Transactional Email Notifications via Auth0 for Applications

Question

Pulumi · Accepted Answer

Transactional email notifications are crucial for applications to communicate with users for various scenarios, such as account verification, password resets, alerts, and other notifications. Integrating Auth0 with your application can help manage, authenticate, and send emails to the users.

In the context of implementing this with Pulumi, the main resources we will be dealing with are:

- **Auth0 User**: Represents a user in Auth0.
- **Auth0 Email**: Configures email providers and settings in Auth0.
- **Auth0 Hook**: Hooks are functions that get executed in response to specific trigger events in Auth0. We can use hooks for sending transactional emails after specific events such as user registration.
- **Auth0 Action**: Actions represent reusable pieces of logic that execute flows, such as sending an email upon successful user sign-up.

Below is a Pulumi Python program that demonstrates how to set up Auth0 users and configure an email provider for transactional emails via hooks or actions (we'll be using hooks in this example). This will allow the application to send emails to the users after certain events, like user registration.

```python
import pulumi
import pulumi_auth0 as auth0

# Example of creating an Auth0 user that might receive transactional emails
auth0_user = auth0.User("example-user",
    connection_name="Username-Password-Authentication", # Typically the default DB connection in Auth0
    email="user@example.com",
    password="A very strong password 123!", # Always encourage using a strong, secure password
    email_verified=True, # This is set to true for the sample, but in a real scenario it might be false initially until the user verifies their email
    app_metadata={
        # App metadata can store information that does not change in user interactions
        "roles": ["subscriber"], # Example role
    },
    user_metadata={
        # User metadata can store user attributes like preferences
        "theme": "dark",
    },
)

# Example of setting up an email service that Auth0 can use for transactional emails
auth0_email = auth0.Email("example-email",
    name="example-email-provider",
    credentials={
        "smtp_host": "smtp.example.com",
        "smtp_port": 587,
        "smtp_user": "smtp-user",
        "smtp_pass": "smtp-password",
    },
    default_from_address="no-reply@example.com",
)

# Example of a hook that sends an email after a new user registration
auth0_hook = auth0.Hook("send-email-on-registration",
    script="""module.exports = function (user, context, cb) {
        // This is a Node.js code that will be run by Auth0 after a new user registration
        // Replace it with your email sending logic and customize it as per your needs.
        const userEmail = user.email;
        const sendEmail = (email) => {
            // Logic to send the email
            console.log(`Send welcome email to ${email}`);
            // ... add more code to handle email sending
        };
        sendEmail(userEmail);
        cb(); // Do not forget to call the callback at the end!
    };""",
    trigger_id="post-user-registration", # Specifies the trigger event that Auth0 will use to execute this hook
    enabled=True,
)

# Export some of the resource attributes for external usage or reference
# (e.g., in a CI/CD pipeline, or when referencing the user's information elsewhere)
pulumi.export('auth0_user_id', auth0_user.user_id)
pulumi.export('auth0_email_name', auth0_email.name)
pulumi.export('auth0_hook_id', auth0_hook.id)
```

In this program:

- An `Auth0 User` is created with an email address, password, and metadata. This represents a user in your Auth0 system. Metadata is used to store information about the users, such as their roles and preferences.

- An `Auth0 Email` service is configured to use an SMTP provider with host details, and a default "from" address is set.

- An `Auth0 Hook` is put in place, triggered by `post-user-registration`. When a new user registers to your application, the hook will execute Node.js code (you can adapt this to your email sending logic). The provided script is a placeholder where you can add your email sending functionality using your SMTP server or an email API.

Remember, after you've written and applied your Pulumi configuration, you would need to configure the email service provider with proper authentication credentials, which might differ based on your email service provider.

By exporting ids and names of the resources, we can retrieve their identifiers when we run `pulumi up`, which is handy if we need to reference these resources outside of our Pulumi program. For example, you might need the user ID to make updates to the user in a separate administrative script or the hook ID to debug why an email might not have been sent after registration.

The script used in the `auth0_hook` is a simple console log in JavaScript that simulates sending an email. In a real implementation, you would replace this with actual email sending logic, possibly using a third-party library or API that interfaces with your selected email service provider.