terraframe.rb

azs = [:a, :b, :c]

cidr_block_lookup = {
  public: { a: '172.20.0.0/24',
            b: '172.20.1.0/24',
            c: '172.20.2.0/24' },
  private: { a: '172.20.8.0/24',
             b: '172.20.9.0/24',
             c: '172.20.10.0/24' }
}

provider :aws do
  region 'eu-west-1'
  access_key ''
  secret_key ''
end

resource :aws_vpc, :production do
  # tags do
  #   Name 'production'
  # end
  cidr_block '172.20.0.0/20'
end

resource :aws_internet_gateway, :production do
  vpc_id id_of('aws_vpc', 'production')
end

azs.each do |az|
  [:private, :public].each do |type|
    subnet_name = "#{type}-#{az}"

    resource :aws_subnet, subnet_name do
      vpc_id id_of('aws_vpc', :production)
      cidr_block cidr_block_lookup[type][az]
      availability_zone "eu-west-1#{az}"
    end

    resource :aws_route_table, subnet_name do
      vpc_id id_of('aws_vpc', :production)
      route({ cidr_block:"0.0.0.0/0",
              gateway_id: id_of('aws_internet_gateway', 'production')})
    end

    resource :aws_route_table_association, subnet_name do
      route_table_id id_of('aws_route_table', subnet_name)
      subnet_id id_of('aws_subnet', subnet_name)
    end
  end


  resource :aws_security_group, "nat-#{az}" do
    name "nat-#{az}"
    ingress(from_port: 0,
            to_port: 65535,
            protocol: 'tcp',
            cidr_blocks: [output_of('aws_subnet',
                                    "private-#{az}",
                                    :cidr_block)])
  end
end

vpc.tf

{
  "provider": {
    "aws": {
      "region": "eu-west-1",
      "access_key": "",
      "secret_key": ""
    }
  },
  "variable": {
  },
  "resource": {
    "aws_vpc": {
      "production": {
        "tags": {
          "Name": "production"
        },
        "cidr_block": "172.20.0.0/20"
      }
    },
    "aws_internet_gateway": {
      "production": {
        "vpc_id": "${aws_vpc.production.id}"
      }
    },
    "aws_subnet": {
      "private-a": {
        "tags": {
          "Name": "private-a"
        },
        "vpc_id": "${aws_vpc.production.id}",
        "cidr_block": "172.20.8.0/24",
        "availability_zone": "eu-west-1a"
      },
      "public-a": {
        "tags": {
          "Name": "public-a"
        },
        "vpc_id": "${aws_vpc.production.id}",
        "cidr_block": "172.20.0.0/24",
        "availability_zone": "eu-west-1a"
      },
      "private-b": {
        "tags": {
          "Name": "private-b"
        },
        "vpc_id": "${aws_vpc.production.id}",
        "cidr_block": "172.20.9.0/24",
        "availability_zone": "eu-west-1b"
      },
      "public-b": {
        "tags": {
          "Name": "public-b"
        },
        "vpc_id": "${aws_vpc.production.id}",
        "cidr_block": "172.20.1.0/24",
        "availability_zone": "eu-west-1b"
      },
      "private-c": {
        "tags": {
          "Name": "private-c"
        },
        "vpc_id": "${aws_vpc.production.id}",
        "cidr_block": "172.20.10.0/24",
        "availability_zone": "eu-west-1c"
      },
      "public-c": {
        "tags": {
          "Name": "public-c"
        },
        "vpc_id": "${aws_vpc.production.id}",
        "cidr_block": "172.20.2.0/24",
        "availability_zone": "eu-west-1c"
      }
    },
    "aws_route_table": {
      "private-a": {
        "tags": {
          "Name": "private-a"
        },
        "vpc_id": "${aws_vpc.production.id}",
        "route": {
          "cidr_block": "0.0.0.0/0",
          "gateway_id": "${aws_internet_gateway.production.id}"
        }
      },
      "public-a": {
        "tags": {
          "Name": "public-a"
        },
        "vpc_id": "${aws_vpc.production.id}",
        "route": {
          "cidr_block": "0.0.0.0/0",
          "gateway_id": "${aws_internet_gateway.production.id}"
        }
      },
      "private-b": {
        "tags": {
          "Name": "private-b"
        },
        "vpc_id": "${aws_vpc.production.id}",
        "route": {
          "cidr_block": "0.0.0.0/0",
          "gateway_id": "${aws_internet_gateway.production.id}"
        }
      },
      "public-b": {
        "tags": {
          "Name": "public-b"
        },
        "vpc_id": "${aws_vpc.production.id}",
        "route": {
          "cidr_block": "0.0.0.0/0",
          "gateway_id": "${aws_internet_gateway.production.id}"
        }
      },
      "private-c": {
        "tags": {
          "Name": "private-c"
        },
        "vpc_id": "${aws_vpc.production.id}",
        "route": {
          "cidr_block": "0.0.0.0/0",
          "gateway_id": "${aws_internet_gateway.production.id}"
        }
      },
      "public-c": {
        "tags": {
          "Name": "public-c"
        },
        "vpc_id": "${aws_vpc.production.id}",
        "route": {
          "cidr_block": "0.0.0.0/0",
          "gateway_id": "${aws_internet_gateway.production.id}"
        }
      }
    },
    "aws_route_table_association": {
      "private-a": {
        "route_table_id": "${aws_route_table.private-a.id}",
        "subnet_id": "${aws_subnet.private-a.id}"
      },
      "public-a": {
        "route_table_id": "${aws_route_table.public-a.id}",
        "subnet_id": "${aws_subnet.public-a.id}"
      },
      "private-b": {
        "route_table_id": "${aws_route_table.private-b.id}",
        "subnet_id": "${aws_subnet.private-b.id}"
      },
      "public-b": {
        "route_table_id": "${aws_route_table.public-b.id}",
        "subnet_id": "${aws_subnet.public-b.id}"
      },
      "private-c": {
        "route_table_id": "${aws_route_table.private-c.id}",
        "subnet_id": "${aws_subnet.private-c.id}"
      },
      "public-c": {
        "route_table_id": "${aws_route_table.public-c.id}",
        "subnet_id": "${aws_subnet.public-c.id}"
      }
    },
    "aws_security_group": {
      "nat-a": {
        "name": "nat-a",
        "ingress": {
          "from_port": 0,
          "to_port": 65535,
          "protocol": "tcp",
          "cidr_blocks": [
            "${aws_subnet.private-a.cidr_block}"
          ]
        }
      },
      "nat-b": {
        "name": "nat-b",
        "ingress": {
          "from_port": 0,
          "to_port": 65535,
          "protocol": "tcp",
          "cidr_blocks": [
            "${aws_subnet.private-b.cidr_block}"
          ]
        }
      },
      "nat-c": {
        "name": "nat-c",
        "ingress": {
          "from_port": 0,
          "to_port": 65535,
          "protocol": "tcp",
          "cidr_blocks": [
            "${aws_subnet.private-c.cidr_block}"
          ]
        }
      }
    }
  }
}

whats this? Looks a bit like capistrano but slightly different, Chef?