regex_path

regex_path rewrites r.URL.Path with Go's regexp.ReplaceAllString.

server:
  http:
    middlewares:
      kv2_path:
        regex_path:
          regex: ^/v1/secret/data/(.*)$
          replacement: /v1/secret/kv2/data/$1

The rewritten path is passed to the next middleware in the chain.