This topic describes how to use Alibaba Cloud SDK for Python to create a Destination Network Address Translation (DNAT) entry.

Prerequisites

Before you use Alibaba Cloud SDK for Python, make sure that the following requirements are met:
  • An Alibaba Cloud account and the AccessKey pair are obtained. You can create and view your AccessKey pair on the Security Management page of the Alibaba Cloud Management Console.
  • Make sure that Alibaba Cloud SDK for Python is installed. For more information, see aliyun-python-sdk-vpc 3.0.12.
  • The VPC Python example library is downloaded.
    Go to the directory where the setup.py file is stored, and run the following command to initialize the environment:
    python setup.py install

Background information

The sample code in this topic includes the following operations:
  1. Create a virtual private cloud (VPC) in the China (Shanghai) region.
  2. Create a vSwitch in the VPC.
  3. Create a NAT gateway for the VPC.
  4. Create an elastic IP address (EIP) in the China (Shanghai) region.
  5. Associate the EIP with the NAT gateway.
  6. Create a DNAT entry.
  7. Query the EIP that is associated with the NAT gateway.
  8. Query the NAT gateway.
  9. Delete the DNAT entry.
  10. Disassociate the EIP from the NAT gateway.
  11. Delete the NAT gateway.
  12. Release the EIP.
  13. Delete the vSwitch.
  14. Delete the VPC.

Procedure

  1. In the downloaded SDK directory, open the $aliyun-openapi-python-sdk-examples\sdk_examples\examples\natgw folder.
  2. Open the natgw_snat.py file in your text editor. Set the required parameters, save the configurations, and then exit the editor.
    The following sample code is displayed:
    #encoding=utf-8
    import sys
    import json
    import time
    
    from aliyunsdkcore.acs_exception.exceptions import ServerException, ClientException
    from aliyunsdkvpc.request.v20160428 import CreateNatGatewayRequest
    from aliyunsdkvpc.request.v20160428 import DeleteNatGatewayRequest
    from aliyunsdkvpc.request.v20160428 import DescribeNatGatewaysRequest
    from aliyunsdkvpc.request.v20160428 import CreateForwardEntryRequest
    from aliyunsdkvpc.request.v20160428 import DescribeForwardTableEntriesRequest
    from aliyunsdkvpc.request.v20160428 import DeleteForwardEntryRequest
    from sdk_lib.sdk_vpc import Vpc
    from sdk_lib.sdk_vswitch import VSwitch
    from sdk_lib.sdk_eip import Eip
    from sdk_lib.sdk_cbwp import CommonBandwidthPackage
    from sdk_lib.common_util import CommonUtil
    from sdk_lib.check_status import CheckStatus
    from sdk_lib.exception import ExceptionHandler
    from sdk_lib.consts import *
    
    client = AcsClient(
        'accessKeyId',
        'accessSecret',
        'RegionId'
        #timeout = 35
    )
    
    
    class NatGateway(object):
        def __init__(self, client):
            self.client = client
    
        def create_nat_gateway(self, params):
            """
            create_nat_gateway: Create a NAT gateway.
            """
            try:
                request = CreateNatGatewayRequest.CreateNatGatewayRequest()
                request.set_VpcId(params['vpc_id'])
                response = client.do_action_with_exception(request)
                response_json = json.loads(response)
                # Check whether the NAT gateway is in the Available state.
                if CheckStatus.check_status(TIME_DEFAULT_OUT, DEFAULT_TIME,
                                            self.describe_nat_gateway_status,
                                            AVAILABLE, response_json['NatGatewayId']):
                    return response_json
            except ServerException as e:
                ExceptionHandler.server_exception(e)
            except ClientException as e:
                ExceptionHandler.client_exception(e)
    
        def describe_nat_gateway(self, nat_gateway_id):
            """
            describe_nat_gateway: Query information about the NAT gateway in a specified region.
            """
            try:
                request = DescribeNatGatewaysRequest.DescribeNatGatewaysRequest()
                request.set_NatGatewayId(nat_gateway_id)
                response = client.do_action_with_exception(request)
                response_json = json.loads(response)
                return response_json
            except ServerException as e:
                ExceptionHandler.server_exception(e)
            except ClientException as e:
                ExceptionHandler.client_exception(e)
    
