This is a fix for #108 (#109)

* Test fixture for partial-subnets

* Update gitignore

* Fix unable to find route table bug

.gitignore

@@ -3,6 +3,10 @@
 *.tfstate.backup
 **/.terraform.lock.hcl
 .terraform/
+**/terraform.tfstate
+**/terraform.tfstate.backup
+**/terraform.tfvars
+**/a.out
 
 # go deps
 vendor/

data.tf

@@ -22,16 +22,6 @@ data "aws_vpc" "peer_vpc" {
   id       = var.peer_vpc_id
 }
 
-# Get all route tables from vpcs
-data "aws_route_tables" "this_vpc_rts" {
-  provider = aws.this
-  vpc_id   = var.this_vpc_id
-}
-data "aws_route_tables" "peer_vpc_rts" {
-  provider = aws.peer
-  vpc_id   = var.peer_vpc_id
-}
-
 # get subnets info
 data "aws_subnet" "this" {
   count    = length(var.this_subnets_ids)
@@ -44,15 +34,69 @@ data "aws_subnet" "peer" {
   id       = var.peer_subnets_ids[count.index]
 }
 
-# Get info for only those route tables associated with the given subnets
-data "aws_route_table" "this_subnet_rts" {
-  count     = length(var.this_subnets_ids)
+
+# Get subnets and route tables from this
+
+# this vpc main route table
+data "aws_route_table" "this_main_route_table" {
   provider  = aws.this
-  subnet_id = var.this_subnets_ids[count.index]
+  vpc_id   = var.this_vpc_id
+  filter {
+    name   = "association.main"
+    values = ["true"]
+  } 
+}
+
+# this subnets
+data "aws_subnets" "this" {
+  provider  = aws.this
+  filter {
+    name   = "vpc-id"
+    values = [var.this_vpc_id]
+  }
+}
+
+# get route tables associated with subnets
+data "aws_route_tables" "this_associated_route_tables" {
+  for_each = { for subnet in data.aws_subnets.this.ids: subnet => subnet }
+  provider = aws.this
+  vpc_id   = var.this_vpc_id
+  filter {
+    name   = "association.subnet-id"
+    values = [each.key]
+  }
+}
+
+
+# Get subnets and route tables from peer
+
+# peer vpc main route table
+data "aws_route_table" "peer_main_route_table" {
+  provider  = aws.peer
+  vpc_id   = var.peer_vpc_id
+  filter {
+    name   = "association.main"
+    values = ["true"]
+  } 
 }
 
-data "aws_route_table" "peer_subnet_rts" {
-  count     = length(var.peer_subnets_ids)
+# peer subnets
+data "aws_subnets" "peer" {
   provider  = aws.peer
-  subnet_id = var.peer_subnets_ids[count.index]
+  filter {
+    name   = "vpc-id"
+    values = [var.peer_vpc_id]
+  }
 }
+
+# get route tables associated with subnets
+data "aws_route_tables" "peer_associated_route_tables" {
+  for_each = { for subnet in data.aws_subnets.peer.ids: subnet => subnet }
+  provider = aws.peer
+  vpc_id   = var.peer_vpc_id
+  filter {
+    name   = "association.subnet-id"
+    values = [each.key]
+  }
+}
+

