Terraform config for basic lambda and api gateway integration

aws-lambda-api-gateway.tf

provider "aws" {
    region = "eu-west-1"
    profile = "my-profile"
}

resource "aws_iam_role" "iam_for_lambda" {
  name = "iam_for_lambda"

  assume_role_policy = <<EOF
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Action": "sts:AssumeRole",
      "Principal": {
        "Service": "lambda.amazonaws.com"
      },
      "Effect": "Allow",
      "Sid": ""
    }
  ]
}
EOF
}

resource "aws_lambda_function" "test_lambda" {
  filename      = "function.zip"
  function_name = "lambda_example_terraform"
  role          = "${aws_iam_role.iam_for_lambda.arn}"
  handler       = "index.handler"

  # The filebase64sha256() function is available in Terraform 0.11.12 and later
  # For Terraform 0.11.11 and earlier, use the base64sha256() function and the file() function:
  # source_code_hash = "${base64sha256(file("lambda_function_payload.zip"))}"
  source_code_hash = "${filebase64sha256("function.zip")}"

  runtime = "nodejs8.10"
}

resource "aws_lambda_permission" "handler_apigateway_permission" {
  function_name = "${aws_lambda_function.test_lambda.arn}"
  action = "lambda:InvokeFunction"
  statement_id = "AllowExecutionFromApiGateway"
  principal = "apigateway.amazonaws.com"
}

resource "aws_api_gateway_rest_api" "rest_api" {
  name        = "ServerlessExample"
  description = "Terraform Serverless Application Example"
  body = "${templatefile("${path.module}/openapi.yml", {
    execution_arn = "${aws_lambda_function.test_lambda.invoke_arn}"
  })}"

  depends_on = ["aws_lambda_function.test_lambda"]
}


resource "aws_api_gateway_deployment" "stage" {
  rest_api_id = "${aws_api_gateway_rest_api.rest_api.id}"
  stage_name  = "testing"
}