twilio queue: python code terminates at SMS message

Question

I have followed multiple YouTube videos in an attempt to create a Twilio queue, the following is my code which is almost identical to the tutorials, however the call queue ends prior to notifying the specified number (via SMS) of a user in the queue. I have commented out the SMS code and the queue app has worked fine. The tutorial videos I referred to are dated over 1 year ago. I have commented out one possible ways of identifying my Account SID and token as I was debugging.

from flask import Flask
from flask import request
from flask import url_for
from twilio import twiml
from twilio.rest import TwilioRestClient
import os

#from flask import render_template

# Declare and configure application
app = Flask(__name__) #, static_url_path='/static')
#app.config.from_pyfile('local_settings.py')


# Configure this number to a toll-free Twilio number to accept incoming calls.
@app.route('/caller', methods=['POST']) #'GET'
def caller():
    response = twiml.Response()
    response.say("Thank you for calling the call center.")
    response.pause(length = "1")
    response.say ("Please hold.")
    response.enqueue("Queue", waitUrl='/wait')
    return str(response)


# Configure waiting room to notify user of current position in the queue and
# play the sweet, soothing sounds of Twilio's coffeeshop collection.
@app.route('/wait', methods=['POST']) #'GET'
def wait():
    response = twiml.Response()
    response.pause(length = "1")
    response.say("You are number %s in the queue." % request.form['QueuePosition'])
    response.play("XXXXXXXXXXXXYYYYYYYYYYYZZZZZZZZZZZZZ")
    ##response.play("http://com.twilio.music.guitars.s3.amazonaws.com/" \
    ##        "Pitx_-_Long_Winter.mp3")
    #client = TwilioRestClient("XXXXXXYYYYYZZZZ","XXXXXXYYYYYYYZZZZ")
    #client.sms.message.create(body="You have a customer waiting in your call center queue. Please call to help.", to="+XYYYYYZZZ", from_="+XXXXXYYYYZZZZ")
    #message = client.messages
    account_sid = "XXXXYYYYZZZ"
    auth_token = "XXXXXYYYYYYZZZZ"
    client = TwilioRestClient(account_sid, auth_token)
    message = client.messages.create("You have a customer waiting in your call center queue. Please call to help.",
    to="+XXXXYYYYZZZZ", # Replace with your phone number
    from_="+XXXXXYYYYZZZZ") # Replace with your Twilio number
    #response.redirect('/wait')
    #print message.sid
    return str(response)


# Connect to support queue - assign to Twilio number for agent to call.
@app.route('/agent', methods=['POST']) #'GET'
def agent():
    response = twiml.Response()
    with response.dial() as dial:
        dial.queue("Queue")
    return str(response)


# If PORT not specified by environment, assume development config.
if __name__ == '__main__':
    port = int(os.environ.get("PORT", 5000))
    #if port == 5000:
    app.debug = True
    app.run(host='0.0.0.0', port=port)

Answer 1

If you reference a 1-2 year old video tutorial, please verify your dependencies are up to date! My Twilio dependency version specified in my Heroku requirements.txt file was not up to date, this outdated dependency was identified as the cause to my initial inquiry (my inability to send sms messages).

There is an option of specifying a "greater than" version of a certain dependency, through the following:

Instead of:

flask==0.9
twilio==3.1

Consider:

flask>=0.9
twilio>=3.1

As the >= syntax will allow you to pull any version greater of that x.x dependecy. Please note there are situations where your project may need a specific older (not-the-most-recent) dependency version.

Which may bring direction towards a virtual environment through the use of virtualenv

Declaring dependencies once activating a virtual environment will allow you to virtually segregate your dependencies and create project specific mutually exclusive dependencies.