func awsData(client *amazon.Client, instanceId string) (i *instance, err error) { i = &instance{} i.ec2, err = client.InstanceByID(instanceId) if err != nil { return nil, err } i.status, err = client.InstanceStatusByID(instanceId) if err != nil { return nil, err } if len(i.ec2.BlockDeviceMappings) != 0 { i.volume, err = client.VolumeByID(aws.StringValue(i.ec2.BlockDeviceMappings[0].Ebs.VolumeId)) if err != nil { return nil, err } } return i, nil }