        def delete_nat_gateway(self, params):
            """
            delete_nat_gateway: Delete the NAT gateway.
            """
            try:
                request = DeleteNatGatewayRequest.DeleteNatGatewayRequest()
                request.set_NatGatewayId(params['nat_gateway_id'])
                response = client.do_action_with_exception(request)
                response_json = json.loads(response)
                # Check whether the NAT gateway is in the Available state.
                if CheckStatus.check_status(TIME_DEFAULT_OUT, DEFAULT_TIME * 5,
                                            self.describe_nat_gateway_status,
                                            '', params['nat_gateway_id']):
                    return response_json
            except ServerException as e:
                ExceptionHandler.server_exception(e)
            except ClientException as e:
                ExceptionHandler.client_exception(e)
    
        def describe_nat_gateway_status(self, nat_gateway_id):
            """
            describe_nat_gateway_status: Query the state of the NAT gateway in a specified region.
            """
            response = self.describe_nat_gateway(nat_gateway_id)
            if len(response["NatGateways"]["NatGateway"]) == 0:
                return ''
            return response["NatGateways"]["NatGateway"][0]['Status']
    
        def create_forward_entry(self, params):
            """
            create_forward_entry: Create a DNAT entry.
            """
            try:
                request = CreateForwardEntryRequest.CreateForwardEntryRequest()
                request.set_ForwardTableId(params['forward_table_id'])
                request.set_ExternalIp(params['external_ip'])
                request.set_IpProtocol(params['ip_protocol'])
                request.set_ExternalPort(params['external_port'])
                request.set_InternalIp(params['internal_ip'])
                request.set_InternalPort(params['internal_port'])
                response = client.do_action_with_exception(request)
                response_json = json.loads(response)
                # Check whether the DNAT entry is in the Available state.
                if CheckStatus.check_status(TIME_DEFAULT_OUT, DEFAULT_TIME,
                                            self.describe_forward_status,
                                            AVAILABLE, params['forward_table_id']):
                    return response_json
            except ServerException as e:
                ExceptionHandler.server_exception(e)
            except ClientException as e:
                ExceptionHandler.client_exception(e)
    
        def describe_forward(self, forward_table_id):
            """
            describe_forward: Query information about the DNAT entry in a specified region.
            """
            try:
                request = DescribeForwardTableEntriesRequest.DescribeForwardTableEntriesRequest()
                request.set_ForwardTableId(forward_table_id)
                response = client.do_action_with_exception(request)
                response_json = json.loads(response)
                return response_json
            except ServerException as e:
                ExceptionHandler.server_exception(e)
            except ClientException as e:
                ExceptionHandler.client_exception(e)
    
        def describe_forward_status(self, forward_table_id):
            """
            describe_forward_status: Query the state of the DNAT entry in a specified region.
            """
            response = self.describe_forward(forward_table_id)
            if len(response["ForwardTableEntries"]["ForwardTableEntry"]) == 0:
                return ''
            return response["ForwardTableEntries"]["ForwardTableEntry"][0]['Status']
    
        def delete_forward_entry(self, params):
            """
            delete_forward_entry: Delete the DNAT entry.
            """
            try:
                request = DeleteForwardEntryRequest.DeleteForwardEntryRequest()
                request.set_ForwardTableId(params['forward_table_id'])
                request.set_ForwardEntryId(params['forward_entry_id'])
                response = client.do_action_with_exception(request)
                response_json = json.loads(response)
                # Check whether the DNAT entry is in the Available state.
                if CheckStatus.check_status(TIME_DEFAULT_OUT, DEFAULT_TIME * 5,
                                            self.describe_forward_status,
                                            '', params['forward_table_id']):
                    return response_json
            except ServerException as e:
                ExceptionHandler.server_exception(e)
            except ClientException as e:
                ExceptionHandler.client_exception(e)
    
    
    def main():
        vpc = Vpc(client)
        vswitch = VSwitch(client)
        eip = Eip(client)
        cbwp = CommonBandwidthPackage(client)
        nat_gateway = NatGateway(client)
    
        params = {}
    
        # Create a VPC.
        vpc_json = vpc.create_vpc()
        CommonUtil.log("create_vpc", vpc_json)
    
        # Create a vSwitch.
        params['vpc_id'] = vpc_json['VpcId']
        params['zone_id'] = "cn-hangzhou-d"
        params['cidr_block'] = "172.16.1.0/24"
        vswitch_json = vswitch.create_vswitch(params)
        CommonUtil.log("create_vswitch", vswitch_json)
        params['vswitch_id'] = vswitch_json['VSwitchId']
    
        # Create a NAT gateway.
        nat_gateway_json = nat_gateway.create_nat_gateway(params)
        CommonUtil.log("create_nat_gateway", nat_gateway_json)
    
