Heroku¶

Heroku is a “platform as a service (PaaS) that enables developers to build, run, and operate applications entirely in the cloud.” Heroku even offers a free plan.

Here’s how to deploy your implementation of, say, C$50 Finance to Heroku from GitHub.

Watch Brian’s seminar to learn about git and GitHub, if not already familiar.
Sign up for free, private GitHub repositories at https://education.github.com/discount_requests/new, if you haven’t already.
Create a new private repository at https://github.com/new (called, e.g., finance).
Take note of the HTTPS URL of the repository (e.g., https://github.com/username/finance.git, where username is your own GitHub username).
Change to your implementation’s directory on CS50 IDE.
```
cd ~/pset8/finance/
```
Create a git repo therein.
```
git init
```
Add the GitHub repository as a “remote,” where username is your own GitHub username.
```
git remote add origin https://github.com/username/finance.git
```
In the requirements.txt file inside of your finance directory, add gunicorn and psycopg2, each on separate lines.
Push your code to GitHub.
```
git add -A
git commit -m "first commit"
git push -u origin master
```
If you visit https://github.com/username/finance, where username is your own GitHub username, you should see your code in the repository.
Sign up for a free Heroku account at https://signup.heroku.com/, if you don’t have one already.
Create a new app at https://dashboard.heroku.com/new-app.
Configure your app at https://dashboard.heroku.com/apps/app-name/deploy/github, where app-name is your Heroku app’s name.
- Add this app to a pipeline: No need to configure; leave as is.
- Deployment method: Select GitHub, then click Connect to GitHub. If prompted to log into GitHub, click Authorize heroku.
- App connected to GitHub: Search for your app’s repository (e.g., username/finance, where username is your own GitHub username), then click Connect.
- Automatic deploys: Click Enable Automatic Deploys.
Search for and provision Heroku Postgres at https://dashboard.heroku.com/apps/app-name/resources, where app-name is your Heroku app’s name; select a Plan name of Hobby Dev — Free.
At https://dashboard.heroku.com/apps/app-name/resources, where app-name is your Heroku app’s name, click Heroku Postgres :: Database. In the tab that opens, click Settings, then click View Credentials…. Highlight and copy the URI that appears.
In CS50 IDE, open application.py in ~/pset8/finance/ and find:
```
db = SQL("sqlite:///finance.db")
```
Replace sqlite:///finance.db with that URI (so that the CS50 Library will connect to your Postgres database instead of your SQLite database).
In CS50 IDE, execute the below to import finance.db into your Postgres database, where URI is that same URI. Be sure to append ?sslmode=require to the URI.
```
pgloader finance.db URI?sslmode=require
```
Thereafter, if you’d like to browse or edit your Postgres database, you can use Adminer (a tool like phpLiteAdmin for Postgres databases), at adminer.cs50.net. Log in using your database’s credentials: at https://dashboard.heroku.com/apps/app-name/resources, where app-name is your Heroku app’s name, click Heroku Postgres :: Database. In the tab that opens, click Settings, then click View Credentials….
Create a new file in CS50 IDE called Procfile in ~/pset8/finance/ whose contents are:
```
web: gunicorn application:app
```
That file will tell Heroku to look in a file called application.py for a variable called app and serve it with Gunicorn, a production-quality web server. (Flask’s built-in web server is “good enough for testing but probably not what you want to use in production.”)
Add that file to your repository and push it to GitHub.
```
git add -A
git commit -m "added Procfile"
git push
```
If you visit https://app-name.herokuapp.com/, where app-name is your Heroku app’s name, you should see your app! If you instead see some error, visit https://dashboard.heroku.com/apps/app-name/logs, where app-name is your app’s name, to diagnose! Each time you add (new or changed) files to your repository and push to GitHub hereafter, your app will be re-deployed to Heroku.