alibaba/DataX · error · RuntimeException

dx_digest paras length must be 3

Error message

dx_digest paras length must be 3

What it means

The dx_digest transformer requires exactly 3 parameters; any other count throws RuntimeException('dx_digest paras length must be 3'), which the enclosing catch rewraps as DataXException(TRANSFORMER_ILLEGAL_PARAMETER). Expected paras: columnIndex (Integer), hash type ('md5'|'sha1', case-insensitive), letter case ('toUpperCase'|'toLowerCase'). The message string is then prefixed with 'paras:[...]' when surfaced.

Source

Thrown at core/src/main/java/com/alibaba/datax/core/transport/transformer/DigestTransformer.java:40

    private static final String MD5 = "md5";
    private static final String SHA1 = "sha1";
    private static final String TO_UPPER_CASE = "toUpperCase";
    private static final String TO_LOWER_CASE = "toLowerCase";

    public DigestTransformer() {
        setTransformerName("dx_digest");
    }

    @Override
    public Record evaluate(Record record, Object... paras) {

        int columnIndex;
        String type;
        String charType;

        try {
            if (paras.length != 3) {
                throw new RuntimeException("dx_digest paras length must be 3");
            }

            columnIndex = (Integer) paras[0];
            type = (String) paras[1];
            charType = (String) paras[2];

            if (!StringUtils.equalsIgnoreCase(MD5, type) && !StringUtils.equalsIgnoreCase(SHA1, type)) {
                throw new RuntimeException("dx_digest paras index 1 must be md5 or sha1");
            }
            if (!StringUtils.equalsIgnoreCase(TO_UPPER_CASE, charType) && !StringUtils.equalsIgnoreCase(TO_LOWER_CASE, charType)) {
                throw new RuntimeException("dx_digest paras index 2 must be toUpperCase or toLowerCase");
            }
        } catch (Exception e) {
            throw DataXException.asDataXException(TransformerErrorCode.TRANSFORMER_ILLEGAL_PARAMETER, "paras:" + Arrays.asList(paras) + " => " + e.getMessage());
        }

        Column column = record.getColumn(columnIndex);

View on GitHub (pinned to 80ec23d5c5)

Solutions

1. Supply exactly 3 parameters: column index, md5/sha1, toUpperCase/toLowerCase.
2. Copy the parameter shape from DataX transformer docs/examples.
3. Validate the transformer block length before submitting the job.

Example fix

// before (job.json)
"transformer": [{"name": "dx_digest", "parameter": [0, "md5"]}]

// after
"transformer": [{"name": "dx_digest", "parameter": [0, "md5", "toUpperCase"]}]

Object[] p = {0, "md5", "toUpperCase"};
if (p.length != 3) throw new IllegalArgumentException("dx_digest needs 3 paras");

catch (DataXException e) when TRANSFORMER_ILLEGAL_PARAMETER: fail the job fast with the printed paras list; transformer param errors are not retryable.

When it happens

Trigger: Declaring a transformer in job JSON like {"name":"dx_digest","parameter":[0,"md5"]} (2 params) or with 4 params. Transformer params are parsed from the job's transformer block and passed straight into evaluate().

Common situations: Hand-writing the transformer parameter array; forgetting the third case parameter; assuming defaults exist for omitted params.

Related errors

• dx_digest paras index 1 must be md5 or sha1
• dx_digest paras index 2 must be toUpperCase or toLowerCase
• dx_filter paras must be 3
• dx_filter para 2 can't be null
• dx_pad paras must be 4

AI-assisted analysis of alibaba/DataX@80ec23d5c5 (2026-08-14). Data as JSON: /api/errors/eb4009ff9a50809b. Report an issue: GitHub.