Briefly, this error occurs when Elasticsearch attempts to parse a field expecting a string array, but encounters a null value. This could be due to incorrect data input or mapping. To resolve this, ensure that the data being indexed matches the mapping defined for the field. If the field is optional, consider using the “ignore_malformed” option to ignore such errors. Alternatively, you could check your data source for null values and handle them appropriately before indexing.
This guide will help you check for common problems that cause the log ” could not parse [{}] field. expected a string array but found null value instead ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin.
Log Context
Log “could not parse [{}] field. expected a string array but found null value instead” class name is XContentUtils.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :
public static String[] readStringArray(XContentParser parser; boolean allowNull) throws IOException {
if (parser.currentToken() == XContentParser.Token.VALUE_NULL) {
if (allowNull) {
return null;
}
throw new ElasticsearchParseException("could not parse [{}] field. expected a string array but found null value instead";
parser.currentName());
}
if (parser.currentToken() != XContentParser.Token.START_ARRAY) {
throw new ElasticsearchParseException("could not parse [{}] field. expected a string array but found [{}] value instead";
parser.currentName(); parser.currentToken());
