API Gateway/Lambda Example

api_gateway.tf

resource "aws_api_gateway_rest_api" "example" {
  name        = "ServerlessExample"
  description = "Terraform Serverless Application Example"
}

resource "aws_api_gateway_resource" "proxy" {
  rest_api_id = "${aws_api_gateway_rest_api.example.id}"
  parent_id   = "${aws_api_gateway_rest_api.example.root_resource_id}"
  path_part   = "{proxy+}"
}

resource "aws_api_gateway_method" "proxy" {
  rest_api_id   = "${aws_api_gateway_rest_api.example.id}"
  resource_id   = "${aws_api_gateway_resource.proxy.id}"
  http_method   = "ANY"
  authorization = "NONE"
}

resource "aws_api_gateway_integration" "lambda" {
  rest_api_id = "${aws_api_gateway_rest_api.example.id}"
  resource_id = "${aws_api_gateway_method.proxy.resource_id}"
  http_method = "${aws_api_gateway_method.proxy.http_method}"

  integration_http_method = "POST"
  type                    = "AWS_PROXY"
  uri                     = "${aws_lambda_function.example.invoke_arn}"
}

resource "aws_api_gateway_method" "proxy_root" {
  rest_api_id   = "${aws_api_gateway_rest_api.example.id}"
  resource_id   = "${aws_api_gateway_rest_api.example.root_resource_id}"
  http_method   = "ANY"
  authorization = "NONE"
}

resource "aws_api_gateway_integration" "lambda_root" {
  rest_api_id = "${aws_api_gateway_rest_api.example.id}"
  resource_id = "${aws_api_gateway_method.proxy_root.resource_id}"
  http_method = "${aws_api_gateway_method.proxy_root.http_method}"

  integration_http_method = "POST"
  type                    = "AWS_PROXY"
  uri                     = "${aws_lambda_function.example.invoke_arn}"
}

resource "aws_api_gateway_deployment" "example" {
  depends_on = [
    "aws_api_gateway_integration.lambda",
    "aws_api_gateway_integration.lambda_root",
  ]

  rest_api_id = "${aws_api_gateway_rest_api.example.id}"
  stage_name  = "test"
}

output "base_url" {
  value = "${aws_api_gateway_deployment.example.invoke_url}"
}

lambda.tf

provider "aws" {
  region = "us-east-1"
}

variable "app_version" {
}

resource "aws_lambda_function" "example" {
  function_name = "ServerlessExample"

  # The bucket name as created earlier with "aws s3api create-bucket"
  s3_bucket = "analyzere-terraform-serverless-example"
  s3_key    = "v${var.app_version}/example.zip"

  # "main" is the filename within the zip file (main.js) and "handler"
  # is the name of the property under which the handler function was
  # exported in that file.
  handler = "main.handler"
  runtime = "nodejs6.10"

  role = "${aws_iam_role.lambda_exec.arn}"
}

# IAM role which dictates what other AWS services the Lambda function
# may access.
resource "aws_iam_role" "lambda_exec" {
  name = "serverless_example_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_permission" "apigw" {
  statement_id  = "AllowAPIGatewayInvoke"
  action        = "lambda:InvokeFunction"
  function_name = "${aws_lambda_function.example.arn}"
  principal     = "apigateway.amazonaws.com"

  # The /*/* portion grants access from any method on any resource
  # within the API Gateway "REST API".
  source_arn = "${aws_api_gateway_deployment.example.execution_arn}/*/*"
}

main.js

'use strict'

exports.handler = function(event, context, callback) {
  var response = {
    statusCode: 200,
    headers: {
      'Content-Type': 'text/html; charset=utf-8'
    },
    body: '<p>Bonjour au monde!</p>'
  }
  callback(null, response)
}