main.tf

# Create a vpc


resource "aws_vpc" "mod" {
  cidr_block = "${var.cidr}.0.0/16"
  enable_dns_hostnames = "${var.enable_dns_hostnames}"
  enable_dns_support = "${var.enable_dns_support}"
  tags { Name = "${var.name}" }
}


resource "aws_internet_gateway" "mod" {
  vpc_id = "${aws_vpc.mod.id}"
}


### Route tables ###
resource "aws_route_table" "public" {
  vpc_id = "${aws_vpc.mod.id}"
  tags { Name = "${var.name}-public" }
}
resource "aws_route" "public_internet_gateway" {
    route_table_id = "${aws_route_table.public.id}"
    destination_cidr_block = "0.0.0.0/0"
    gateway_id = "${aws_internet_gateway.mod.id}"
}

resource "aws_route_table" "frontend" {
  vpc_id = "${aws_vpc.mod.id}"
  tags { Name = "${var.name}-frontend" }
}
resource "aws_route" "fr" {
    route_table_id = "${aws_route_table.frontend.id}"
    destination_cidr_block = "0.0.0.0/0"
    nat_gateway_id = "${aws_nat_gateway.nat.id}"
}

resource "aws_route_table" "backend" {
  vpc_id = "${aws_vpc.mod.id}"
  tags { Name = "${var.name}-backend" }
}
resource "aws_route" "bk" {
    route_table_id = "${aws_route_table.backend.id}"
    destination_cidr_block = "0.0.0.0/0"
    nat_gateway_id = "${aws_nat_gateway.nat.id}"
}


### SUBNETS ###


resource "aws_subnet" "public" {
  vpc_id = "${aws_vpc.mod.id}"
  #cidr_block = "${lookup(var.public_blocks, concat("zone", count.index))}"
  cidr_block = "${var.cidr}.10${count.index + 1}.0/24"
  availability_zone = "${lookup(var.zones, concat("zone", count.index))}"
  map_public_ip_on_launch = true
  count = "${var.public_count}"
  tags {
    Name = "${var.env}-public-${count.index + 1}"
  } 
}

resource "aws_subnet" "frontend" {
  vpc_id = "${aws_vpc.mod.id}"
  #cidr_block = "${lookup(var.frontend_blocks, concat("zone", count.index))}"
  cidr_block = "${var.cidr}.11${count.index + 1}.0/24"
  availability_zone = "${lookup(var.zones, concat("zone", count.index))}"
  map_public_ip_on_launch = false
  count = "${var.frontend_count}"
  tags {
    Name = "${var.env}-frontend-${count.index + 1}"
  } 
}

resource "aws_subnet" "backend" {
  vpc_id = "${aws_vpc.mod.id}"
  #cidr_block = "${lookup(var.backend_blocks, concat("zone", count.index))}"
  cidr_block = "${var.cidr}.12${count.index + 1}.0/24"
  availability_zone = "${lookup(var.zones, concat("zone", count.index))}"
  map_public_ip_on_launch = false
  count = "${var.backend_count}"
  tags {
    Name = "${var.env}-backend-${count.index + 1}"
  }
}


### Route table Associations ###
resource "aws_route_table_association" "public" {
  count = "${var.public_count}"
  subnet_id = "${element(aws_subnet.public.*.id, count.index)}"
  route_table_id = "${aws_route_table.public.id}"
}

resource "aws_route_table_association" "frontend" {
  count = "${var.frontend_count}"
  subnet_id = "${element(aws_subnet.frontend.*.id, count.index)}"
  route_table_id = "${aws_route_table.frontend.id}"
}

resource "aws_route_table_association" "backend" {
  count = "${var.backend_count}"
  subnet_id = "${element(aws_subnet.backend.*.id, count.index)}"
  route_table_id = "${aws_route_table.backend.id}"
}



# resource "aws_eip" "nat" {
#   vpc   = true
#   count = "${length(compact(split(",", var.public_subnets)))}"
# }
# resource "aws_nat_gateway" "nat" {
#   allocation_id = "${element(aws_eip.nat.*.id, count.index)}"
#   subnet_id     = "${element(split(",", aws_subnet.public.*.id), count.index)}"
#   count         = "${length(compact(split(",", var.public_subnets)))}"
# }

resource "aws_eip" "nat" {
  vpc   = true
#  count = "${var.nat_count}"
}
resource "aws_nat_gateway" "nat" {
  allocation_id = "${aws_eip.nat.id}"
  subnet_id     = "${aws_subnet.public.0.id}"
#  count         = "${var.nat_count}"
}