MetadataDiscovery:           enableWDSEnv,
		SDSFactory:                  sds,
	}
	extractXDSHeadersFromEnv(o)
	return o
}

// Simplified extraction of gRPC headers from environment.
// Unlike ISTIO_META, where we need JSON and advanced features - this is just for small string headers.
func extractXDSHeadersFromEnv(o *istioagent.AgentOptions) {
	envs := os.Environ()
	for _, e := range envs {