fix: scrub invalid UTF-8 in CloudFront log lines - #2
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CloudFront logs can contain raw invalid UTF-8 that breaks CGI.unescape/split and JSON emit. Scrub with String#scrub while preserving valid Unicode. Co-authored-by: Cursor <cursoragent@cursor.com>
CGI.unescape of values like %E9 yields high bytes that break UTF-8 String#split. Parse as ASCII-8BIT and fall back to ISO-8859-1 so records stay valid UTF-8 for Loki. Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
getulioruiz
approved these changes
Aug 10, 2026
lugomas
approved these changes
Aug 10, 2026
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Summary
process_linewithString#scrubbeforeCGI.unescape/.split("\t").%09→ space handling.0.2.3and document the change inCHANGELOG.md.Why
Some CloudFront access log lines contain raw invalid UTF-8 bytes. On current Ruby this raises
ArgumentError: invalid byte sequence in UTF-8during parse (often surfaced as FluentdS3 GET client error), so the file never emits records.Using only
force_encoding("ASCII-8BIT")avoids the parse error but leaves binary strings that later failJSON.generate(JSON::GeneratorError/Encoding::UndefinedConversionError), so logs still never reach Loki.Test plan
bundle exec rake teston Ruby 2.7.8 — 17 tests / 27 assertions, including new invalid-UTF-8 and Unicode-preservation casesv1.19.2/ Ruby 3.4.8)João/çafé, scrubs0xFF/0x80, and%09regression still passesJSON.generatesucceeds; ASCII-8BIT-only path fails JSON as expectedcf-utf8) → HTTP 204 and query returns the lineNotes for reviewers
Suggested base branch:
develop(repo default).