valueExtractor property

Optional. A value_extractor is required when using a distribution logs-based metric to extract the values to record from a log entry. Two functions are supported for value extraction: EXTRACT(field) or REGEXP_EXTRACT(field, regex). The arguments are:

1. field: The name of the log entry field from which the value is to be extracted.
2. regex: A regular expression using the Google RE2 syntax (https://github.com/google/re2/wiki/Syntax) with a single capture group to extract data from the specified log entry field. The value of the field is converted to a string before applying the regex. It is an error to specify a regex that does not include exactly one capture group.

The result of the extraction must be convertible to a double type, as the distribution always records double values. If either the extraction or the conversion to double fails, then those values are not recorded in the distribution.

Example: REGEXP_EXTRACT(jsonPayload.request, ".*quantity=(\d+).*")