elgrove / terroir

An AWS pattern for very fast serverless app development

Terroir

An AWS pattern for super fast app development, combining the speed of AWS Chalice and the full array of AWS resources that can be declared in Terraform.

How it works

Write application code in Python, using a Chalice decorator to create a Lambda and all of the resources it requires, including API Gateway and IAM roles

@app.route("/item/{id}", methods=["GET"])
def get_item(id):
    """API Endpoint back by a Lambda, returns a DynamoDB table item."""
    table = boto3.resource("dynamodb").Table(os.environ["TABLE_NAME"])
    response = table.get_item(Key={"id": id})
    if item := response.get("Item"):
        return json.dumps(item)
    else:
        raise NotFoundError

Write additional resources that Chalice does not manage in Terraform (in this example, a DynamoDB table)

resource "aws_dynamodb_table" "dynamo-table" {
  name           = "dynamo-table"
  billing_mode   = "PROVISIONED"
  read_capacity  = 5
  write_capacity = 5
  hash_key       = "id"

  attribute {
    name = "id"
    type = "S"
  }

}

At build and deploy time, Chalice generates the Terraform for the resources it manages

chalice package --pkg-format terraform ../infra/

Terraform can then deploy all resources, generated with Chalice or written in Hcl, to AWS with a single command

make deploy