Go Module Review: spinner

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🐹 Go Fan Report: github.com/briandowns/spinner

Overview

Module: github.com/briandowns/spinner v1.23.2
Repository: https://github.com/briandowns/spinner (⭐ 2,499 stars)
License: Apache 2.0
Last Updated: January 20, 2025 (6 days ago)

The spinner module is a simple and elegant terminal spinner/progress indicator library with 90+ built-in character sets, extensive color support, and rich customization options. Perfect for CLI applications that need to show progress during long-running operations.

Current Usage in gh-aw

This module is used exceptionally well in gh-aw! The project implements a clean SpinnerWrapper abstraction that handles TTY detection and provides a consistent interface for progress indication across the entire CLI.

Implementation Summary

• Files: Used across 10+ CLI command files
• Wrapper: pkg/console/spinner.go provides SpinnerWrapper with intelligent TTY detection
• Integration: Consistently used for network operations, API calls, and long-running tasks

Current Configuration

// In pkg/console/spinner.go:27
spinner.New(
    spinner.CharSets[14],           // ⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏ (dots)
    100*time.Millisecond,           // Smooth 100ms updates
    spinner.WithWriter(os.Stderr)   // ✅ Best practice: stderr output
)
s.Color("cyan")                     // Cyan color theme
s.Suffix = " " + message            // Dynamic messages
s.FinalMSG = msg + "\n"             // Completion messages

Usage Example

// From pkg/cli/run.go:19
spinner := console.NewSpinner("Cancelling workflow runs...")
spinner.Start()
defer spinner.Stop()

// Dynamic progress updates
for i, run := range runs {
    // ... do work ...
    spinner.UpdateMessage(fmt.Sprintf("Cancelling workflow runs... (%d/%d completed)", i+1, totalRuns))
}

Research Findings

Module Health: ⭐⭐⭐⭐⭐ (Excellent)

Active Development:

• Latest release v1.23.2 published 6 days ago
• Consistently maintained since 2014
• Quick response to security issues and dependency updates

Recent Updates (v1.23.1 → v1.23.2):

v1.23.2 (January 20, 2025)

• Removed format method call (bug fix)

v1.23.1 (June 13, 2024)

• 🔒 Security: Fixed CVE-2022-29526
• 📦 Dependencies: Consolidated to use only golang.org/x/term (removed go-isatty)
• 🎯 Impact: Cleaner dependency tree, better Go ecosystem alignment

Earlier Features:

• Multi-line spinner support ([copilot] output pull request #146)
• ANSI sequence width handling (Implement pull-request output type with enhanced security and update documentation #147) - proper string measurement
• Enable/disable toggle ([claude-test] Pull request not found #144) - runtime control
• WithWriter terminal detection fixes ([claude-test] Status: ERROR #142, Daily Test Coverage Improvement - File Operations and Workflow Validation #149)

Key Features

• 90+ Character Sets: Wide variety of animation styles (arrows, dots, spinners, progress bars, etc.)
• Color Support: Full terminal color palette with attributes (bold, italic, underline, etc.)
• Customization: Adjustable speed, direction, prefix/suffix text
• Final Messages: Display status on completion
• Writer Control: Redirect output (crucial for pipes/redirects)
• Multi-line Support: Spinners can span multiple lines
• ANSI Handling: Correctly measures display width ignoring control sequences

Best Practices Analysis: ⭐⭐⭐⭐⭐ (Perfect)

✅ What gh-aw Does Right

The gh-aw project's usage of spinner is exemplary and should serve as a reference implementation:

1. ✅ Stderr Output: Uses spinner.WithWriter(os.Stderr) - allows piping stdout without interference
2. ✅ TTY Detection: Automatically disables spinner in non-interactive environments
3. ✅ Clean Abstraction: SpinnerWrapper provides consistent interface with proper nil checks
4. ✅ Latest Version: Running v1.23.2 (latest release)
5. ✅ Error Handling: Proper cleanup with Stop() in all error paths
6. ✅ Dynamic Updates: Uses UpdateMessage() for progress indication
7. ✅ Completion Status: Uses FinalMSG for operation results
8. ✅ Consistent Usage: Same pattern across all CLI commands
9. ✅ Security: CVE-2022-29526 fixed in v1.23.1
10. ✅ Minimal Dependencies: Module now uses only golang.org/x/term

Example: Proper Error Path Handling

// From pkg/cli/run.go:26-28
if err != nil {
    cancelLog.Printf("Failed to list workflow runs: %v", err)
    spinner.Stop()  // ✅ Always stops spinner before returning
    return err
}

Improvement Opportunities

🎉 Good News: No Issues Found!

