Terraform AWS Lambda Function Deployment Example: A Step-by-Step Guide

In this tutorial, we will explore how to deploy AWS Lambda functions using Terraform. Terraform is a popular infrastructure as code (IaC) tool that allows you to manage and provision infrastructure resources, including AWS Lambda functions.

Prerequisites

Before you start, make sure you have the following prerequisites:

• AWS account with the necessary credentials set up
• Terraform installed on your machine
• A code editor or IDE of your choice

Step 1: Create a New Terraform Configuration File

Create a new file called main.tf and add the following code:

provider "aws" {
  region = "us-west-2"
}

resource "aws_lambda_function" "example" {
  filename      = "lambda_function_payload.zip"
  function_name = "example_lambda_function"
  handler       = "index.handler"
  runtime       = "nodejs14.x"
  role          = aws_iam_role.lambda_exec.arn
}

resource "aws_iam_role" "lambda_exec" {
  name        = "example_lambda_exec"
  description = "Execution role for example lambda function"

  assume_role_policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Action = "sts:AssumeRole"
        Effect = "Allow"
        Principal = {
          Service = "lambda.amazonaws.com"
        }
      }
    ]
  })
}

This code creates a new AWS Lambda function with the necessary execution role.

Step 2: Create a New Lambda Function Payload

Create a new file called index.js and add the following code:

exports.handler = async (event) => {
  console.log('Received event:', event)
  return {
    statusCode: 200,
    body: JSON.stringify('Hello from Lambda!'),
  };
};

This code creates a simple Lambda function that returns a Hello World message.

Step 3: Zip the Lambda Function Payload

Zip the index.js file into a new file called lambda_function_payload.zip.

Step 4: Initialize Terraform

Run the following command to initialize Terraform:

terraform init

Step 5: Apply the Terraform Configuration

Run the following command to apply the Terraform configuration:

terraform apply

This will create the AWS Lambda function and execution role in your AWS account.

Common Mistakes

Here are some common mistakes to watch out for:

• Make sure you have the correct AWS credentials set up
• Make sure you have the correct Terraform version installed
• Make sure you have the correct Lambda function payload zipped and uploaded

Conclusion

In this tutorial, we learned how to deploy an AWS Lambda function using Terraform. We created a new Terraform configuration file, created a new Lambda function payload, zipped the payload, initialized Terraform, and applied the Terraform configuration. We also covered some common mistakes to watch out for.