datetime_utc ")
                cursor_energy_db.execute(query, (offline_meter_id, start_datetime_utc, end_datetime_utc,))
                rows_energy_values = cursor_energy_db.fetchall()
                if rows_energy_values is None or len(rows_energy_values) == 0:
                    energy_offline_meter_hourly[offline_meter_id] = None
                else:
                    energy_offline_meter_hourly[offline_meter_id] = dict()
                    for row_energy_value in rows_energy_values:
                        energy_offline_meter_hourly[offline_meter_id][row_energy_value[0]] = row_energy_value[1]
        except Exception as e:
            if cursor_energy_db:
                cursor_energy_db.close()
            if cnx_energy_db:
                cnx_energy_db.close()
            return "Error in step 3.4 virtual meter worker " + str(e) + " for '" + virtual_meter['name'] + "'"

    ############################################################################################################
    # Step 4: evaluate the equation with variables values from previous step
    #         and save to table virtual meter hourly
    ############################################################################################################

    print("getting common time slot of energy values for all meters...")
    common_start_datetime_utc = start_datetime_utc
    common_end_datetime_utc = end_datetime_utc
    if energy_meter_hourly is not None and len(energy_meter_hourly) > 0:
        for meter_id, energy_hourly in energy_meter_hourly.items():
            if energy_hourly is None or len(energy_hourly) == 0:
                common_start_datetime_utc = None
                common_end_datetime_utc = None
                break
            else:
                if common_start_datetime_utc < min(energy_hourly.keys()):
                    common_start_datetime_utc = min(energy_hourly.keys())
                if common_end_datetime_utc > max(energy_hourly.keys()):
                    common_end_datetime_utc = max(energy_hourly.keys())

    print("getting common time slot of energy values for all virtual meters...")
    if common_start_datetime_utc is not None and common_end_datetime_utc is not None:
        if energy_virtual_meter_hourly is not None and len(energy_virtual_meter_hourly) > 0:
            for meter_id, energy_hourly in energy_virtual_meter_hourly.items():
                if energy_hourly is None or len(energy_hourly) == 0:
                    common_start_datetime_utc = None
                    common_end_datetime_utc = None
                    break
                else:
                    if common_start_datetime_utc < min(energy_hourly.keys()):
                        common_start_datetime_utc = min(energy_hourly.keys())
                    if common_end_datetime_utc > max(energy_hourly.keys()):
                        common_end_datetime_utc = max(energy_hourly.keys())

    print("getting common time slot of energy values for all offline meters...")
    if common_start_datetime_utc is not None and common_end_datetime_utc is not None:
        if energy_offline_meter_hourly is not None and len(energy_offline_meter_hourly) > 0:
            for meter_id, energy_hourly in energy_offline_meter_hourly.items():
                if energy_hourly is None or len(energy_hourly) == 0:
                    common_start_datetime_utc = None
                    common_end_datetime_utc = None
                    break
                else:
                    if common_start_datetime_utc < min(energy_hourly.keys()):
                        common_start_datetime_utc = min(energy_hourly.keys())
                    if common_end_datetime_utc > max(energy_hourly.keys()):
                        common_end_datetime_utc = max(energy_hourly.keys())

    print("evaluating the equation with SymPy...")
    normalized_values = list()

    ############################################################################################################
    # Converting Strings to SymPy Expressions
    # The sympify function(that’s sympify, not to be confused with simplify) can be used to
    # convert strings into SymPy expressions.
    ############################################################################################################
    try:
        expr = sympify(virtual_meter['equation'].lower())
        print("the expression to be evaluated: " + str(expr))
        current_datetime_utc = common_start_datetime_utc
        print("common_start_datetime_utc: " + str(common_start_datetime_utc))
        print("common_end_datetime_utc: " + str(common_end_datetime_utc))
        while common_start_datetime_utc is not None \
                and common_end_datetime_utc is not None \
                and current_datetime_utc <= common_end_datetime_utc:
            meta_data = dict()
            meta_data['start_datetime_utc'] = current_datetime_utc

            ####################################################################################################
            # create a dictionary of Symbol: point pairs
            ####################################################################################################

            subs = dict()

            ####################################################################################################
            # Evaluating the expression at current_datetime_utc
            ####################################################################################################

            if meter_list_in_expression is not None and len(meter_list_in_expression) > 0:
                for meter_in_expression in meter_list_in_expression:
                    meter_id = str(meter_in_expression['meter_id'])
                    actual_value = energy_meter_hourly[meter_id].get(current_datetime_utc, Decimal(0.0))
                    subs[meter_in_expression['variable_name']] = actual_value

            if virtual_meter_list_in_expression is not None and len(virtual_meter_list_in_expression) > 0:
                for virtual_meter_in_expression in virtual_meter_list_in_expression:
                    virtual_meter_id = str(virtual_meter_in_expression['virtual_meter_id'])
                    actual_value = energy_virtual_meter_hourly[virtual_meter_id].get(current_datetime_utc, Decimal(0.0))
                    subs[virtual_meter_in_expression['variable_name']] = actual_value

            if offline_meter_list_in_expression is not None and len(offline_meter_list_in_expression) > 0:
                for offline_meter_in_expression in offline_meter_list_in_expression:
                    offline_meter_id = str(offline_meter_in_expression['offline_meter_id'])
                    actual_value = energy_offline_meter_hourly[offline_meter_id].get(current_datetime_utc, Decimal(0.0))
                    subs[offline_meter_in_expression['variable_name']] = actual_value

            ####################################################################################################
            # To numerically evaluate an expression with a Symbol at a point,
            # we might use subs followed by evalf,
            # but it is more efficient and numerically stable to pass the substitution to evalf
            # using the subs flag, which takes a dictionary of Symbol: point pairs.
            ####################################################################################################

            meta_data['actual_value'] = expr.evalf(subs=subs)

            normalized_values.append(meta_data)

            current_datetime_utc += timedelta(minutes=config.minutes_to_count)

    except Exception as e:
        if cursor_energy_db:
            cursor_energy_db.close()
        if cnx_energy_db:
            cnx_energy_db.close()
        return "Error in step 4.1 virtual meter worker " + str(e) + " for '" + virtual_meter['name'] + "'"

    print("saving energy values to table energy virtual meter hourly...")

    while len(normalized_values) > 0:

This code seems to be duplicated in your project.

        insert_100 = normalized_values[:100]
        normalized_values = normalized_values[100:]
        try:
            add_values = (" INSERT INTO tbl_virtual_meter_hourly "
                          " (virtual_meter_id, start_datetime_utc, actual_value) "
                          " VALUES  ")

            for meta_data in insert_100:
                add_values += " (" + str(virtual_meter['id']) + ","
                add_values += "'" + meta_data['start_datetime_utc'].isoformat()[0:19] + "',"
                add_values += str(meta_data['actual_value']) + "), "
            print("add_values:" + add_values)
            # trim ", " at the end of string and then execute
            cursor_energy_db.execute(add_values[:-2])
            cnx_energy_db.commit()
        except Exception as e:
            if cursor_energy_db:
                cursor_energy_db.close()
            if cnx_energy_db:
                cnx_energy_db.close()
            return "Error in step 4.2 virtual meter worker " + str(e) + " for '" + virtual_meter['name'] + "'"

    if cursor_energy_db:
        cursor_energy_db.close()
    if cnx_energy_db:
        cnx_energy_db.close()

    return None