Update existing attributes in-place

[arielvalentin]

I would like to redact the query string http.target and http.url attributes and the only success I have had so far has been to configure extract, update, and delete actions for each attribute like so:

  attributes:
    actions:
      # removes query strings from http.* attributes
    - key: http.url
      pattern: ^(?P<temp_http_url>.*)\?.*$
      action: extract
    - key: http.url
      from_attribute: temp_http_url
      action: update
    - key: temp_http_url
      action: delete
    - key: http.target
      pattern: ^(?P<temp_http_target>.*)\?.*$
      action: extract
    - key: http.target
      from_attribute: temp_http_target
      action: update
    - key: temp_http_target
      action: delete

I there a more concise or efficient way to accomplish this?

[arielvalentin]

After a few attempts and incantations I found that I am able to use a subset of a regular expression match using replace_pattern.

  transform:
    trace_statements:
      - context: span
        statements:
          - replace_pattern(attributes["http.target"], "\\?.*$", "?[REDACTED]")
          - replace_pattern(attributes["http.url"], "\\?.*$", "?[REDACTED]")

The part that confuses me here is why I had to add additional escaping to the regular expression match.