Add --log-color flag to control ANSI color log output

[zhengxiexie]

✨ What's Changed

Log Color Control

• ANSI color output is now disabled by default in log output
• A new --log-color flag is added to explicitly enable colored log output
• Color is fully decoupled from log level — users opt in via --log-color

Implementation Details

• Added LogColor config variable and --log-color CLI flag (default false) in pkg/config/config.go
• Updated ZapCustomLogger signature to accept enableColor bool parameter
• Set ConsoleWriter.NoColor based on the flag to control zerolog color output
• Guarded FormatLevel and FormatCaller color wrapping with enableColor check
• Widened log level switch from == 2 to >= 2 for TraceLevel mapping
• Registered --log-color flag in all entry points: cmd/main.go, cmd_clean/main.go, test/e2e/main_test.go
• Added unit tests TestGetLogLevel and TestAnsiColorControlledByFlag

🎯 Motivation

ANSI color escape codes were always emitted in log output regardless of log level. This causes garbled text in non-terminal environments such as kubectl logs, log aggregators, and CI pipelines where ANSI codes are not interpreted.

Issue: Log output contains raw ANSI escape sequences (e.g. \033[32m) when viewed in environments that don't support terminal colors, making logs harder to read and parse.

Solution: Make color output opt-in via a dedicated --log-color flag, keeping it independent from log verbosity levels. This is typically used only during local development/debugging where a real terminal is available.

✅ Testing

Unit Tests

• All existing unit tests pass
• Added new test coverage:
  • ✅ TestGetLogLevel - Validates log level calculation for all debug/logLevel combinations (default, debug_flag_only, log_level_1, log_level_3, debug_with_higher_level, debug_with_lower_level)
  • ✅ TestAnsiColorControlledByFlag - Captures log output to buffer and verifies:
    • ✅ color_disabled - No ANSI escape codes when --log-color is not set
    • ✅ color_enabled - ANSI escape codes present when --log-color is set

$ go test ./pkg/logger/ -v -run "TestGetLogLevel|TestAnsiColor"
=== RUN   TestGetLogLevel
=== RUN   TestGetLogLevel/default
=== RUN   TestGetLogLevel/debug_flag_only
=== RUN   TestGetLogLevel/log_level_1
=== RUN   TestGetLogLevel/log_level_3
=== RUN   TestGetLogLevel/debug_with_higher_level
=== RUN   TestGetLogLevel/debug_with_lower_level
--- PASS: TestGetLogLevel (0.00s)
=== RUN   TestAnsiColorControlledByFlag
=== RUN   TestAnsiColorControlledByFlag/color_disabled
=== RUN   TestAnsiColorControlledByFlag/color_enabled
--- PASS: TestAnsiColorControlledByFlag (0.00s)
PASS

🔄 Backward Compatibility

This change is fully backward compatible:

• Default behavior now outputs plain text instead of colored text, which is strictly better for production environments
• Users who want colored output can explicitly opt in with --log-color
• No configuration file changes or API changes required

[zhengxiexie]

/e2e

[codecov-commenter]

Codecov Report

❌ Patch coverage is 64.28571% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 76.58%. Comparing base (0334455) to head (9eab983).

Files with missing lines	Patch %	Lines
cmd_clean/main.go	0.00%	3 Missing ⚠️
cmd/main.go	0.00%	1 Missing ⚠️
pkg/config/config.go	0.00%	1 Missing ⚠️

❌ Your patch status has failed because the patch coverage (64.28%) is below the target coverage (70.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1374      +/-   ##
==========================================
- Coverage   76.65%   76.58%   -0.07%     
==========================================
  Files         151      151              
  Lines       21102    21109       +7     
==========================================
- Hits        16175    16166       -9     
- Misses       3773     3788      +15     
- Partials     1154     1155       +1     

Flag	Coverage Δ
unit-tests	76.58% <64.28%> (-0.07%)	⬇️

Files with missing lines	Coverage Δ
pkg/clean/clean.go	89.28% <100.00%> (ø)
pkg/logger/logger.go	73.91% <100.00%> (-12.30%)	⬇️
cmd/main.go	0.00% <0.00%> (ø)
pkg/config/config.go	70.89% <0.00%> (-0.34%)	⬇️
cmd_clean/main.go	0.00% <0.00%> (ø)

... and 1 file with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[heypnus]

Can we use a individual flag to control the color switch? I feel that we'd better not bind the color with a specific log level..

[zhengxiexie]

ok，done

[zhengxiexie]

/e2e

[zhengxiexie]

/e2e

[yanjunz97]

pass config.LogColor to clean.Clean?

[zhengxiexie]

ok，done

[yanjunz97]

LGTM