in flink-connector-elasticsearch-base/src/main/java/org/apache/flink/connector/elasticsearch/lookup/ElasticsearchRowDataLookupFunction.java [128:142]
public void open(FunctionContext context) throws Exception {
this.client = callBridge.createClient(networkClientConfig, hosts);
// Set searchRequest in open method in case of amount of calling in eval method when every
// record comes.
this.searchRequest = new SearchRequest(index);
if (type == null) {
searchRequest.types(Strings.EMPTY_ARRAY);
} else {
searchRequest.types(type);
}
searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.fetchSource(producedNames, null);
deserializationSchema.open(null);
}