Model/deployment/lambda/whlg_calculator/whlg_lambda.tf

# Reference existing IAM role
data "aws_iam_role" "lambda_exec_role" {
  name = "lambda-exec-role"
}

# Reference existing ECR repository
data "aws_ecr_repository" "whlg_calc_adhoc_ecr" {
  name = "whlg_calc_adhoc_ecr"
}

# SQS queue
resource "aws_sqs_queue" "whlg_calc_adhoc_queue" {
  name = "whlg_calc_adhoc-queue"
  visibility_timeout_seconds  = 1800  # 30 minutes (>= 300s and ~6x Lambda timeout)
}


# Custom IAM policy specific to lambda_example
resource "aws_iam_policy" "whlg_calc_adhoc_policy" {
  name = "walthamforest_adhoc_policy_lambda"

  policy = jsonencode({
    Version = "2012-10-17",
    Statement = [
      {
        Effect = "Allow",
        Action = [
          "sqs:ReceiveMessage",
          "sqs:DeleteMessage",
          "sqs:GetQueueAttributes",
          "sqs:GetQueueUrl",
          "sqs:ChangeMessageVisibility"
        ],
        Resource = aws_sqs_queue.whlg_calc_adhoc_queue.arn
      },
      {
        Effect = "Allow",
        Action = [
          "ecr:GetDownloadUrlForLayer",
          "ecr:BatchGetImage",
          "ecr:BatchCheckLayerAvailability"
        ],
        Resource = data.aws_ecr_repository.whlg_calc_adhoc_ecr.arn
      },
      {
        Effect = "Allow",
        Action = ["ecr:GetAuthorizationToken"],
        Resource = "*"
      }
    ]
  })
}

resource "aws_iam_role_policy_attachment" "whlg_calc_adhoc_policy_attach" {
  role       = data.aws_iam_role.lambda_exec_role.name
  policy_arn = aws_iam_policy.whlg_calc_adhoc_policy.arn
}

# Lambda function
resource "aws_lambda_function" "whlg_calc_adhoc" {
  function_name = "whlg_calc_adhoc"
  role          = data.aws_iam_role.lambda_exec_role.arn
  package_type  = "Image"
  image_uri     = "${data.aws_ecr_repository.whlg_calc_adhoc_ecr.repository_url}:${var.lambda_image_tag}"
  # Increase timeout (max 900 sec / 15 min)
  # timeout       = 300   # e.g. 5 minutes

  # Increase memory (default 128 MB)
  memory_size   = 2048  # try 1024 or 2048 MB to start

  # environment {
  #   variables = {
  #     DATABASE_URL = "postgresql://postgres:makingwarmhomes@terraform-20250331175522503500000002.cdgzupxvdyp0.eu-west-2.rds.amazonaws.com:5432/surveyDB"
  #   }
  # }
}

# SQS trigger
resource "aws_lambda_event_source_mapping" "whlg_calc_adhoc_trigger" {
  event_source_arn = aws_sqs_queue.whlg_calc_adhoc_queue.arn
  function_name    = aws_lambda_function.whlg_calc_adhoc.arn
  batch_size       = 1
}