app.py

from flask import Flask, render_template
import os
import random

app = Flask(__name__)

# list of cat images
images = [
    "https://firebasestorage.googleapis.com/v0/b/docker-curriculum.appspot.com/o/catnip%2F0.gif?alt=media&token=0fff4b31-b3d8-44fb-be39-723f040e57fb",
    "https://firebasestorage.googleapis.com/v0/b/docker-curriculum.appspot.com/o/catnip%2F1.gif?alt=media&token=2328c855-572f-4a10-af8c-23a6e1db574c",
    "https://firebasestorage.googleapis.com/v0/b/docker-curriculum.appspot.com/o/catnip%2F10.gif?alt=media&token=647fd422-c8d1-4879-af3e-fea695da79b2",
    "https://firebasestorage.googleapis.com/v0/b/docker-curriculum.appspot.com/o/catnip%2F11.gif?alt=media&token=900cce1f-55c0-4e02-80c6-ee587d1e9b6e",
    "https://firebasestorage.googleapis.com/v0/b/docker-curriculum.appspot.com/o/catnip%2F2.gif?alt=media&token=8a108bd4-8dfc-4dbc-9b8c-0db0e626f65b",
    "https://firebasestorage.googleapis.com/v0/b/docker-curriculum.appspot.com/o/catnip%2F3.gif?alt=media&token=4e270d85-0be3-4048-99bd-696ece8070ea",
    "https://firebasestorage.googleapis.com/v0/b/docker-curriculum.appspot.com/o/catnip%2F4.gif?alt=media&token=e7daf297-e615-4dfc-aa19-bee959204774",
    "https://firebasestorage.googleapis.com/v0/b/docker-curriculum.appspot.com/o/catnip%2F5.gif?alt=media&token=a8e472e6-94da-45f9-aab8-d51ec499e5ed",
    "https://firebasestorage.googleapis.com/v0/b/docker-curriculum.appspot.com/o/catnip%2F7.gif?alt=media&token=9e449089-9f94-4002-a92a-3e44c6bd18a9",
    "https://firebasestorage.googleapis.com/v0/b/docker-curriculum.appspot.com/o/catnip%2F8.gif?alt=media&token=80a48714-7aaa-45fa-a36b-a7653dc3292b",
    "https://firebasestorage.googleapis.com/v0/b/docker-curriculum.appspot.com/o/catnip%2F9.gif?alt=media&token=a57a1c71-a8af-4170-8fee-bfe11809f0b3",
]


@app.route("/")
def index():
    url = random.choice(images)
    return render_template("index.html", url=url)


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=int(os.environ.get("PORT", 80)))