        # Create an EIP.
        eip_response_json = eip.allocate_eip_address(params)
        CommonUtil.log("allocate_eip_address", eip_response_json)
        params['allocation_id'] = eip_response_json["AllocationId"]
        params['external_ip'] = eip_response_json['EipAddress']
    
        # Associate the EIP with the NAT gateway.
        params['instance_id'] = nat_gateway_json['NatGatewayId']
        params['allocation_id'] = eip_response_json["AllocationId"]
        params['instance_type'] = 'Nat'
        eip_response_json = eip.associate_eip_address(params)
        CommonUtil.log("associate_eip_address eip", eip_response_json)
    
        # Create a DNAT entry.
        params['forward_table_id'] = nat_gateway_json['ForwardTableIds']['ForwardTableId'][0]
        params['ip_protocol'] = 'tcp'
        params['external_port'] = '8080'
        params['internal_port'] = '80'
        params['internal_ip'] = '172.16.1.0'
        forward_entry_json = nat_gateway.create_forward_entry(params)
        CommonUtil.log("create_forward_entry", forward_entry_json)
    
        # Query the EIP.
        eip_response_json = eip.describe_eip_address(params['allocation_id'])
        CommonUtil.log("describe_eip_address", eip_response_json)
    
        # Query the NAT gateway.
        params['nat_gateway_id'] = nat_gateway_json['NatGatewayId']
        nat_gateway_json = nat_gateway.describe_nat_gateway(params['nat_gateway_id'])
        CommonUtil.log("describe_nat_gateway", nat_gateway_json)
    
        # Delete the DNAT entry.
        params['forward_entry_id'] = forward_entry_json['ForwardEntryId']
        forward_entry_json = nat_gateway.delete_forward_entry(params)
        CommonUtil.log("delete_forward_entry", forward_entry_json)
    
        # Disassociate the EIP from the NAT gateway.
        eip_response_json = eip.unassociate_eip_address(params)
        CommonUtil.log("unassociate_eip_address nat", eip_response_json)
    
        # Delete the NAT gateway.
        nat_gateway_json = nat_gateway.delete_nat_gateway(params)
        CommonUtil.log("delete_nat_gateway", nat_gateway_json)
    
        # Release the EIP.
        eip_response_json = eip.release_eip_address(params)
        CommonUtil.log("release_eip_address", eip_response_json)
    
        # Delete the vSwitch.
        params['vswitch_id'] = vswitch_json['VSwitchId']
        vswitch_json = vswitch.delete_vswitch(params)
        CommonUtil.log("delete_vswitch", vswitch_json)
    
        # Delete the VPC.
        vpc_json = vpc.delete_vpc(params)
        CommonUtil.log("delete_vpc", vpc_json)
    
    
    if __name__ == "__main__":
        sys.exit(main())
  3. Go to the directory where the natgw_snat.py file is stored, and run the following command to create a DNAT entry:
    python natgw_dnat.py

Result

The following output is displayed:
---------------------------create_vpc---------------------------
{
  "ResourceGroupId": "rg-acfmxazxxxxxxxx",
  "RouteTableId": "vtb-uf63rln6gbb50xxxxxxxx",
  "VRouterId": "vrt-uf6p1hfo0ho8gxxxxxxxx",
  "VpcId": "vpc-uf6c3r8yca7dhxxxxxxxx",
  "RequestId": "1F97FC59-77DF-4D76-BE62-0A13EB4E614C"
}

---------------------------create_vswitch---------------------------
{
  "VSwitchId": "vsw-uf6liy66d9ssuxxxxxxxx",
  "RequestId": "88CCCFED-1448-49D2-8550-71952981A47A"
}

---------------------------create_nat_gateway---------------------------
{
  "NatGatewayId": "ngw-uf6aolgwhssvsxxxxxxxx",
  "BandwidthPackageIds": {
    "BandwidthPackageId": []
  },
  "ForwardTableIds": {
    "ForwardTableId": [
      "ftb-uf6unjiun4i12xxxxxxxx"
    ]
  },
  "RequestId": "62A58351-D608-43A4-849E-1E177E917BEA",
  "SnatTableIds": {
    "SnatTableId": [
      "stb-uf65utljwcdkpxxxxxxxx"
    ]
  }
}

