Automating Stripe API Key Rotation with StripeConfig Operator

Question

Pulumi · Accepted Answer

To automate the rotation of Stripe API keys, you would typically need a secure mechanism to store the keys, a way to create new keys, a procedure to replace the old keys with new ones in your application, and ideally, an automated process that triggers rotation on a schedule or an event. However, as of my last update, Pulumi does not offer a direct integration with Stripe to manage API keys.

That said, you can still automate API key rotation using a combination of Pulumi and external scripts or serverless functions. To illustrate this, I'll describe an approach which involves using AWS Secrets Manager to store your Stripe API keys securely and a serverless Lambda function to perform the rotation. This isn't an entirely out-of-the-box solution with Pulumi, but Pulumi can set up the infrastructure.

Here's a conceptual overview of the process:

1. **Secrets Storage**: Store your API keys securely in AWS Secrets Manager.
2. **Rotation Function**: Write a serverless AWS Lambda function that interacts with the Stripe API to rotate the keys.
3. **Rotation Configuration**: Configure the Secrets Manager to use this lambda function to rotate the secret.

Let's walk through the Pulumi program to create such infrastructure.

```typescript
import * as aws from "@pulumi/aws";

// Step 1: Define the AWS Secret where the Stripe secret API key is stored.
const stripeApiSecret = new aws.secretsmanager.Secret("stripeApiSecret", {
    description: "Stripe API Secret Key",
    // The key rotation logic can be triggered automatically or manually
    rotationLambdaArn: null, // To be updated after creating the Lambda function
});

// Step 2: Create the AWS Lambda function that will rotate the Stripe API key.
// Note: The actual implementation of the rotation logic will have to be supplied.
const stripeKeyRotator = new aws.lambda.Function("stripeKeyRotator", {
    // Lambda function configuration
    runtime: aws.lambda.Runtime.NodeJS12dX,
    code: new pulumi.asset.AssetArchive({
        "index.js": new pulumi.asset.StringAsset(`
            // Lambda function code to rotate the Stripe API key
            // and update the AWS Secrets Manager secret value.
        `),
    }),
    handler: "index.handler",
    role: lambdaExecutionRole.arn, // Assume we have a role with the necessary permissions
    environment: {
        variables: {
            STRIPE_API_SECRET_ARN: stripeApiSecret.arn,
        },
    },
});

// Step 3: Define the secret rotation policy to specify how the Stripe API key should be rotated.
const stripeApiSecretRotation = new aws.secretsmanager.SecretRotation("stripeApiSecretRotation", {
    secretId: stripeApiSecret.id,
    rotationLambdaArn: stripeKeyRotator.arn,
    rotationRules: {
        automaticallyAfterDays: 30, // Automatically rotate every 30 days
    },
});

// Set the Lambda function as the rotation function for the secret (circular reference handled by Pulumi automatically).
stripeApiSecret.rotationLambdaArn = stripeKeyRotator.arn;

// Export the secret ARN for the rotated Stripe API key
export const stripeApiSecretArn = stripeApiSecret.arn;
```

In this code:

- We define an AWS Secret to store the Stripe API key securely.
- We allocate a stubbed AWS Lambda function, which you will populate with code to rotate the Stripe key (using Node.js in this illustration). The Lambda function will require access to the Stripe API and to AWS Secrets Manager to replace the old key with a new one. You'll need to put your Stripe key rotation logic into the Asset pointed to by `"index.js"`.
- We create a SecretRotation resource that defines rotation policies for our stored API keys, with the Lambda function serving as the rotation function.
  
The actual Lambda function will need the proper logic to use Stripe's API for key rotation and handling the storage mechanics in AWS Secrets Manager. You would use the Stripe Node.js library and AWS SDK within the Lambda function to accomplish this.

For detailed instructions on how to write the rotation logic within a Lambda function and interact with the Stripe API, you would need to consult the Stripe API documentation and the AWS Secrets Manager documentation. Keep in mind that specifics of key rotation strategies and best practices for security are beyond the scope of this walk-through.

Remember that rotating secret keys can potentially disrupt your service if not done properly, as any ongoing Stripe transactions might fail if they're using a now-deprecated key. Ensure that your application's error handling and retry mechanisms are robust to handle such cases smoothly.