hyperledger/fabric · error

error encoding json data

Error message

error encoding json data

What it means

encodeForJSON wraps the Go standard library json.Encoder failure when encoding a string to JSON. It occurs when marshalling a string value into the JSON buffer fails, which is extremely rare because encoding a Go string to JSON practically never errors. The error is wrapped with the message "error encoding json data".

Source

Thrown at core/ledger/kvledger/txmgmt/statedb/statecouchdb/couchdb.go:1786

// encodePathElement uses Golang for url path encoding, additionally:
// '/' is replaced by %2F, otherwise path encoding will treat as path separator and ignore it
// '+' is replaced by %2B, otherwise path encoding will ignore it, while CouchDB will unencode the plus as a space
// Note that all other URL special characters have been tested successfully without need for special handling
func encodePathElement(str string) string {
	u := &url.URL{}
	u.Path = str
	encodedStr := u.EscapedPath() // url encode using golang url path encoding rules
	encodedStr = strings.Replace(encodedStr, "/", "%2F", -1)
	encodedStr = strings.Replace(encodedStr, "+", "%2B", -1)

	return encodedStr
}

func encodeForJSON(str string) (string, error) {
	buf := &bytes.Buffer{}
	encoder := json.NewEncoder(buf)
	if err := encoder.Encode(str); err != nil {
		return "", errors.Wrap(err, "error encoding json data")
	}
	// Encode adds double quotes to string and terminates with \n - stripping them as bytes as they are all ascii(0-127)
	buffer := buf.Bytes()
	return string(buffer[1 : len(buffer)-2]), nil
}

// printDocumentIds is a convenience method to print readable log entries for arrays of pointers
// to couch document IDs
func printDocumentIds(documentPointers []*couchDoc) (string, error) {
	documentIds := []string{}

	for _, documentPointer := range documentPointers {
		docMetadata := &docMetadata{}
		err := json.Unmarshal(documentPointer.jsonValue, &docMetadata)
		if err != nil {
			return "", errors.Wrap(err, "error unmarshalling json data")
		}
		documentIds = append(documentIds, docMetadata.ID)

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Retry the operation; this is a transient/environmental failure.
2. Check peer memory usage and host resources if it recurs.
3. If reproducible, upgrade Go/Fabric version as it indicates an internal bug.

if err != nil {
    if strings.Contains(err.Error(), "error encoding json data") {
        // transient/environmental; retry once after freeing resources
    }
    return err
}

When it happens

Trigger: json.NewEncoder(buf).Encode(str) returns an error inside encodeForJSON; in practice only triggered by a failure writing to the underlying bytes.Buffer (e.g. memory allocation failure).

Common situations: Almost never seen in normal operation; would appear only under severe memory pressure or an OOM condition in the peer process.

Related errors

• too few arguments
• incorrect number of arguments
• connection.json not found in source folder: %s
• Failed opening file %s: %v
• config isn't valid

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/15ee4f5e52e84eb9. Report an issue: GitHub.