NewAuthorizerFromEnvironment() method def from github.com/Azure/go-autorest/autorest/azure/auth package

auth.go

// NewAuthorizerFromEnvironment creates an Authorizer configured from environment variables in the order:
// 1. Client credentials
// 2. Client certificate
// 3. Username password
// 4. MSI
func NewAuthorizerFromEnvironment() (autorest.Authorizer, error) {
	settings, err := getAuthenticationSettings()
	if err != nil {
		return nil, err
	}

	if settings.resource == "" {
		settings.resource = settings.environment.ResourceManagerEndpoint
	}

	return settings.getAuthorizer()
}