var (
// ErrNoAuthUrl errors occur when the value of the OS_AUTH_URL environment variable cannot be determined. ErrNoAuthUrl = fmt.Errorf("Environment variable OS_AUTH_URL needs to be set.")
// ErrNoUsername errors occur when the value of the OS_USERNAME environment variable cannot be determined. ErrNoUsername = fmt.Errorf("Environment variable OS_USERNAME needs to be set.")
// ErrNoPassword errors occur when the value of the OS_PASSWORD environment variable cannot be determined. ErrNoPassword = fmt.Errorf("Environment variable OS_PASSWORD or OS_API_KEY needs to be set.")
)
AuthOptions fills out a gophercloud.AuthOptions structure with the settings found on the various OpenStack
OS_* environment variables. The following variables provide sources of truth: OS_AUTH_URL, OS_USERNAME,
OS_PASSWORD, OS_TENANT_ID, and OS_TENANT_NAME. Of these, OS_USERNAME, OS_PASSWORD, and OS_AUTH_URL must
have settings, or an error will result. OS_TENANT_ID and OS_TENANT_NAME are optional.
The value of OS_AUTH_URL will be returned directly to the caller, for subsequent use in
gophercloud.Authenticate()'s Provider parameter. This function will not interpret the value of OS_AUTH_URL,
so as a convenient extention, you may set OS_AUTH_URL to, e.g., "rackspace-uk", or any other Gophercloud-recognized
provider shortcuts. For broad compatibility, especially with local installations, you should probably
avoid the temptation to do this.