def read_publish_sensor_data():
""" Function used to read sensor data and publish the readings to a topic
served by an MQTT server.
"""
# MQTT client publisher
mqtt_publisher = MQTTPublisher()
sensor_serial = ini_config.get("Sensor", "SENSOR_TEMPERATURE_SERIAL")
sleep_timeout = ini_config.getint("Sensor", "SENSOR_SLEEP_TIME")
# start daemon forever loop
while True:
try:
# read and publish sensor reading to topic in MQTT server
logging.debug("publishing sensor serial [{0}] data".format(sensor_serial))
mqtt_publisher.publish_temperature(sensor_serial)
except (Exception) as err:
sys.stderr.write(str(err))
logging.exception("Error reading/publishing sensor data. [{0}]".format(err))
except: # catch *all* other exceptions
err = sys.exc_info()[0]
logging.exception("Error occurred in mqtt daemon: [{0}]".format(err))
write_to_file("<p>Error in mqttpublisher daemon: [{0}]</p>".format(err), sys.stderr)
time.sleep(sleep_timeout)
return
def subscribe_sensor_data():
""" Function used to subscribe to topic destination where sensor readings
are being published.
"""
# MQTT client publisher
mqtt_subscriber = MQTTSubscriber()
sleep_timeout = ini_config.getint("Sensor", "SENSOR_SLEEP_TIME")
# start daemon forever loop
while True:
try:
# read and publish sensor reading to topic in MQTT server
logging.debug("subscribing to sensor TOPIC destination...")
mqtt_subscriber.subscribe_temperature()
except (Exception) as err:
sys.stderr.write(str(err))
logging.exception("Error subscribing to sensor data. [{0}]"
.format(err))
except: # catch *all* other exceptions
err = sys.exc_info()[0]
logging.exception("Error occurred in mqtt daemon: [{0}]"
.format(err))
write_to_file("<p>Error in mqttsubscriber daemon: [{0}]</p>"
.format(err), sys.stderr)
time.sleep(sleep_timeout)
return
def read_store_readings ():
""" Function used to read and store sensor readings
"""
logging.debug("inside read_store_readings...")
if globalFlaskApp is None:
logging.error("Flask has not been initialized!")
raise EnvironmentError("Flask has not been initialized")
# error flag used to send email only once if error occurs.
error_flag = False
headers = {'content-type': 'application/json'}
sensor_url = ini_config.get("Sensor", "SENSOR_TEMPERATURE_URL")
sensor_serial = ini_config.get("Sensor", "SENSOR_TEMPERATURE_SERIAL")
rest_url = (sensor_url + "/" + sensor_serial)
logging.debug("sensor REST URL is [{0}]".format(rest_url))
rest_user = ini_config.get("Sensor", "SENSOR_REST_API_USERNAME")
rest_pw = ini_config.get("Sensor", "SENSOR_REST_API_PASSWORD")
req_timeout = ini_config.getint("Sensor", "SENSOR_REQUEST_TIMEOUT")
sleep_timeout = ini_config.getint("Sensor", "SENSOR_SLEEP_TIME")
recipient = ini_config.get("Email", "RECIPIENT_EMAIL")
with globalFlaskApp.app_context():
logging.debug("starting forever loop within Flask app context")
# start daemon forever loop
while True:
try:
# collect data from sensor using RESTFul API
logging.debug("Sending request to [{0}] with user [{1}]"
.format(rest_url, rest_user))
r = requests.get(rest_url,
verify=False,
auth=(rest_user, rest_pw),
headers=headers,
timeout=req_timeout)
# if code gets here no exception has occurred. reset flag.
error_flag = False
if (r.status_code != 200):
logging.error("Response status code [{0}] : [{1}]"
.format(r.status_code, r.text))
else:
output = r.json()
sensor = output[SENSOR_KEY]
readings = output[DATA_KEY]
logging.debug("Adding sensor record with unit [{0}], "
"value [{1}], utc [{2}], serial [{3}] to "
"database."
.format(readings["unit"],
readings["value"],
readings["utc"],
sensor["serial"]))
SensorDAO.add_reading(readings["unit"],
readings["value"],
readings["utc"],
sensor["serial"])
# python 3.4: ConnectionRefusedError
except (ConnectionError, Timeout) as err: # e.g., server is down.
sys.stderr.write(str(err))
logging.exception("Connection Error with URL [{0}], "
"user [{1}] in runserver daemon: [{2}]"
.format(rest_url, rest_user, err))
if not error_flag : # only send email once.
subject = "sensorserver: Connection/Timeout Error"
logging.info("Sending email to [{0}] with subject [{1}]"
.format(recipient, subject))
message = ("Connection/Timeout Error to URL [{0}]: [{1}]"
.format(rest_url, err))
try:
EMail.send_email(recipient, subject, message)
logging.info("email to [{0}] with subject [{1}] sent."
.format(recipient, subject))
except Exception as mail_err:
logging.error("Error [{0}] sending email."
.format(mail_err))
error_flag = True
except (HTTPError, RequestException) as err:
sys.stderr.write(str(err))
logging.exception("HTTP/Request Error to URL [{0}] in "
"runserver daemon: [{1}]"
.format(rest_url, err))
if not error_flag : # only send email once.
subject = "sensorserver: HTTP Error"
logging.info("Sending email to [{0}] with subject [{1}]"
.format(recipient, subject))
message = ("HTTP/Request to URL [{0}] Error: [{1}]"
.format(rest_url, err))
try:
EMail.send_email(recipient, subject, message)
logging.info(
"email to [{0}] with subject [{1}] was sent."
.format(recipient, subject))
except Exception as mail_err:
logging.error("Error [{0}] sending email."
.format(mail_err))
error_flag = True
except (EnvironmentError, Exception) as err:
sys.stderr.write(str(err))
logging.exception("Error in runserver daemon: [{0}]"
.format(err))
if not error_flag : # only send email once.
subject = "sensorserver: Environment Error"
logging.info("Sending email to [{0}] with subject [{1}]"
.format(recipient, subject))
message = "EXITING APPLICATION. Error: [{0}]".format(err)
try:
EMail.send_email(recipient, subject, message)
logging.info(
"email to [{0}] with subject [{1}] was sent."
.format(recipient, subject))
except Exception as mail_err:
logging.error("Error [{0}] sending email."
.format(mail_err))
error_flag = True
except: # catch *all* other exceptions
err = sys.exc_info()[0]
logging.exception("Error occurred in runserver daemon: [{0}]"
.format(err))
write_to_file("<p>Error in runsensor daemon: [{0}]</p>"
.format(err), sys.stderr)
exit(1)
time.sleep(sleep_timeout)
return