Month ago, I had a client that requested me to create a Restful API project. I used Flask to deliver the project. But, the problem was how the client can test the project if I don't host the project on a server. To solve the problem, I chose something free like Heroku as this server.
Free Heroku Limitations
There are several limitations in free account Heroku. The most important limitations I've found is we are not able to create an app that involving file upload.
For more limitations, you can see its documentation.
Your Flask Project Setup To Work With Heroku
Install gunicorn Dependency
To work with Heroku, there are several setup you need to do with your Flask App project. First thing first, you need to install gunicorn dependency along side your project. We use gunicorn for Python script to work with Unix server.
To install it, use this pip command :
pip install gunicorn
Create requirements.txt
To create requirements.txt, go to your root project directory. Then, use this command :
pip freeze > requirements.txt
The name of this file must be exact, requirements.txt. Because, Heroku will detect this file automatically. Wrong spelling can cause your app fail to deploy on Heroku.
Create Procfile File
Procfile file is a file that specifies a commands that are executed by the app on the startup. You can save this command on your Procfile file :
web: gunicorn --chdir ./app app:app --reload --workers 4
NOTE : adjust this file according to your project structure
I use additional command --chdir ./app because my I put my app.py inside app folder (app/app.py).
Save the file with exact name, Procfile.
Your Project Structure
The structure of your project can probably like this :
The important files you need to have are Procfile and requirements.txt.
Push Your Project to GitHub
Before we deploy the project to Heroku, we need to push the project to a GitHub repository. So, you need to create your own repo. Then, push your code to that repo. The repo can be public or private.
Setup Your Heroku Project
Now, login to Heroku with your registered account. On your dashboard, click button New > Create new app.
On Create New App page, fill the form with your app name until you get green tick.
Then, click Create App button. After that, you will be redirected to your app dashboard.
On the app dashboard, open Deploy section. On the Deployment method part, select GitHub.
If you haven't connect your Heroku to your GitHub account, you need to connect it before.
After you choose GitHub, you will get Connect to GitHub section. You must choose the repo you want from your GitHub account. If you find it, click Connect button.
The next step is deployment. After successfully connected to GitHub repository, you need to choose what kind of deployment you want.
NOTE : You have two options. Automatic deployment or manual deployment. I suggest, if you are using Heroku free account, you should choose manual deployment as free account has limited number of continuous deployment. So, you can limit your deployment only in case you need it.
Then, select your branch in Manual deploy part. After that, click Deploy Branch. Your deployment process will take several time, just wait for it.
If you get a status like below, this mean your deployment process is successful.
Or, you can check the status on Overview section of your App dashboard on Latest activity.
You can open your app by clicking Open app button on up-right corner.
That's it :)
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