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):
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:
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