Using terraform modules for multiple regional api gateway - amazon-web-services

Question

I am using terraform to create aws infrastructure with 4 regional api gateways with corresponding dynamodb in that region.
I want to create one module consisting of ( API + dynamo ) with configurable region specific values. Is it possible with terraform? Or I would have to create 4 separate API + 4 separate dynamodb resources.
Any links or documentation would be helpful as well.
Currently working for regional API gateway and corresponding dynamodb.
variable "access_key" {}
variable "secret_key" {}
provider "aws" {
access_key = "${var.access_key}"
secret_key = "${var.secret_key}"
alias = "us-east-1"
region = "us-east-1"
}
provider "aws" {
access_key = "${var.access_key}"
secret_key = "${var.secret_key}"
alias = "us-west-2"
region = "us-west-2"
}
resource "aws_dynamodb_table" "us-east-1" {
provider = "aws.us-east-1"
hash_key = "test_tf"
name = "test_tf"
stream_enabled = true
stream_view_type = "NEW_AND_OLD_IMAGES"
read_capacity = 1
write_capacity = 1
attribute {
name = "test_tf"
type = "S"
}
}
resource "aws_dynamodb_table" "us-west-2" {
provider = "aws.us-west-2"
hash_key = "test_tf"
name = "test_tf"
stream_enabled = true
stream_view_type = "NEW_AND_OLD_IMAGES"
read_capacity = 1
write_capacity = 1
attribute {
name = "test_tf"
type = "S"
}
}
resource "aws_dynamodb_global_table" "test_tf" {
depends_on = ["aws_dynamodb_table.us-east-1", "aws_dynamodb_table.us-west-2"]
provider = "aws.us-east-1"
name = "test_tf"
replica {
region_name = "us-east-1"
}
replica {
region_name = "us-west-2"
}
}
resource "aws_api_gateway_rest_api" "test-us-east-1" {
name = "test-us-east-1"
endpoint_configuration {
types = ["REGIONAL"]
}
}
resource "aws_api_gateway_resource" "sample_test" {
rest_api_id = "${aws_api_gateway_rest_api.test-us-east-1.id}"
parent_id = "${aws_api_gateway_rest_api.test-us-east-1.root_resource_id}"
path_part = "{testid}"
}
resource "aws_api_gateway_method" "sample_get" {
rest_api_id = "${aws_api_gateway_rest_api.test-us-east-1.id}"
resource_id = "${aws_api_gateway_resource.sample_test.id}"
http_method = "GET"
authorization = "NONE"
}
resource "aws_api_gateway_deployment" "Deployment" {
depends_on = ["aws_api_gateway_method.sample_get"]
rest_api_id = "${aws_api_gateway_rest_api.test-us-east-1.id}"
stage_name = "test"
}
resource "aws_api_gateway_integration" "test" {
rest_api_id = "${aws_api_gateway_rest_api.test-us-east-1.id}"
resource_id = "${aws_api_gateway_resource.sample_test.id}"
http_method = "${aws_api_gateway_method.sample_get.http_method}"
integration_http_method = "POST"
type = "AWS"
uri = "arn:aws:apigateway:us-east-1:dynamodb:action/GetItem"
credentials = "${aws_iam_role.apiGatewayDynamoDbAccessRole.arn}"
passthrough_behavior = "WHEN_NO_TEMPLATES"
request_templates = {
"application/json" = <<EOF
{
"TableName": "test_tf",
"Key":
{
"test_tf":
{
"S": "$input.params('testid')"
}
}
}
EOF
}
}
resource "aws_iam_policy" "api_dbaccess_policy" {
name = "api_dbaccess_policy"
policy = "${file("api-dynamodb-policy.json")}"
depends_on = [
"aws_dynamodb_table.us-east-1"
]
}
resource "aws_iam_role" "apiGatewayDynamoDbAccessRole" {
name = "apiGatewayDynamoDbAccessRole"
assume_role_policy = "${file("assume-role-policy.json")}"
depends_on = [
"aws_dynamodb_table.us-east-1"
]
}
resource "aws_iam_policy_attachment" "api-dbaccess-policy-attach" {
name = "api-dbaccess-policy-attachment"
roles = ["${aws_iam_role.apiGatewayDynamoDbAccessRole.name}"]
policy_arn = "${aws_iam_policy.api_dbaccess_policy.arn}"
}
resource "aws_api_gateway_method_response" "200" {
rest_api_id = "${aws_api_gateway_rest_api.test-us-east-1.id}"
resource_id = "${aws_api_gateway_resource.sample_test.id}"
http_method = "${aws_api_gateway_method.sample_get.http_method}"
status_code = "200"
}
resource "aws_api_gateway_integration_response" "us-east-1-response" {
rest_api_id = "${aws_api_gateway_rest_api.test-us-east-1.id}"
resource_id = "${aws_api_gateway_resource.sample_test.id}"
http_method = "${aws_api_gateway_method.sample_get.http_method}"
status_code = "${aws_api_gateway_method_response.200.status_code}"
response_templates = {
"application/json" = <<EOF
{
#set($sampletest = $input.path('Item.test_tf.S'))
"test": #if ($sampletest && $sampletest != '')
true
#else
false
#end
}
EOF
}
}

Answer 1

Yes, this is possible with Terraform.
In the root module you define 4 AWS providers, giving alias to each one:
provider "aws" {
alias = "oregon"
region = "us-west-2"
}
provider "aws" {
alias = "virginia"
region = "us-east-1"
}
Then, when you instantiate your modules, instead of relying on provider inheritance you pass the provider explicitly by alias:
module "api_gateway" {
source = "./api_gateway"
providers = {
aws = "aws.oregon"
}
}
Rinse and repeat 4 times for each region.
You can find the docs here: https://www.terraform.io/docs/modules/usage.html