Nhost CLI: From Zero to Production

In the previous tutorials, that are covered in the documentation, we tested various parts of Nhost, such as:

Database
GraphQL API
Permission
JavaScript SDK
Authentication

All changes we did to our database and API happened directly in the production of our Nhost app.

It’s not ideal for making changes in production because you might break things, which will affect all users of your app.

Instead, it’s recommended to make changes and test your app locally before deploying those changes to production.

To do changes locally, we need to have a complete Nhost app running locally, which the Nhost CLI does.

The Nhost CLI matches your production application in a local environment, this way you can make changes and test your code before deploying your changes to production.

Recommended workflow with Nhost

Develop locally using the Nhost CLI.
Push changes to GitHub.
Nhost automatically applies changes to production.

What you’ll learn in this guide:

Use the Nhost CLI to create a local environment
Connect a GitHub repository with a Nhost app
Deploy local changes to production

Setup the recommended workflow with Nhost

What follows is a detailed tutorial on how you setup Nhost for this workflow

Create Nhost App

Create a new Nhost app for this tutorial.

It’s important that you create a new Nhost app for this guide instead of reusing an old Nhost app because we want to start with a clean Nhost app.

Create new GitHub Repository

Create a new GitHub repository for your new Nhost app. The repo can be both private or public.

Connect GitHub Repository to Nhost App

In the Nhost Console, go to the dashboard of your Nhost app and click Connect to GitHub.

Install the Nhost CLI

Install the Nhost CLI using the following command:



sudo curl -L https://raw.githubusercontent.com/nhost/cli/main/get.sh | bash

Initialize a new Nhost App locally:



nhost init -n "nhost-example-app" && cd nhost-example-app

And initialize the GitHub repository in the same folder:



echo "# nhost-example-app" >> README.md
git init
git add README.md
git commit -m "first commit"
git branch -M main
git remote add origin https://github.com/[github-username]/nhost-example-app.git
git push -u origin main

Now go back to the Nhost Console and click Deployments. You just made a new deployment to your Nhost app!

If you click on the deployment you can see that nothing was really deployed. That’s because we just made a change to the README file.

Let’s do some backend changes!

Local changes

Start Nhost locally:



nhost dev

💡 Make sure you have Docker installed on your computer. It’s required for Nhost to work.

The nhost dev command will automatically start a complete Nhost environment locally on your computer using:

Postgres
Hasura
Authentication
Storage
Serverless Functions
Mailhog

You use this local environment to do changes and testing before you deploy your changes to production.

Running nhost dev also starts the Hasura Console.

💡 It’s important that you use the Hasura Console that is started automatically when you do changes. This way, changes are automatically tracked for you.

In the Hasura Console, create a new table customers with two columns:

id
name

When we created the customers table there was also a migration created automatically. The migration was created at under nhost/migrations/default.



$ ls -la nhost/migrations/default
total 0
drwxr-xr-x  3 eli  staff   96 Feb  7 16:19 .
drwxr-xr-x  3 eli  staff   96 Feb  7 16:19 ..
drwxr-xr-x  4 eli  staff  128 Feb  7 16:19 1644247179684_create_table_public_customers

This database migration has only been applied locally, meaning, you created the customers table locally but it does not (yet) exists in production.

To apply the local change to production we need to commit the changes and push it to GitHub. Nhost will then automatically pick up the change in the repository and apply the changes.

💡 You can commit and push files in another terminal while still having nhost dev running.



git add -A
git commit -m "Initialized Nhost and added a customers table"
git push

Head over to the Deployments tab in the Nhost console to see the deployment.

Once the deployment finishes the customers table is created in production.

We’ve now completed the recommended workflow with Nhost:

Develop locally using the Nhost CLI.
Push changes to GitHub.
Nhost deploys changes to production.

Apply metadata and Serverless Functions

In the previous section, we only created a new table; customers. Using the CLI you can also do changes to other parts of your backend.

There are three things the CLI and the GitHub integration track and applies to production:

Database migrations
Hasura Metadata
Serverless Functions

For this section, let’s do one change to the Hasura metadata and create one serverless function

Hasura Metadata

We’ll add permissions to the users table, making sure users can only see their own data. For this, go to the auth schema and click on the users table. then click on Permissions and enter a new role user and create a new select permission for that role*.*

Create the permission with custom check:



{
  "id": {
    "_eq" : "X-Hasura-User-Id"
  }
}

Select the following columns:

id
created_at
display_name
avatar_url
email

Then click Save permissions.

Now, let’s do a git status again to confirm the permission changes we did were tracked locally in your git repository.

We can now commit this change:



git add -A
git commit -m "added permission for uses"

Now let’s create a serverless function before we push all changes to GitHub so Nhost can deploy our changes.

Serverless Function

A serverless function is a piece of code written in JavaScript or TypeScript that takes an HTTP request and returns a response.

Here’s an example:



import { Request, Response } from 'express'

export default (req: Request, res: Response) => {
  res.status(200).send(`Hello ${req.query.name}!`)
}

Serverless functions are placed in the functions/ folder of your repository. Every file will become its own endpoint.

Before we create our serverless function we’ll install express, which is a requirement for serverless functions to work.



npm install express
# or with yarn
yarn add express

We’ll use TypeScript so we’ll install two type definitions too:



npm install -d @types/node @types/express
# or with yarn
yarn add -D @types/node @types/express

Then we’ll create a file functions/time.ts

In the file time.ts we’ll add the following code to create our serverless function:



import { Request, Response } from 'express';

export default (req: Request, res: Response) => {
  return res
    .status(200)
    .send(`Hello ${req.query.name}! It's now: ${new Date().toUTCString()}`);
};

We can now test the function locally. Locally, the backend URL is http://localhost:1337. Functions are under /v1/functions. And every function’s path and filename becomes an API endpoint.

This means our function functions/time.ts is at http://localhost:1337/v1/functions/time.

Let’s use curl to test our new function:



curl http://localhost:1337/v1/functions/time
Hello undefined! It's now: Sun, 06 Feb 2022 17:44:45 GMT

And with a query parameter with our name:



curl http://localhost:1337/v1/functions/time\?name\=Johan
Hello Johan! It's now: Sun, 06 Feb 2022 17:44:48 GMT

Again, let’s use git status to see the changes we did to create our serverless function.

Now let’s commit the changes and push them to GitHub.



git add -A
git commit -m "added serverless function"
git push

In the Nhost Console, click on the new deployment to see details

After Nhost has finished deploying your changes we can test them in production. First let’s confirm that the user permissions are applied.

Then, let’s confirm that the serverless function was deployed. Again, we’ll use curl:



curl https://your-backend-url.nhost.run/v1/functions/time\?name\=Johan

Conclusion

In this tutorial, we have installed the Nhost CLI and created a local Nhost environment to do local development and testing.

In the local environment, we’ve made changes to our database, to Hasura’s metadata, and created a serverless function.

We’ve connected a GitHub repository and pushed our changes to GitHub.

We’ve seen Nhost automatically deploying our changes and we’ve verified that the changes were applied.

In summary, we’ve set up a productive environment using the recommended Nhost workflow:

Develop locally using the Nhost CLI.
Push changes to GitHub.
Nhost deploys changes to production.

In addition to all that, the Nhost team is always happy to support you with any questions you might have on Discord and Github!

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