Python Threading Error - Using Raspberry Pi

Question

import fcntl, socket, struct, dweepy, time, platform, random, sqlite3

from grovepi import*

potentiometer = 2 #A2
led = 5 #D5
ultrasonic_ranger = 4 #D4
dht_sensor_port = 7 #D7
Relay_pin = 2 #D2



from threading import Thread

publisher_state = False
publisherrotary_state = False
publishersonic_state = False
publisherhumidity_state = False
def getTemp():

        [temp,humidity] = dht(dht_sensor_port,0)
        return temp

def getultrasonic():
        distant = ultrasonicRead(ultrasonic_ranger)
        return distant

def gethumidity():

        [temp,humidity] = dht(dht_sensor_port,0)
        return humidity

def getrotary():
        i = analogRead(potentiometer)
        return i

def listener(publisher):
    for dweet in dweepy.listen_for_dweets_from('PaulPi'):
        content = dweet["content"]
        should_publish = content["start"]
        print (should_publish)
        if should_publish == "true":
            # start the publisher thread
            global publisher_state
            publisher_state = True
            if not publisher.is_alive():
                publisher = Thread(target=publisher_method_dan)
            publisher.start()
        else:
            publisher_state = False
            print ("wasn't true")

def listenersonic(publishersonic):
    for dweet in dweepy.listen_for_dweets_from('PaulPi3'):
        content = dweet["content"]
        shouldsonic_publish = content["start"]
        print (shouldsonic_publish)
        if shouldsonic_publish == "true":
            # start the publisher thread
            global publishersonic_state
            publishersonic_state = True
            if not publishersonic.is_alive():
                publishersonic = Thread(target=publisher_method_sonic)
            publishersonic.start()
        else:
            publishersonic_state = False
            print ("wasn't true")

def listenerrotary(publisherrotary):
    for dweet in dweepy.listen_for_dweets_from('PaulPi5'):
        content = dweet["content"]
        shouldrotary_publish = content["start"]
        print (shouldrotary_publish)
        if shouldrotary_publish == "true":
            # start the publisher thread
            global publisherrotary_state
            publisherrotary_state = True
            if not publisherrotary.is_alive():
                publisherrotary = Thread(target=publisher_method_rotary)
            publisherrotary.start()
        else:
            publisherrotary_state = False
            print ("wasn't true")

def listenerhumidity(publisherhumidity):
    for dweet in dweepy.listen_for_dweets_from('PaulPi7'):
        content = dweet["content"]
        shouldhumidity_publish = content["start"]
        print (shouldhumidity_publish)
        if shouldhumidity_publish == "true":
            # start the publisher thread
            global publisherhumidity_state
            publisherhumidity_state = True
            if not publisherhumidity.is_alive():
                publisherhumidity = Thread(target=publisher_method_humidity)
            publisherhumidity.start()
        else:
            publisherhumidity_state = False
            print ("wasn't true")

def publish():
    dict = {}
    dict["Temperature"] = 'getTemp'
    dweepy.dweet_for('PaulPi2', dict)

def publishhumidity():
    dict = {}
    dict["humidity"] = 'gethumidity'
    dweepy.dweet_for('PaulPi8', dict)

def publishsonic():
    dict = {}
    dict["ultrasonic"] = 'getultrasonic'
    dweepy.dweet_for('PaulPi4', dict)

def publishrotary():
    dict = {}
    dict["rotary"] = 'getrotary'
    dweepy.dweet_for('PaulPi6', dict)

def publisher_method_dan():
    while publisher_state:
          dict = {}
          dict["Temperature"] = getTemp()
          result =  dweepy.dweet_for('PaulPi2', dict)
          print (result)
          time.sleep(5)
          print ("publishing ending")

def publisher_method_humidity():
    while publisherhumidity_state:
          dict = {}
          dict["humidity"] = gethumidity()
          result =  dweepy.dweet_for('PaulPi8', dict)
          print (result)
          print ("publishing ending")

def publisher_method_sonic():
    while publishersonic_state:
          dict = {}
          dict["ultrasonic"] = getultrasonic()
          result =  dweepy.dweet_for('PaulPi4', dict)
          print (result)
          print ("publishing ending")

def publisher_method_rotary():
    while publisherrotary_state:
          dict = {}
          dict["rotary"] = getrotary()
          result_rotary =  dweepy.dweet_for('PaulPi6', dict)
          print (result_rotary)
          time.sleep(5)
          print ("publishing ending")

publisher_thread = Thread(target=publisher_method_rotary)
listener_thread = Thread(target=listenerrotary, args=(publisher_thread,))
listener_thread.start()

publisher_thread = Thread(target=publisher_method_humidity)
listener_thread = Thread(target=listenerhumidity, args=(publisher_thread,))
listener_thread.start()

publisher_thread = Thread(target=publisher_method_sonic)
listener_thread = Thread(target=listenersonic, args=(publisher_thread,))
listener_thread.start()

publisher_thread = Thread(target=publisher_method_dan)
listener_thread = Thread(target=listener, args=(publisher_thread,))
listener_thread.start()

I'm receiving the following error once i run the python code with my Raspberry Pi, any help would be appreciated as i cannot seem to figure it out.

I am running this off of my Raspberry Pi and Android Phone

The Phone is being used to press buttons to start the sensors and to try receive information from dweet.io. I can see the info on dweet.io but cannot pull the info back to the phone displaying the relevant information.

I am very new to python coding.

Pick one from [python] threads can only be started once

stovfl
– stovfl

2020-03-08 18:27:36 +00:00
Commented Mar 8, 2020 at 18:27 — stovfl
– stovfl, Commented Mar 8, 2020 at 18:27

Shubham Sharma · Accepted Answer · 2020-03-08 18:28:01Z

2

You are getting error because you are trying to start the thread which had already started in the past. If I'm understood correctly, I think you are intending to check whether a thread is alive or not and if it is not alive, you would like to restart it.

To accomplish this,

Replace a code like this:

if not publisherhumidity.is_alive():
    publisherhumidity = Thread(target=publisher_method_humidity)
publisherhumidity.start()

With:

if not publisherhumidity.is_alive():
    publisherhumidity = Thread(target=publisher_method_humidity)
    publisherhumidity.start() #--> place this statement inside if block

answered Mar 8, 2020 at 18:28

Shubham Sharma

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2 Comments

David Hurt Over a year ago

Thanks Shubham, I have indented the code properly and the previous error is gone but now there are new errors. Any thoughts on what might be going on ?

David Hurt Over a year ago

I have added another screenshot of the errors. If you could have a look please

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