In Terraform, how do you specify an API Gateway endpoint with a variable in the request path?

Question

In AWS API Gateway, I have a endpoint defined as /users/{userId}/someAction, and I'm trying to recreate this with terraform

I would start having some sort of linked gateway_resource chain like so...

resource "aws_api_gateway_resource" "Users" {
  rest_api_id = "${var.rest_api_id}" 
  parent_id = "${var.parent_id}" 
  path_part = "users"
}

//{userId} here?

resource "aws_api_gateway_resource" "SomeAction" {
  rest_api_id = "${var.rest_api_id}" 
  parent_id = "${aws_api_gateway_resource.UserIdReference.id}"
  path_part = "someAction"
}

In which I then define the aws_api_gateway_method and everything else.

How do I define this endpoint in terraform? The terraform documentation and examples don't cover this use case.

Answer 1

You need to define a resource whose path_part is the parameter you want to use:

// List
resource "aws_api_gateway_resource" "accounts" {
    rest_api_id = var.gateway_id
    parent_id   = aws_api_gateway_resource.finance.id
    path_part   = "accounts"
}

// Unit
resource "aws_api_gateway_resource" "account" {
  rest_api_id = var.gateway_id
  parent_id   = aws_api_gateway_resource.accounts.id
  path_part   = "{accountId}"
}

Then you create the method and enable the path parameter:

resource "aws_api_gateway_method" "get-account" {
  rest_api_id   = var.gateway_id
  resource_id   = var.resource_id
  http_method   = "GET"
  authorization = "NONE"

  request_parameters = {
    "method.request.path.accountId" = true
  }
}

And finally you can successfully create the mapping within the integration:

resource "aws_api_gateway_integration" "get-account-integration" {
    rest_api_id             = var.gateway_id
    resource_id             = var.resource_id
    http_method             = aws_api_gateway_method.get-account.http_method
    type                    = "HTTP"
    integration_http_method = "GET"
    uri                     = "/integration/accounts/{id}"
    passthrough_behavior    = "WHEN_NO_MATCH"

    request_parameters = {
        "integration.request.path.id" = "method.request.path.accountId"
    }
}

The method needs to be there - and with the parameter enabled - in order for the integration mapping to work.