Building a Serverless Application Repository with Terraform

Introduction :-

In the ever-evolving world of #CloudComputing, #serverless #architecture is becoming increasingly popular. One of the key aspects of this architecture is the ability to create, #deploy, and manage applications without worrying about infrastructure. To take full advantage of serverless technology, you need a structured and efficient way to manage your serverless applications. This is where #Terraform, the #infrastructure-as-code tool, comes into play.

Prerequisites :

• AWS account

• #AWS CLI installed and configured

• #Terraform installed

Step-1 : AWS CLI Configuration

1.1. Ensure that you have the AWS CLI installed on your local machine.

1.2. Configure your AWS CLI with the necessary AWS credentials.

aws configure

Step-2 : Terraform Installation and Configuration

2.1. Install #Terraform on your local machine.

2.2. Verify the #Terraform installation.

terraform version

Step-3 : Creating the Terraform Project Structure

3.1. Create a new directory for your #Terraform project.

3.2. Organize your project directory with the following structure:

serverless-app-repo/
│ main.tf
│ lambda_function.zip
│ requirements.txt
│ lambda_function.py

• main.tf: The main configuration file for defining AWS resources.

• lambda_function.zip: The Lambda #deployment package.

• requirements.txt: Dependencies for your Lambda function.

• lambda_function.py: The #Python code for your Lambda function.

main.tf-

provider "aws" {
  region = "eu-central-1" # Update to match your AWS CLI profile region
  profile = "default"
 }
# Create an S3 bucket for storing application artifacts
resource "aws_s3_bucket" "app_repository" {
  bucket = "serverless-app-repository" # Update the bucket name as needed
}
# Define IAM roles and policies
resource "aws_iam_role" "lambda_role" {
  name = "lambda_execution_role"
  assume_role_policy = jsonencode({
  Version = "2012–10–17",
   Statement = [
   {
      Action = "sts:AssumeRole",
      Effect = "Allow",
       Principal = {
       Service = "lambda.amazonaws.com"
      }
     }
    ]
  })
}
# Define IAM policy for Lambda function
resource "aws_iam_policy" "lambda_policy" {
  name = "lambda_policy"
  description = "Policy for Lambda functions in the repository"
  # Define your policy document here
  policy = jsonencode({
   Version = "2012–10–17",
    Statement = [
     {
      Action = [  
          "lambda:InvokeFunction",
      # Add other actions as needed
      ],
      Effect = "Allow",
      Resource = "*",
      },
    ],
  })
}
# Attach managed policies to the Lambda execution role
resource "aws_iam_policy_attachment" "lambda_role_policy_attachment" {
  name = "lambda-policy-attachment"
  policy_arn = aws_iam_policy.lambda_policy.arn
  roles = [aws_iam_role.lambda_role.name]
}
# Attach AWSLambdaBasicExecutionRole managed policy
resource "aws_iam_policy_attachment" "lambda_basic_execution_attachment" {
  name = "lambda-basic-execution-policy-attachment"
  policy_arn = "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
  roles = [aws_iam_role.lambda_role.name]
}
# Define IAM policy for CloudWatch Logs
resource "aws_iam_policy" "cloudwatch_logs_policy" {
  name = "cloudwatch_logs_policy"
  description = "Policy for CloudWatch Logs access"
  policy = jsonencode({
   Version = "2012–10–17",
    Statement = [
    {
     Action = [
       "logs:CreateLogGroup",
       "logs:CreateLogStream",
       "logs:PutLogEvents",
       "logs:DescribeLogStreams",
      ],
     Effect = "Allow",
     Resource = "*",
    },
    ],
  })
}
# Attach CloudWatch Logs policy to the Lambda execution role
resource "aws_iam_policy_attachment" "cloudwatch_logs_attachment" {
  name = "cloudwatch-logs-policy-attachment"
  policy_arn = aws_iam_policy.cloudwatch_logs_policy.arn
  roles = [aws_iam_role.lambda_role.name]
}
# Define IAM policy for S3 full access
resource "aws_iam_policy" "s3_full_access_policy" {
  name = "s3-full-access-policy"
  description = "Policy for S3 full access"
  policy = jsonencode({
   Version = "2012–10–17",
   Statement = [
    {
     Action = [
            "s3:*",
       ],
     Effect = "Allow",
     Resource = "*",
    },
    ],
  })
 }
# Attach S3 full access policy to the Lambda execution role
resource "aws_iam_policy_attachment" "s3_full_access_attachment" {
  name = "s3-full-access-policy-attachment"
  policy_arn = aws_iam_policy.s3_full_access_policy.arn
  roles = [aws_iam_role.lambda_role.name]
}
# Define AWS Lambda function
resource "aws_lambda_function" "list_applications" {
  filename = "list_applications.zip" # Specify the correct path to your deployment package
  function_name = "newFunctionName" # Update with your desired function name
  role = aws_iam_role.lambda_role.arn
  handler = "list_applications.list_applications" # Specify the correct Python module and function name
  runtime = "python3.8" # Use the correct Python runtime version
  source_code_hash = filebase64sha256("list_applications.zip") # Ensure the package exists
}
# Create an AWS API Gateway for your repository
resource "aws_api_gateway_rest_api" "repository_api" {  
  name = "repository_api"
  description = "Serverless Application Repository API"
}

resource "aws_api_gateway_resource" "repository_resource" {
  rest_api_id = aws_api_gateway_rest_api.repository_api.id
  parent_id = aws_api_gateway_rest_api.repository_api.root_resource_id
  path_part = "v1"
}

Step-4 : Running Terraform

4.1. Initialize your #Terraform project.

terraform init

4.2. Review the execution plan to ensure there are no errors.

terraform plan

4.3. Apply the Terraform configuration to create AWS resources.

terraform apply

Step-5 : Testing the Serverless Application

5.1. Verify that all AWS resources have been created successfully.

5.2. Test your #serverless application by invoking the Lambda function.

Step-6 : Viewing Logs

6.1. Access #CloudWatch Logs to view and #troubleshoot logs generated by your Lambda function.

Conclusion :-

Building a #Serverless Application #Repository with #Terraform is more than just a technical exercise; it’s a strategic move to enhance your #organization efficiency and agility. With #Terraform’s power to codify your #infrastructure, you can create a centralized repository for your serverless applications. This not only simplifies the #deployment process but also ensures #consistency and reliability.