Deploying Lambda Functions in One AWS Account and API Gateway in Another: A Serverless Solution

Discover how to deploy Lambda functions in one AWS account while creating API Gateway endpoints in another. Learn about the EventBridge approach as a seamless solution.
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Serverless Deployment Across Multiple AWS Accounts: A How-To Guide

When working with serverless applications, it's not uncommon to come across scenarios that require resources to be deployed across different AWS accounts. Imagine you have a serverless project that involves deploying AWS Lambda functions in one account, but you also need those functions accessible through an API Gateway that's set up in another AWS account. How do you achieve this kind of cross-account deployment? This post will dive into an effective solution using AWS EventBridge, avoiding the complexities that often accompany multi-account setups.

Understanding the Problem

You're faced with two main requirements:

Deploy Lambda Functions: You want to deploy your Lambda functions in one AWS account. This account will manage the backend logic and execution of your serverless functions.

Create API Gateway: Meanwhile, the API Gateway for accessing those functions needs to be set up in another AWS account. This is where challenges can arise due to the need for secure communication between accounts.

Typically, this type of setup could lead to the need for complex permissions, cross-account roles, or intricate ARN policies. However, there is a better way!

The EventBridge Solution: A Simplified Approach

AWS EventBridge provides a robust way to manage events between different AWS accounts. Here’s how you can leverage EventBridge to resolve the challenge of deploying Lambda functions and creating API Gateway endpoints across accounts without getting tangled in policy scripts or ARNs.

Step-by-Step Breakdown

Set Up EventBridge: First, ensure that you have the EventBridge service enabled in both AWS accounts. You will generally create an event bus in the account where the API Gateway resides.

Assign Permissions: You need to set up the necessary permissions so that the Lambda functions in your first account can send events to the EventBridge bus in the second account. This typically involves the following actions:

Create an IAM role in the API Gateway account that grants PutEvents permissions to the EventBridge.

Trust the Lambda function's account through the role, allowing it to write to EventBridge.

Modify Your Lambda Function: Below is a sample code snippet you would include in your Lambda function to publish events to EventBridge:

[[See Video to Reveal this Text or Code Snippet]]

Creating the API Gateway: With the Lambda function successfully sending events to the EventBridge, you can then set up the API Gateway in the second account to listen and handle the incoming events from the EventBridge.

Benefits of This Approach

Less Complexity: By using EventBridge, you can avoid the intricate details of dual-account ARNs and complicated permission policies.

Secure Communication: The interaction between your Lambda functions and API Gateway happens securely through event-driven architecture.

Seamless Integration: EventBridge naturally integrates with various AWS services, making it an excellent choice for building serverless architectures.

Conclusion

Deploying serverless functions in one AWS account while creating an API Gateway in another does not have to be a convoluted process. By following the EventBridge approach, you can efficiently manage events across accounts without the headache of complicated policies.

If you’re venturing into the AWS serverless ecosystem, consider leveraging the capabilities of EventBridge to simplify your deployment strategies. Happy coding!