.. _envoy_v3_api_file_xds/type/matcher/v3/regex.proto:

Regex matcher (proto)
=====================






.. _envoy_v3_api_msg_.xds.type.matcher.v3.RegexMatcher:

.xds.type.matcher.v3.RegexMatcher
---------------------------------


`[.xds.type.matcher.v3.RegexMatcher proto] <https://github.com/cncf/xds/blob/main/xds/type/matcher/v3/regex.proto#L14>`_

A regex matcher designed for safety when used with untrusted input.



.. code-block:: json
  :force:

  {
    "google_re2": {...},
    "regex": ...
  }

.. _envoy_v3_api_field_.xds.type.matcher.v3.RegexMatcher.google_re2:


google_re2
  (:ref:`.xds.type.matcher.v3.RegexMatcher.GoogleRE2 <envoy_v3_api_msg_.xds.type.matcher.v3.RegexMatcher.GoogleRE2>`, *REQUIRED*) Google's RE2 regex engine.


  

.. _envoy_v3_api_field_.xds.type.matcher.v3.RegexMatcher.regex:


regex
  (`string <https://developers.google.com/protocol-buffers/docs/proto#scalar>`_, *REQUIRED*) The regex match string. The string must be supported by the configured
  engine.


.. _envoy_v3_api_msg_.xds.type.matcher.v3.RegexMatcher.GoogleRE2:

.xds.type.matcher.v3.RegexMatcher.GoogleRE2
-------------------------------------------


`[.xds.type.matcher.v3.RegexMatcher.GoogleRE2 proto] <https://github.com/cncf/xds/blob/main/xds/type/matcher/v3/regex.proto#L33>`_

Google's `RE2 <https://github.com/google/re2>`_ regex engine. The regex
string must adhere to the documented `syntax
<https://github.com/google/re2/wiki/Syntax>`_. The engine is designed to
complete execution in linear time as well as limit the amount of memory
used.

Envoy supports program size checking via runtime. The runtime keys
`re2.max_program_size.error_level` and `re2.max_program_size.warn_level`
can be set to integers as the maximum program size or complexity that a
compiled regex can have before an exception is thrown or a warning is
logged, respectively. `re2.max_program_size.error_level` defaults to 100,
and `re2.max_program_size.warn_level` has no default if unset (will not
check/log a warning).

Envoy emits two stats for tracking the program size of regexes: the
histogram `re2.program_size`, which records the program size, and the
counter `re2.exceeded_warn_level`, which is incremented each time the
program size exceeds the warn level threshold.