examples/partial-subnets/main.tf

@@ -0,0 +1,91 @@
+/*
+/ To make it unit testable, get required parameters from vpcs.
+*/
+
+# peer vpc main route table
+data "aws_route_table" "peer_main_route_table" {
+  provider  = aws.peer
+  vpc_id   = var.peer_vpc_id
+  filter {
+    name   = "association.main"
+    values = ["true"]
+  } 
+}
+
+# peer subnets
+data "aws_subnets" "peer" {
+  provider  = aws.peer
+  filter {
+    name   = "vpc-id"
+    values = [var.peer_vpc_id]
+  }
+}
+
+# get route tables associated with subnets
+data "aws_route_tables" "peer_associated_route_tables" {
+  for_each = { for subnet in data.aws_subnets.peer.ids: subnet => subnet }
+  provider = aws.peer
+  vpc_id   = var.peer_vpc_id
+  filter {
+    name   = "association.subnet-id"
+    values = [each.key]
+  }
+}
+
+locals {
+  peer_subnet_route_table_map = {
+    for subnet in data.aws_subnets.peer.ids: 
+      subnet => concat(
+        data.aws_route_tables.peer_associated_route_tables[subnet].ids,
+        [data.aws_route_table.peer_main_route_table.id]
+      )[0]
+  }
+  peer_subnets_associated_map = {
+    for subnet, route_table in local.peer_subnet_route_table_map: 
+      subnet => route_table 
+      if route_table != data.aws_route_table.peer_main_route_table.id
+  }
+
+  peer_subnets_unassociated_map = {
+    for subnet, route_table in local.peer_subnet_route_table_map: 
+      subnet => route_table 
+      if route_table == data.aws_route_table.peer_main_route_table.id
+  }
+  peer_subnet_ids = distinct(concat(
+    try(slice(keys(local.peer_subnets_associated_map), 0, 1), []),
+    try(slice(keys(local.peer_subnets_unassociated_map),0, 1), []), 
+  ))
+  # actually, peer route tables should be detected from peer subnets if specified
+  peer_route_tables = distinct([ for subnet in local.peer_subnet_ids: local.peer_subnet_route_table_map[subnet] ])
+}
+
+
+
+
+module "partial_subnets" {
+
+  source  = "../../"
+  #version = "6.0.0"
+
+  providers = {
+    aws.this = aws.this
+    aws.peer = aws.peer
+  }
+
+  this_vpc_id = var.this_vpc_id
+  peer_vpc_id = var.peer_vpc_id
+
+  auto_accept_peering = true
+  peer_dns_resolution = true
+  this_dns_resolution = true  
+  peer_subnets_ids = length(var.peer_subnets_ids) > 0 ? var.peer_subnets_ids : local.peer_subnet_ids
+  this_subnets_ids = var.this_subnets_ids
+  this_rts_ids = var.this_rts_ids
+  peer_rts_ids = length(var.peer_rts_ids)>0 ? var.peer_rts_ids : local.peer_route_tables
+
+  tags = {
+    Name        = "tf-partial-subnets"
+    Environment = "Test"
+  }
+
+}

examples/partial-subnets/outputs.tf

@@ -0,0 +1,6 @@
+// Required for tests
+
+output "vpc_peering_accept_status" {
+  value = module.partial_subnets.vpc_peering_accept_status
+}
+

examples/partial-subnets/provider.tf

@@ -0,0 +1,20 @@
+provider "aws" {
+  alias = "this"
+  region = var.this_region != "" ? var.this_region : "eu-west-2"
+  assume_role {
+    role_arn     = var.this_assume_role_arn != "" ? var.this_assume_role_arn : null     
+  }
+  access_key = var.aws_this_access_key != "" ? var.aws_this_access_key : null
+  secret_key = var.aws_this_secret_key != "" ? var.aws_this_secret_key : null
+}
+
+provider "aws" {
+  alias = "peer"
+  region = var.peer_region != "" ? var.peer_region : "eu-central-1"
+  assume_role {
+    role_arn     = var.peer_assume_role_arn != "" ? var.peer_assume_role_arn : null
+  }
+  access_key = var.aws_peer_access_key != "" ? var.aws_peer_access_key : null
+  secret_key = var.aws_peer_secret_key != "" ? var.aws_peer_secret_key : null
+}
+

