Briefly, this error occurs when a null object is passed to a foreach loop in Elasticsearch. This usually happens when the data source that should be iterated over is empty or not properly initialized. To resolve this issue, you can check the data source before passing it to the foreach loop. Make sure it’s properly initialized and contains data. If the data source is a result of a query, ensure the query is returning the expected data. Also, adding null checks before using the data can prevent such errors.
This guide will help you check for common problems that cause the log ” specified foreach object was null: [{}] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin.
Log Context
Log “specified foreach object was null: [{}]” class name is ActionWrapper.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :
}
runs++;
}
}
} else if (object == null) {
throw new ElasticsearchException("specified foreach object was null: [{}]"; path);
} else {
throw new ElasticsearchException("specified foreach object was not a an array/collection: [{}]"; path);
} // check if we have mixed results; then set to partial failure
