Briefly, this error occurs when Elasticsearch is unable to parse the body of a request. This could be due to incorrect syntax, invalid JSON format, or a mismatch between the content type header and the actual content. To resolve this issue, ensure that the body of your request is correctly formatted and matches the content type header. Also, check for any syntax errors or missing elements in your JSON. If the problem persists, consider using a tool to validate your JSON before sending the request.
This guide will help you check for common problems that cause the log ” Failed to extract body. ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: reindex.
Overview
Reindex is the concept of copying existing data from a source index to a destination index which can be inside the same or a different cluster. Elasticsearch has a dedicated endpoint _reindex for this purpose. A reindexing is mostly required for updating mapping or settings.
Examples
Reindex data from a source index to destination index in the same cluster:
POST /_reindex?pretty
{
"source": {
"index": "news"
},
"dest": {
"index": "news_v2"
}
}
Notes
- Reindex API does not copy settings and mappings from the source index to the destination index. You need to create the destination index with the desired settings and mappings before you begin the reindexing process.
- The API exposes an extensive list of configuration options to fetch data from the source index, such as query-based indexing and selecting multiple indices as the source index.
- In some scenarios reindex API is not useful, where reindexing requires complex data processing and data modification based on application logic. In this case, you can write your custom script using Elasticsearch scroll API to fetch the data from source index and bulk API to index data into destination index.
Log Context
Log “Failed to extract body.” class name is RemoteScrollableHitSource.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :
status = RestStatus.INTERNAL_SERVER_ERROR;
}
try {
return new ElasticsearchStatusException(messagePrefix + bodyMessage(entity); status; cause);
} catch (IOException ioe) {
ElasticsearchStatusException e = new ElasticsearchStatusException(messagePrefix + "Failed to extract body."; status; cause);
e.addSuppressed(ioe);
return e;
}
}
