Deploy to Heroku with Express

[codessi]

Express Deployment with Heroku

You've learned a lot about how to build a Node application over the last
few weeks. Now let's 'go public' and share our apps with the world!

Prerequisites

• Express Api
• This guide assumes you have followed
  these installation instructions
  unequivocally.
• Heroku Account and Toolbelt CLI

Objectives

• Create a Heroku app from the command line.
• Push the latest code to Heroku.
• Set up MongoDB Atlas
• Add environment variables
• Share a link to your app.

Deploying to Heroku

Begin inside the root directory of your application (the directory you
just renamed to express-upload-api from express-api-template) deploy a new
application to Heroku:

• Run heroku create in the command line in the root of your Express API to
  create a new (blank) app on Heroku.
• Commit to your local main branch
  (if you do not have a branch named main, you can create one with git checkout -b main)
• Push your latest code to Heroku (git push heroku main)
• Add any addons
  • If using MongoDB you'll need to follow the atlas add on steps
  • If using AWS you'll need to follow the aws credentials steps
• In terminal, run: git push heroku main (should build your site)
• Due to the first line of code in the server.js file, the default
  deployment environment will be production
• You need to set your CLIENT_ORIGIN so that your deployed API will ONLY
  accept requests from the correct domain. IF you're client is deployed on GitHub,
  your ORIGIN will be:
  https://<% github username %>.github.io
• Set your client ORIGIN by:
  heroku config:set CLIENT_ORIGIN="https://<% github username %>.github.io"
• You should have (at least) two config variables set in heroku
  (heroku>settings>config vars): DB_URI and CLIENT_ORIGIN
  • If you are using AWS, you should have two additional config variables.
• Once all of these are set, run in terminal: heroku restart
• Then in terminal, run: heroku open

NOTE: heroku open will open your deployed Express API in the browser. It will most likely be a blank white page that says Cannot GET /. This is expected since you probably did not create a route for the path /. To verify your deployment worked, you can change the path in the URL to match a valid route you did define in your app (e.g. if I have a GET route for /books, I should see some JSON when I add /books to the URL).

A full list of Heroku commands can be accessed by running heroku --help

Share Your App (REQUIRED)

1. Fork and clone this repository.
2. Change into the new directory.
3. Create and checkout a new branch, named response.
4. Delete the contents of deployedUrl.txt with the URL of your
   deployed heroku application.
5. Add, commit, and push your changes.
6. Open a PR on this repository here.

Your pull request description should contain a "fist to five" for comfort and
clarity. Additionally, you should mention the resources you used to help you
complete this guide. For example:

Comfort: 3
Clarity: 3

I used Google and my class notes to help with this exercise.

You may wish to refer to FAQs
related to
forking,
cloning,
and pull requests.

Creating Atlas addon

• Go to https://cloud.mongodb.com/ and sign in
• Since the free-tier of MongoDB Atlas only allows one cluster
  per project, create a new project and a new cluster, selecting the "Free" version
• Once the cluster has been created, click "connect" on the cluster overview
• Setup connection security:
  • For "step 1: Add a connection IP address", select Allow Access From Anywhere
  • Create a user, admin, with a password. Save these credentials
    somewhere safe.
• Choose a connection method:
  • Select "Connect your application"
  • Select "Node.js" as the driver, version 3.6 or later
  • Copy the connection string provided
• In terminal, run heroku config:set DB_URI="<your-connection-string>",
  replacing the <password> with the password you created for the admin user
  and <dbname> with the name of your database.
  • Ex: heroku config:set DB_URI="mongodb+srv://admin:yellowpencil@cluster0.pygcn.mongodb.net/atlas_db_test?retryWrites=true&w=majority"
  • NOTE: You don't have a database at this point yet, but MongoDB will
    create it as soon as you use your application to create data. So, in the
    example above, the atlas_db_test database will not exist until the first user
    is created via a sign-up.

Finish up the final deployment steps, then test your app to make sure it worked.

return to Deploying Heroku

Add AWS credentials

• Make sure you have generated your AWS secrets
  and have them in your local .env file. Things should work locally when interacting
  with AWS.
• Remember, your .env file contains secret credentials and should NOT be
  committed to git or pushed to GitHub. So, to deploy your app to another server,
  we have to manually set up the .env for that server, by hand.
• On Heroku, this is done via the heroku config:set command from the command line (or via the Heroku web dashboard):
  • heroku config:set SOME_KEY=some value, just like we did when we first deployed our express app

return to Deploying Heroku

WARNING: Ephemeral Filesystem

One serious limitation of Heroku is that it provides an 'ephemeral filesystem';
in other words, if you try to save a new file inside the repo (e.g. an uploaded
image file), it will disappear when your app is restarted or redeployed.

As an example, try running the following commands:

heroku run bash
touch happy.txt; echo 'is happy' > happy.txt
cat happy.txt

Then, hit Ctrl-D to get out of heroku bash shell. If you re-open the shell and
run ls -l, happy.txt will be missing!

The typical workaround is to save files in cloud storage such as Amazon
S3.

Troubleshooting

• First step upon encountering an issue should be to run heroku logs to
  read the logs of your deployed heroku server
• Heroku Addons
• Previous Issues
• If you are getting a CORS error and the CLIENT_ORIGIN is correct, ensure the
  DB_URI is set successfully with the value that MongoDB Atlas provides for your cluster.

Additional Resources

• Heroku Command Line

License

1. All content is licensed under a CC­BY­NC­SA 4.0 license.
2. All software code is licensed under GNU GPLv3. For commercial use or
   alternative licensing, please contact legal@ga.co.