Use SNS topi filters instead of two different topics

Author: stevebux

infrastructure/terraform/components/api/module_sqs_amendments.tf

@@ -0,0 +1,44 @@
+# Queue to transport letter status amendment messages
+module "amendments_queue" {
+  source = "https://github.com/NHSDigital/nhs-notify-shared-modules/releases/download/v2.0.24/terraform-sqs.zip"
+
+  name = "amendments_queue"
+
+  aws_account_id = var.aws_account_id
+  component      = var.component
+  environment    = var.environment
+  project        = var.project
+  region         = var.region
+
+  sqs_kms_key_arn = module.kms.key_arn
+
+  create_dlq          = true
+  sqs_policy_overload = data.aws_iam_policy_document.amendments_queue_policy.json
+}
+
+data "aws_iam_policy_document" "amendments_queue_policy" {
+  version = "2012-10-17"
+  statement {
+    sid    = "AllowSNSToSendMessage"
+    effect = "Allow"
+
+    principals {
+      type        = "Service"
+      identifiers = ["sns.amazonaws.com"]
+    }
+
+    actions = [
+      "sqs:SendMessage"
+    ]
+
+    resources = [
+      "arn:aws:sqs:${var.region}:${var.aws_account_id}:${var.project}-${var.environment}-${var.component}-amendments_queue-queue"
+    ]
+
+    condition {
+      test     = "ArnEquals"
+      variable = "aws:SourceArn"
+      values   = [module.eventsub.sns_topic.arn]
+    }
+  }
+}

infrastructure/terraform/components/api/module_sqs_letter_status_updates.tf

@@ -0,0 +1,11 @@
+resource "aws_sns_topic_subscription" "eventsub_sqs_amendments" {
+  topic_arn            = module.eventsub.sns_topic.arn
+  protocol             = "sqs"
+  endpoint             = module.amendments_queue.sqs_queue_arn
+  raw_message_delivery = true
+
+  filter_policy_scope = "MessageBody"
+  filter_policy = jsonencode({
+    type = [{ prefix = "uk.nhs.notify.supplier-api.letter" }]
+  })
+}

infrastructure/terraform/components/api/sns_topic_subscription_eventsub_sqs_amendments.tf

@@ -1,5 +1,11 @@
 resource "aws_sns_topic_subscription" "eventsub_sqs_letter_updates" {
-  topic_arn = module.eventsub.sns_topic.arn
-  protocol  = "sqs"
-  endpoint  = module.sqs_letter_updates.sqs_queue_arn
+  topic_arn            = module.eventsub.sns_topic.arn
+  protocol             = "sqs"
+  endpoint             = module.sqs_letter_updates.sqs_queue_arn
+  raw_message_delivery = true
+
+  filter_policy_scope = "MessageBody"
+  filter_policy = jsonencode({
+    type = [{ prefix = "uk.nhs.notify.letter-rendering.letter-request.prepared" }]
+  })
 }