examples/partial-subnets/variables.tf

@@ -0,0 +1,84 @@
+variable this_assume_role_arn {
+  type = string
+  default = ""
+}
+
+variable peer_assume_role_arn {
+  type = string
+  default = ""
+}
+
+variable "aws_this_access_key" {
+  description = "AWS Access Key for requester account"
+  default = ""
+}
+
+variable "aws_this_secret_key" {
+  description = "AWS Secret Key for requester account"
+  default = ""
+}
+
+variable "aws_peer_access_key" {
+  description = "AWS Access Key for accepter account"
+  default = ""
+}
+
+variable "aws_peer_secret_key" {
+  description = "AWS Secret Key for accepter account"
+  default = ""
+}
+
+
+variable this_region {
+  type = string
+  default = "eu-central-1"
+}
+
+variable peer_region {
+  type = string
+  default = "eu-central-1"
+}
+
+variable this_vpc_id {
+  type = string  
+}
+
+variable peer_vpc_id {
+  type = string     
+}
+
+variable "auto_accept_peering" {
+  description = "Auto accept peering connection: bool"
+  type        = bool
+  default     = false
+}
+
+variable "tags" {
+  description = "Tags: map"
+  type        = map(string)
+  default     = {}
+}
+
+variable "peer_subnets_ids" {
+  description = "If communication can only go to some specific subnets of peer vpc. If empty whole vpc cidr is allowed"
+  type        = list(string)
+  default     = []
+}
+
+variable "this_subnets_ids" {
+  description = "If communication can only go to some specific subnets of this vpc. If empty whole vpc cidr is allowed"
+  type        = list(string)
+  default     = []
+}
+
+variable "this_rts_ids" {
+  description = "Allows to explicitly specify route tables for this VPC"
+  type        = list(string)
+  default     = []
+}
+
+variable "peer_rts_ids" {
+  description = "Allows to explicitly specify route tables for peer VPC"
+  type        = list(string)
+  default     = []
+}

locals.tf

@@ -7,11 +7,29 @@ locals {
   same_acount_and_region = local.same_region && local.same_account
 
   # Rout table should either be the one for the vpc, or the ones associated to the subnets if subnets are given
-  this_rts_ids_new = data.aws_route_tables.this_vpc_rts.ids
-  peer_rts_ids_new = data.aws_route_tables.peer_vpc_rts.ids
+  this_subnet_route_table_map = {
+    for subnet in data.aws_subnets.this.ids: 
+      subnet => concat(
+        data.aws_route_tables.this_associated_route_tables[subnet].ids,
+        [data.aws_route_table.this_main_route_table.id]
+      )[0]
+  }
 
-  this_rts_ids = length(var.this_subnets_ids) == 0 ? local.this_rts_ids_new : data.aws_route_table.this_subnet_rts[*].route_table_id
-  peer_rts_ids = length(var.peer_subnets_ids) == 0 ? local.peer_rts_ids_new : data.aws_route_table.peer_subnet_rts[*].route_table_id
+  peer_subnet_route_table_map = {
+    for subnet in data.aws_subnets.peer.ids: 
+      subnet => concat(
+        data.aws_route_tables.peer_associated_route_tables[subnet].ids,
+        [data.aws_route_table.peer_main_route_table.id]
+      )[0]
+  }
+
+  this_rts_ids = length(var.this_subnets_ids) == 0 ? distinct(values(local.this_subnet_route_table_map)) : distinct([
+    for subnet_id in var.this_subnets_ids : local.this_subnet_route_table_map[subnet_id]
+  ])
+
+  peer_rts_ids = length(var.peer_subnets_ids) == 0 ? distinct(values(local.peer_subnet_route_table_map)) : distinct([
+    for subnet_id in var.peer_subnets_ids : local.peer_subnet_route_table_map[subnet_id]
+  ])
 
   # `this_dest_cidrs` represent CIDR of peer VPC, therefore a destination CIDR for this_vpc
   # `peer_dest_cidrs` represent CIDR of this VPC, therefore a destination CIDR for peer_vpc
@@ -43,6 +61,8 @@ locals {
     }
   ]
 
+
+
   # Routes for associated subnets
   this_associated_routes = [
     for pair in setproduct(local.this_rts_ids_hack, local.this_associated_dest_cidrs) : {
@@ -64,4 +84,3 @@ locals {
   create_routes_this            = var.from_this && !local.create_associated_routes_this
   create_routes_peer            = var.from_peer && !local.create_associated_routes_peer
 }
-

test/fixtures/partial-subnets/data.tf

@@ -0,0 +1,17 @@
+data "aws_route_table" "peer_main_route_table" {
+  provider  = aws.peer
+  vpc_id   = aws_vpc.peer.id  
+  filter {
+    name   = "association.main"
+    values = ["true"]
+  } 
+}
+
+data "aws_route_table" "this_main_route_table" {
+  provider  = aws.this
+  vpc_id   = aws_vpc.this.id  
+  filter {
+    name   = "association.main"
+    values = ["true"]
+  } 
+}