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Trilochan Parida
Trilochan Parida

Posted on • Updated on

How to Deploy a Flask app on Heroku.

Hello Friends, In this article I will show you how to deploy a flask app on Heroku. Follow the below steps to deploy your python flask app on Heroku.

Prerequisite:

  1. You must have installed Git in your system.
  2. You must have installed Python in your system.

Step-1: Install Heroku CLI

% brew tap heroku/brew && brew install heroku
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Above command is for Mac, for other systems you can click here

Step-2: Create Python Virtual Environment

% python3 -m venv foldername
% source foldername/bin/activate
% cd foldername
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Step-3: Install Flask & Gunicorn

% pip3 install flask gunicorn
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Step-4: Create an app folder and simple python app

% mkdir app
% cd app
% vi main.py
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main.py

from flask import Flask
app= Flask(__name__)
@app.route('/')
def index():
  return "<h1>Welcome to CodingX</h1>"
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Step-5: Create an entry point to the application, wsgi.py

% cd ../
% vi wsgi.py
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wsgi.py

from app.main import app
if __name__ == "__main__":
  app.run()
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Step-6: Run the application in your local system

% python wsgi.py
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Step-7: Create requirements.txt and Procfile file

% pip3 freeze
% pip3 freeze > requirements.txt
% vi Procfile
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Procfile

web: gunicorn wsgi:app
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Step-8: Create an app in Heroku

Heroku new app

Step-9: Deploy your app to heroku

% heroku login
% git init
% heroku git:remote -a codingx-python
% git add.
% git commit -am "First python app"
% git push heroku master
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Step-10: Open your application on browser

https://app-name.herokuapp.com

It's done!

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Discussion (10)

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jnshrink profile image
Jon Nordland

Thank you, Very good. More people should focus on succinct explanations like this.

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techparida profile image
Trilochan Parida Author

I am glad you like it :)

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zeybep profile image
zeybep

Hi,
Firstly thank you very much ... I have to python files and they are in the same folder, named app folder... one is main.py and the other is sendemail1.py and there is wsgi.py file under the virtual directory. But when i run the wsgi.py it gives me the ModuleNotFoundError: No module named 'sendemail1' error so i can not push to heroku...


my wsgi.py is;

from app.main import app

if name == "main":
app.run()


main.py file is:

from flask import Flask, render_template, request
from flask_sqlalchemy import SQLAlchemy
from sendemail1 import sendemail

from sqlalchemy.sql import func
...
app= Flask(name)
app.config['SQLALCHEMY_DATABASE_URI']='postgresql://postgres:123456@localhost/height_collector'

class Data(db.Model):
tablename="data"
id=db.Column(db.Integer,primary_key=True)
email_=db.Column(db.String(120),unique=True)
height_=db.Column(db.Integer)

def __init__(self,email_,height_):
    self.email_=email_
    self.height_=height_
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@app.route("/")
def index():
return render_template("index.html")

@app.route("/success",methods=['POST'])
def success():
if request.method=='POST':
email=request.form["email_name"]
height=request.form["height_name"]

    print(email)
    if  db.session.query(Data).filter(Data.email_ == email).count() == 0:
        data=Data(email,height)
        db.session.add(data)
        db.session.commit()
        #average calculate

        avg_height=db.session.query(func.avg(Data.height_)).scalar()
        avg_height=round(avg_height,1)
        print(avg_height)
        count = db.session.query(Data.height_).count()
        sendemail(email,height,avg_height,count)

        return render_template("success.html")

return render_template("index.html",
text="Seems like there is an email already :)")
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if name=='main':
app.debug=True
app.run()


sendemail1.py file is

from email.mime.text import MIMEText
import smtplib

def sendemail(email,height,avg_height,count):
from_email="usertestblabla@gmail.com"
from_password="eee134566"
to_email=email

subject="Height Data"
message ="Hey , your height is <strong> %s. <strong> Average height of all is %s and calculated out <strong> %s <strong> of people. " % (height, avg_height,count)

msg = MIMEText(message,'html')
msg['Subject']=subject
msg['To']=to_email
msg['From']=from_email

gmail=smtplib.SMTP('smtp.gmail.com',587)
gmail.ehlo()
gmail.starttls()
gmail.login(from_email,from_password)
gmail.send_message(msg)
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thank you very much

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zeybep profile image
zeybep

Hi again,
i found the error...It is because i have to write the import like this
from app.sendemail1 import sendemail to the main.py
than it works
have a great day

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kirtan0000 profile image
Kirtan Magan

Thanks omg you are thebest =ever!!!!1!!!!

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lawrenebrown profile image
Edung Divinefavour

Super useful!!!!!!!!!

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pythondeveloper360 profile image
Hanzala Khan

Hey I have a simple endpoint on my Herokuapp bloggir.herokuapp.com/d and i want to fetch it with JS fetch API, it is giving an error.please help

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mohsinashraf profile image
Mohsin Ashraf

Thanks great tutorial.

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luv2bnanook44 profile image
Luv2bnanook44

thank you!!!

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saragarcia1310 profile image
Sara García

Thank you so much!! Very well explained