serverless.tf

locals {	
  function_name   = "hello_world"	
  handler         = "index.handler"
  runtime         = "nodejs14.x"
  zip_file        = "hello_world.zip"
}

data "archive_file" "zip" {	
  source_dir = "${path.module}/lambdas/hello-world"
  type = "zip"
  
  output_path = local.zip_file
}

resource "aws_lambda_function" "this" {
  description   = "${var.config.team}-lambda-stream-es"

  // Function parameters we defined at the beginning
  function_name = local.function_name
  handler = local.handler
  runtime = local.runtime	
  timeout = 15
  // Upload the .zip file Terraform created to AWS
  filename = local.zip_file
  source_code_hash = data.archive_file.zip.output_base64sha256

  // Connect our IAM resource to our lambda function in AWS
  role = var.config.es_lambda_role_arn
}

resource "aws_apigatewayv2_api" "this" {
  name          = "${var.config.team}-${var.config.env}-lambda-gw"
  protocol_type = "HTTP"
  
  cors_configuration {
    allow_origins = ["https://www.first.com", "https://www.second.com"]
    allow_methods = ["GET"]
    allow_headers = ["content-type"]
    max_age = 300
  }
}

resource "aws_apigatewayv2_stage" "this" {
  api_id = aws_apigatewayv2_api.this.id

  name          = "${var.config.team}-${var.config.env}-lambda-gw-stage"
  auto_deploy = true

  access_log_settings {
    destination_arn = aws_cloudwatch_log_group.this.arn

    format = jsonencode({
      requestId               = "$context.requestId"
      sourceIp                = "$context.identity.sourceIp"
      requestTime             = "$context.requestTime"
      protocol                = "$context.protocol"
      httpMethod              = "$context.httpMethod"
      resourcePath            = "$context.resourcePath"
      routeKey                = "$context.routeKey"
      status                  = "$context.status"
      responseLength          = "$context.responseLength"
      integrationErrorMessage = "$context.integrationErrorMessage"
      }
    )
  }
}

resource "aws_apigatewayv2_integration" "hello_world_integration" {
  api_id = aws_apigatewayv2_api.this.id

  integration_uri    = aws_lambda_function.this.invoke_arn
  integration_type   = "AWS_PROXY"
  integration_method = "POST"
}

resource "aws_apigatewayv2_route" "hello_world_route" {
  api_id = aws_apigatewayv2_api.this.id

  route_key = "GET /hello-world"
  target    = "integrations/${aws_apigatewayv2_integration.hello_world_integration.id}"
}

resource "aws_cloudwatch_log_group" "this" {
  name = "/aws/api_gw/${aws_apigatewayv2_api.this.name}"

  retention_in_days = 30
}

resource "aws_lambda_permission" "api_gw" {
  statement_id  = "AllowExecutionFromAPIGateway"
  action        = "lambda:InvokeFunction"
  function_name = aws_lambda_function.this.function_name
  principal     = "apigateway.amazonaws.com"

  source_arn = "${aws_apigatewayv2_api.this.execution_arn}/*/*"
}