/**
 * Describe Vpcs Action Sample
 * Gives you information about your VPCs. You can filter the results to return
 * information only about VPCs that match criteria you specify. For example,
 * you could ask to get information about a particular VPC or VPCs (or all your VPCs)
 * only if the VPC's state is available. You can specify multiple filters (e.g.,
 * the VPC uses one of several sets of DHCP options, and the VPC's state is available).
 * The result includes information for a particular VPC only if the VPC
 * matches all your filters. If there's no match, no special message is
 * returned; the response is simply empty.  
 * @param Amazon_EC2_Interface $service instance of Amazon_EC2_Interface
 * @param mixed $request Amazon_EC2_Model_DescribeVpcs or array of parameters
 */
function invokeDescribeVpcs(Amazon_EC2_Interface $service, $request)
{
    try {
        $response = $service->describeVpcs($request);
        echo "Service Response\n";
        echo "=============================================================================\n";
        echo "        DescribeVpcsResponse\n";
        if ($response->isSetResponseMetadata()) {
            echo "            ResponseMetadata\n";
            $responseMetadata = $response->getResponseMetadata();
            if ($responseMetadata->isSetRequestId()) {
                echo "                RequestId\n";
                echo "                    " . $responseMetadata->getRequestId() . "\n";
            }
        }
        if ($response->isSetDescribeVpcsResult()) {
            echo "            DescribeVpcsResult\n";
            $describeVpcsResult = $response->getDescribeVpcsResult();
            $vpcList = $describeVpcsResult->getVpc();
            foreach ($vpcList as $vpc) {
                echo "                Vpc\n";
                if ($vpc->isSetVpcId()) {
                    echo "                    VpcId\n";
                    echo "                        " . $vpc->getVpcId() . "\n";
                }
                if ($vpc->isSetVpcState()) {
                    echo "                    VpcState\n";
                    echo "                        " . $vpc->getVpcState() . "\n";
                }
                if ($vpc->isSetCidrBlock()) {
                    echo "                    CidrBlock\n";
                    echo "                        " . $vpc->getCidrBlock() . "\n";
                }
                if ($vpc->isSetDhcpOptionsId()) {
                    echo "                    DhcpOptionsId\n";
                    echo "                        " . $vpc->getDhcpOptionsId() . "\n";
                }
            }
        }
    } catch (Amazon_EC2_Exception $ex) {
        echo "Caught Exception: " . $ex->getMessage() . "\n";
        echo "Response Status Code: " . $ex->getStatusCode() . "\n";
        echo "Error Code: " . $ex->getErrorCode() . "\n";
        echo "Error Type: " . $ex->getErrorType() . "\n";
        echo "Request ID: " . $ex->getRequestId() . "\n";
        echo "XML: " . $ex->getXML() . "\n";
    }
}