Locating IP addresses for an instance

from enum import Enum
from typing import List

from google.cloud import compute_v1


def get_instance(project_id: str, zone: str, instance_name: str) -> compute_v1.Instance:
    """
    Get information about a VM instance in the given zone in the specified project.

    Args:
        project_id: project ID or project number of the Cloud project you want to use.
        zone: name of the zone you want to use. For example: “us-west3-b”
        instance_name: name of the VM instance you want to query.
    Returns:
        An Instance object.
    """
    instance_client = compute_v1.InstancesClient()
    instance = instance_client.get(
        project=project_id, zone=zone, instance=instance_name
    )

    return instance


class IPType(Enum):
    INTERNAL = "internal"
    EXTERNAL = "external"
    IP_V6 = "ipv6"


def get_instance_ip_address(
    instance: compute_v1.Instance, ip_type: IPType
) -> List[str]:
    """
    Retrieves the specified type of IP address (ipv6, internal or external) of a specified Compute Engine instance.

    Args:
        instance (compute_v1.Instance): instance to get
        ip_type (IPType): The type of IP address to retrieve (ipv6, internal or external).

    Returns:
        List[str]: Requested type IP addresses of the instance.
    """
    ips = []
    if not instance.network_interfaces:
        return ips
    for interface in instance.network_interfaces:
        if ip_type == IPType.EXTERNAL:
            for config in interface.access_configs:
                if config.type_ == "ONE_TO_ONE_NAT":
                    ips.append(config.nat_i_p)
        elif ip_type == IPType.IP_V6:
            for ipv6_config in getattr(interface, "ipv6_access_configs", []):
                if ipv6_config.type_ == "DIRECT_IPV6":
                    ips.append(ipv6_config.external_ipv6)

        elif ip_type == IPType.INTERNAL:
            # Internal IP is directly available in the network interface
            ips.append(interface.network_i_p)
    return ips

import com.google.cloud.compute.v1.AccessConfig;
import com.google.cloud.compute.v1.AccessConfig.Type;
import com.google.cloud.compute.v1.GetInstanceRequest;
import com.google.cloud.compute.v1.Instance;
import com.google.cloud.compute.v1.InstancesClient;
import com.google.cloud.compute.v1.NetworkInterface;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class GetVmAddress {

  public static void main(String[] args) throws IOException {
    // TODO(developer): Replace these variables before running the sample.
    // Project ID or project number of the Google Cloud project you want to use.
    String projectId = "your-project-id";
    // Instance ID of the Google Cloud project you want to use.
    String instanceId = "your-instance-id";
    // IPType you want to search.
    IpType ipType = IpType.INTERNAL;

    getVmAddress(projectId, instanceId, ipType);
  }

  // Retrieves the specified type of IP address
  // (ipv6, internal or external) of a specified Compute Engine instance.
  public static List<String> getVmAddress(String projectId, String instanceId, IpType ipType)
          throws IOException {
    List<String> result = new ArrayList<>();
    Instance instance = getInstance(projectId, instanceId);

    for (NetworkInterface networkInterface : instance.getNetworkInterfacesList()) {
      if (ipType == IpType.EXTERNAL) {
        for (AccessConfig accessConfig : networkInterface.getAccessConfigsList()) {
          if (accessConfig.getType().equals(Type.ONE_TO_ONE_NAT.name())) {
            result.add(accessConfig.getNatIP());
          }
        }
      } else if (ipType == IpType.IP_V6) {
        for (AccessConfig accessConfig : networkInterface.getAccessConfigsList()) {
          if (accessConfig.hasExternalIpv6()
                  && accessConfig.getType().equals(Type.DIRECT_IPV6.name())) {
            result.add(accessConfig.getExternalIpv6());
          }
        }
      } else if (ipType == IpType.INTERNAL) {
        result.add(networkInterface.getNetworkIP());
      }
    }

    return result;
  }

  private static Instance getInstance(String projectId, String instanceId) throws IOException {
    // Initialize client that will be used to send requests. This client only needs to be created
    // once, and can be reused for multiple requests.
    try (InstancesClient instancesClient = InstancesClient.create()) {
      GetInstanceRequest request = GetInstanceRequest.newBuilder()
              .setInstance(instanceId)
              .setProject(projectId)
              .setZone("us-central1-b")
              .build();
      return instancesClient.get(request);
    }
  }

  public enum IpType {
    INTERNAL("internal"),
    EXTERNAL("external"),
    IP_V6("ipv6");

    private final String type;

    IpType(String type) {
      this.type = type;
    }

    public String getType() {
      return type;
    }
  }
}