---------------------------allocate_eip_address---------------------------
{
  "EipAddress": "101.xx.xx.110",
  "ResourceGroupId": "rg-acfmxazxxxxxxxx",
  "RequestId": "0565295E-2F49-4511-93BC-747A2D19A6BD",
  "AllocationId": "eip-uf683xrl32ge8xxxxxxxx"
}

---------------------------associate_eip_address eip---------------------------
{
  "RequestId": "8759FCE8-F8C2-4372-91D5-7A25D43FD78C"
}

---------------------------create_forward_entry---------------------------
{
  "ForwardEntryId": "fwd-uf6ng3wt8sfwmxxxxxxxx",
  "RequestId": "CC81BCF6-2F64-40CF-85B0-676A83AC3902"
}

---------------------------describe_eip_address---------------------------
{
  "TotalCount": 1,
  "PageNumber": 1,
  "PageSize": 10,
  "EipAddresses": {
    "EipAddress": [
      {
        "ISP": "BGP",
        "ExpiredTime": "",
        "InternetChargeType": "PayByBandwidth",
        "IpAddress": "101.xx.xx.110",
        "AllocationId": "eip-uf683xrl32ge8xxxxxxxx",
        "PrivateIpAddress": "",
        "Status": "InUse",
        "BandwidthPackageId": "",
        "InstanceId": "ngw-uf6aolgwhssvsxxxxxxxx",
        "InstanceRegionId": "cn-shanghai",
        "RegionId": "cn-shanghai",
        "AvailableRegions": {
          "AvailableRegion": [
            "cn-shanghai"
          ]
        },
        "ResourceGroupId": "rg-acfmxazxxxxxxxx",
        "HasReservationData": false,
        "InstanceType": "Nat",
        "AllocationTime": "2019-04-24T10:56:53Z",
        "Name": "",
        "OperationLocks": {
          "LockReason": []
        },
        "Mode": "NAT",
        "BandwidthPackageType": "",
        "BandwidthPackageBandwidth": "",
        "Bandwidth": "5",
        "HDMonitorStatus": "OFF",
        "ChargeType": "PostPaid",
        "SecondLimited": false,
        "Descritpion": ""
      }
    ]
  },
  "RequestId": "CD2B3613-2A99-4687-9C23-A8E9F1F03048"
}

---------------------------describe_nat_gateway---------------------------
{
  "TotalCount": 1,
  "PageNumber": 1,
  "RequestId": "D7519663-8D3B-4CC5-894F-A6798C89688D",
  "PageSize": 10,
  "NatGateways": {
    "NatGateway": [
      {
        "Status": "Available",
        "BandwidthPackageIds": {
          "BandwidthPackageId": []
        },
        "VpcId": "vpc-uf6c3r8yca7dhxxxxxxxx",
        "Description": "",
        "ForwardTableIds": {
          "ForwardTableId": [
            "ftb-uf6unjiun4i12xxxxxxxx"
          ]
        },
        "IpLists": {
          "IpList": [
            {
              "UsingStatus": "UsedByForwardTable",
              "IpAddress": "101.xx.xx.110",
              "AllocationId": "eip-uf683xrl32ge8xxxxxxxx"
            }
          ]
        },
        "BusinessStatus": "Normal",
        "RegionId": "cn-shanghai",
        "CreationTime": "2019-04-24T10:56:50Z",
        "NatGatewayId": "ngw-uf6aolgwhssvsxxxxxxxx",
        "SnatTableIds": {
          "SnatTableId": [
            "stb-uf65utljwcdkpxxxxxxxx"
          ]
        },
        "AutoPay": false,
        "InstanceChargeType": "PostPaid",
        "ExpiredTime": "",
        "Spec": "Small",
        "Name": ""
      }
    ]
  }
}

---------------------------delete_forward_entry---------------------------
{
  "RequestId": "32C76D08-5738-4B07-A638-ACE5F5F5220E"
}

---------------------------unassociate_eip_address nat--------------------------
-
{
  "RequestId": "AE686920-2CD1-4850-AADC-C249484D4B1A"
}

---------------------------delete_nat_gateway---------------------------
{
  "RequestId": "FEBB1E7A-BA5B-4445-B2AB-5B828C17BBE6"
}

---------------------------release_eip_address---------------------------
{
  "RequestId": "812D5E78-5113-4B92-892D-0B293BAD66F6"
}

---------------------------delete_vswitch---------------------------
{
  "RequestId": "8E13EEE4-21B5-4280-B46B-5C168736DC3A"
}

---------------------------delete_vpc---------------------------
{
  "RequestId": "DCBA91E7-F355-4EB6-83E3-27F2E68A8435"
}