What is the procedure for using Mailgun with Google Compute Engine in TypeScript

Question

Pulumi · Accepted Answer

To integrate Mailgun with Google Compute Engine using Pulumi in TypeScript, you would typically follow several steps:

1. Set up a Google Compute Engine instance that will run your application.
2. Install necessary software and configure the instance to send emails through Mailgun.
3. Use environment variables or instance metadata to store your Mailgun API credentials securely.

Below, you'll find a program written in TypeScript, utilizing Pulumi to configure and deploy a Google Compute Engine instance. This instance can be used to interact with Mailgun's API for sending emails. Please note that actual Mailgun integration in your application code (e.g., Node.js scripts, etc.) is beyond the scope of this Pulumi program.

For this guide, we are assuming:

- You have Pulumi CLI and Google Cloud SDK installed and configured for the desired project and zone.
- You are familiar with Google Compute Engine and Mailgun, and you have an account and API credentials from Mailgun.
- You have a basic understanding of TypeScript and Node.js for when you need to configure your application to use Mailgun APIs.

Let's begin by writing the Pulumi program to set up the Google Compute Engine instance. We will use the `gcp.compute.Instance` resource, which is an abstraction over Google Compute Engine VMs:

```typescript
import * as pulumi from '@pulumi/pulumi';
import * as gcp from '@pulumi/gcp';

const computeInstanceName = "mailgun-instance";

// Create a new Google Compute Engine instance
const instance = new gcp.compute.Instance(computeInstanceName, {
    // General configuration for the instance
    name: computeInstanceName,
    machineType: "f1-micro", // You should choose the type based on your needs
    zone: "us-central1-a", // Change the zone based on your preference

// The boot disk configuration
    bootDisk: {
        initializeParams: {
            image: "debian-cloud/debian-9", // You can change the image as required
        },
    },

// Configuration for network interfaces
    networkInterfaces: [{
        network: "default", // Using the default VPC network
        accessConfigs: [{}], // This line assigns an external IP. Remove if not needed
    }],

// You can set tags and labels depending on your organizational needs
    tags: ["mailgun"], // Tags help organize and control access with firewall rules
    labels: {"usage": "mailgun-email"},

// Metadata can be used to pass your Mailgun configuration securely
    metadata: {
        "MAILGUN_DOMAIN": "your.mailgun.domain", // Replace with your Mailgun domain
        "MAILGUN_API_KEY": "your_mailgun_api_key", // Replace with your Mailgun API key
        // The metadata_startup_script is used to prepare your instance after boot
        "startup-script": `#!/bin/bash
        # Your startup commands here
        # For example, install software, download your application code, etc.
        # Install mail software and dependencies (this is just an example)
        sudo apt-get update
        sudo apt-get install -y postfix mailutils
        `,
    },
});

// Export the instance's external IP address
export const instanceExternalIp = instance.networkInterfaces.apply(ni => ni[0].accessConfigs![0].natIp);
```

This program sets up a new Google Compute Engine instance with the relevant configuration to run your application and gives it access to your Mailgun credentials through metadata. The metadata startup script is a placeholder for whatever setup you need to do on your server. Replace the section with the appropriate commands to install software and configuration for your use case.

Remember to replace `your.mailgun.domain` and `your_mailgun_api_key` with your actual Mailgun details. Also, it's good practice to use a secrets manager rather than plaintext metadata for sensitive information like API keys in production.

After your instance is configured and running, your application should use the Mailgun API according to Mailgun's documentation to send emails. That part of code would be in whatever application or script you are running on the Compute Engine instance, which is not covered in this Pulumi program.

Please note that this is a basic setup, and for production use, you would need to consider a wide range of other factors including security groups, IAM roles, monitoring, and logging among others.