feat: Datadog-style visual overhaul + parsing fixes (v0.2.0)

[JasonSatti]

Summary

Full review pass over the formatter: fixes eight correctness bugs (several reachable from the README's own advertised use cases) and overhauls the visuals toward the Datadog Log Explorer aesthetic — a status-colored edge bar on every row, an adaptive column layout that eliminates fixed-width dead space, a truecolor palette with 256-color fallback, and an opt-in --badges chip style. Bumps to v0.2.0.

cat examples/example.log | clogs:

Correctness fixes

Bug	Fix
Return values with a nested object as the last key broke the return block — a bare } line terminated the JSON buffer early	Brace-depth tracking outside string literals replaces the bare-closer check; raw fallbacks also keep original indentation
CRITICAL rendered as a misaligned 8-char token in info blue	Aligned red CRIT; long unknown levels truncate to the column width
Real CloudWatch runtime lines (tab-separated, no [Thread - x]) didn't parse	Thread segment optional, tab separators handled
aws logs tail output didn't parse despite the README advertising it	Event-timestamp prefix stripped before classification, then reclassified
Single-line return values (sam local invoke) rendered as dim passthrough	Routed through the same held-slot machinery as multi-line returns
ddtrace banner suppressed as passthrough but rendered in full via INFO:ddtrace._monkey:	Suppressed by message prefix regardless of wire format
Return-block dict values printed as Python repr ({'k': 'v'})	Rendered as JSON
python -m clogs.cli exited silently with no output	__main__ guard + clogs/__main__.py (python -m clogs works)

Review follow-ups (c2f024b)

Addressed from external review:

• WARN/CRIT/FATAL level shorthands map to warning/critical colors instead of falling back to info blue; runtime and stdlib regexes accept WARN.
• aws logs tail-wrapped stdlib lines inherit the event timestamp instead of rendering an empty timestamp column (formats with their own timestamp keep it).
• README startup wording matches the emitted ─── ↑ startup ─── rule.
• run() docstring documents that color/badge styling is process-global formatter state (layout state resets per call).
• from __future__ import annotations in test_cli.py — PEP 604 unions in signatures broke collection on Python 3.9.

Visuals

Row anatomy

• Status-colored left-edge bar (▎) on every log row — Datadog's row border. The bar and the │ gutter rule continue through wrapped messages and tag lines, so a multi-line record reads as one visually-bounded row.
• Tags render inline on one wrapped line under ↳ instead of stacking one per line.
• Error/warn message text is tinted to match its level, so those rows pop the way they do in Datadog.

Adaptive layout

• The location column sizes itself to the longest location actually seen (capped at LOCATION_WIDTH), pre-scanned across the context buffer so the opening burst renders aligned.
• The timestamp column collapses entirely for streams without timestamps (e.g. stdlib-only).

Palette

• Truecolor Datadog-inspired palette when COLORTERM advertises truecolor/24bit; 256-color fallback otherwise. Critical reads hotter than error.
• --badges (opt-in): uniform filled level chips with full words, Datadog status-chip style.
• Block header/footer widths now match; the startup divider reads ─── ↑ startup ─── (it closes the section above it).

CLI behavior

• --color auto/always/never — colors auto-disable when stdout isn't a TTY.
• NO_COLOR is now spec-compliant: only a non-empty value disables color. ⚠️ Minor behavior change from v0.1, where NO_COLOR="" also disabled it.
• Message wrapping honors COLUMNS via shutil.get_terminal_size.

Testing

166 tests passing (was 131). Coverage added for:

• Nested-dict-as-last-key return blocks; indentation preserved in unparseable-buffer fallbacks
• CRITICAL abbreviation, color, and column alignment across rows
• Runtime lines without the thread segment; aws logs tail prefixed JSON/runtime/plain lines
• Single-line return dicts at EOF vs mid-stream
• ddtrace banner via the stdlib-logger format
• Adaptive location width growth/cap; timestamp column collapse and re-pad
• Badge chips: uniform width, centering, badge colors, --color never fallback
• NO_COLOR spec behavior and explicit color override
• Review follow-ups: WARN/FATAL color mapping, [WARN] runtime lines, tail event-timestamp inheritance for stdlib

Test plan

• python -m pytest -q — 166 passed
• ruff check clogs/ tests/ — clean
• Smoke test against examples/example.log (plain + --badges, truecolor + 256-color)
• Real CloudWatch-format runtime lines, nested return payloads, stdlib-only streams
• pip install . and clogs --version / python -m clogs

Notes for review

• Start with clogs/formatter.py (adaptive layout, bar/continuation rendering) and ContextTracker._scan_json_depth in context.py.
• ⚠️ Output format changes: anything parsing clogs output positionally will see the new bar prefix and adaptive column widths.
• examples/after.png is regenerated from the new output.
• No CI runs on this PR (the workflow lands in feat: invocation tracking, traceback rendering, filters, config file, wrapper mode (v0.3.0) #7); verified locally on the suite above. Stacked: feat: invocation tracking, traceback rendering, filters, config file, wrapper mode (v0.3.0) #7 (v0.3.0 features) builds on this branch and is green in CI.

https://claude.ai/code/session_01MgMZvBpttCRAZhsHRhNtBA