[Python] Flask app with flask-ngrok stuck in Colab (no public URL, cell runs indefinitely,...

I'm trying to run a simple Flask chatbot app in Google Colab, using flask-ngrok to expose it publicly. I began developing locally but I ran into some Tensorflow import issues and moved to Colab. However, even after installing flask-ngrok and setting my ngrok authtoken, the cell hangs and only shows:

• Running on http://127.0.0.1:5000

(along with a ton of other nonsense error log messages.)

I don't get the "https://xxxx.ngrok.io" public URL, and when I try to visit 127.0.0.1 link, I get: "Access to 127.0.0.1 was denied, HTTP ERROR 403"

I have already done these things:

1.) Restarted the Colab runtime

2.) Installed both flask-ngrok and pyngrok==4.1.1

3.) Set my ngrok authtoken (confirmed it's from the ngrok dashboard)

Here is my code:

!pip install flask pyngrok
from pyngrok import ngrok
ngrok.set_auth_token("my_auth_token")


from flask import Flask, request, jsonify, render_template

from pyngrok import ngrok
import threading

app = Flask(__name__, template_folder='templates')
app.debug = False
run_with_ngrok(app)

@app.route("/")
def index():
return render_template("index.html")

@app.route('/handle_message', methods=['POST'])
def handle_message():
message = request.json['message']
intents_list = predict_class(message)
response = get_response(intents_list, intents)
return jsonify({'response': response})

if __name__ == "__main__":
app.run()

public_url = ngrok.connect(5000)
print(f"Your app is live at: {public_url}")

thread = threading.Thread(target=run_flask)
thread.start()


Even after doing all of this, Colab gets stuck on 127.0.0.1 with extremely messy logs, and I don’t get a public URL from ngrok.

I just to run a simple Flask app in Colab and get a public ngrok URL so I can test a chatbot UI with /handle_message.

Has anyone been able to successfully run Flask with ngrok in Colab recently? Am I missing something about flask-ngrok or ngrok auth config in Colab?

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