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Transforms

Hash

Compute a digest of the whole record or selected fields and store it on a key.

Overview

The Hash transformation computes a hash digest and writes its hex-encoded value to a key, leaving the rest of the record unchanged. It can hash either the entire record or a chosen subset of fields, and supports several algorithms.

• Whole record (no fields) — the record is canonicalized first (object keys sorted recursively), so two records that differ only in key order produce the same digest.
• Selected fields (fields set) — only those field values are hashed. The field list is treated as a set, so ["a","b"] and ["b","a"] produce the same digest.

Common uses are creating a stable fingerprint for correlation, or precomputing a key you later deduplicate on.

Configuration

Argument	Type	Required	Default	Description
key	string	Yes	—	Path where the resulting hex digest is written
algorithm	string	No	sha256	Hash algorithm: md5, sha1, sha256, or xxh128
fields	array of strings	No	[]	Field paths to hash; empty hashes the whole record

Example

Hash the whole record and store the digest under _fingerprint:

Code
{
  "operation": "hash",
  "arguments": {
    "key": "_fingerprint",
    "algorithm": "sha256"
  }
}

Given the input record:

Code
{
  "user": "alice",
  "action": "login"
}

The output adds the digest, leaving the rest untouched:

Code
{
  "user": "alice",
  "action": "login",
  "_fingerprint": "9f2c...hex-digest..."
}

To fingerprint only specific fields, set fields:

Code
{
  "operation": "hash",
  "arguments": {
    "key": "identity_key",
    "algorithm": "xxh128",
    "fields": ["user", "action"]
  }
}

Notes

1. The digest is written as a lowercase hex string; the original fields are left in place.
2. Default algorithm is sha256. Use xxh128 for a fast, non-cryptographic fingerprint.
3. Whole-record hashing is key-order independent (the record is canonicalized first).
4. In fields mode the field list is order-independent; a field that is present as null or "" still counts, but a wholly absent field simply contributes nothing to the digest.
5. The digests shown above are illustrative.