The implementation is production-ready and follows all best practices. The suggestions below are purely optional enhancements for consideration:

💡 Optional Enhancements

1. Custom Branding (Optional)

Idea: Create GitHub-themed character sets for brand consistency

// Example: Custom gh-aw spinner
var GitHubSpinner = []string{"◐", "◓", "◑", "◒"}
var ProgressBar = []string{"▰▱▱▱▱", "▰▰▱▱▱", "▰▰▰▱▱", "▰▰▰▰▱", "▰▰▰▰▰"}

// Current CharSets[14] is excellent though!

Priority: Low - Current choice is excellent

2. Operation Categorization (Optional)

Idea: Use .Prefix to categorize different operation types

s.Prefix = "[API] "   // For API calls
s.Prefix = "[GIT] "   // For git operations  
s.Prefix = "[BUILD] " // For build operations

Priority: Low - Current approach is clear

3. State Checking (Optional)

Idea: Expose .Active() method for debugging

func (s *SpinnerWrapper) IsRunning() bool {
    if s.enabled && s.spinner != nil {
        return s.spinner.Active()
    }
    return false
}

Priority: Low - Rarely needed

4. Variable Speed (Optional)

Idea: Adjust spinner speed based on operation type

// Fast ops: 50ms, Normal: 100ms (current), Long: 200ms
func NewSpinnerWithSpeed(message string, duration time.Duration) *SpinnerWrapper

Priority: Low - 100ms is perfect default

Comparison: Module Features vs. gh-aw Usage

Feature	Available	Used	Notes
Character Sets (90+)	✅	✅	Using CharSets[14] (excellent choice)
Color Support	✅	✅	Cyan theme
WithWriter	✅	✅	Stderr (best practice)
Start/Stop	✅	✅	Core functionality
UpdateMessage (Suffix)	✅	✅	Dynamic progress updates
FinalMSG	✅	✅	Completion messages
Color Attributes	✅	❌	Not needed (simple is better)
Prefix	✅	❌	Could add for categorization
UpdateSpeed	✅	❌	Static speed works great
Reverse	✅	❌	Not needed
Restart	✅	❌	Not needed (create new spinner)
Active()	✅	❌	Could expose for debugging
Multi-line	✅	❌	Not needed currently

Assessment: gh-aw uses exactly the features it needs - no more, no less. Perfect!

Recommendations

Priority: None

Status: ✅ No action required

The current implementation is exemplary. All recommendations below are purely optional:

1. ✨ Consider Custom Branding (Optional): Explore GitHub-themed character sets for visual consistency
2. ✨ Explore Prefix Feature (Optional): Use .Prefix to categorize different operation types
3. ✨ Add State Checking (Optional): Expose .Active() for debugging/logging

Bottom Line: The spinner integration is production-ready and should serve as a reference implementation for other Go CLI projects.

Technical Deep Dive

Why WithWriter(os.Stderr) Matters

Writing to stderr instead of stdout is crucial for CLI tools:

# ✅ Works correctly with gh-aw (spinner writes to stderr)
gh-aw workflow run --json > output.json
# Spinner shows in terminal, JSON goes to file

# ❌ Would break if spinner used stdout
# Spinner output would contaminate the JSON file

This is a critical best practice that gh-aw implements perfectly.

TTY Detection Benefits

The wrapper's TTY detection automatically handles:

# Interactive: Spinner enabled
$ gh-aw workflow run

# Non-interactive: Spinner disabled
$ gh-aw workflow run 2>&1 | tee log.txt
$ gh-aw workflow run < script.sh
$ CI=true gh-aw workflow run

No user configuration needed - it just works!

SpinnerWrapper Implementation Quality

// Clean abstraction with proper nil checks
func (s *SpinnerWrapper) Stop() {
    if s.enabled && s.spinner != nil {  // ✅ Nil-safe
        s.spinner.Stop()
    }
}

// Works correctly even when spinner is disabled
spinner := NewSpinner("test")
spinner.Start()        // No-op if not TTY
spinner.UpdateMessage("update")  // No-op if not TTY
spinner.Stop()         // No-op if not TTY

No panics, no special cases needed in calling code!

Files and Usage Statistics

Direct Import: 1 file

• pkg/console/spinner.go (wrapper implementation)

Indirect Usage: 10+ files

• pkg/cli/workflows.go
• pkg/cli/status_command.go
• pkg/cli/run_command.go
• pkg/cli/run.go
• pkg/cli/mcp_registry.go
• pkg/cli/logs_orchestrator.go
• pkg/cli/logs_download.go
• pkg/cli/logs_github_api.go
• pkg/cli/interactive.go
• pkg/console/spinner_test.go (tests)

Conclusion

Module Health: ⭐⭐⭐⭐⭐ Excellent (actively maintained, security-conscious, stable)
Usage Quality: ⭐⭐⭐⭐⭐ Perfect (exemplary implementation, all best practices)
Required Actions: ✅ None - Implementation is production-ready

The gh-aw project demonstrates textbook-perfect usage of the spinner module. The clean SpinnerWrapper abstraction, proper TTY detection, stderr output, and consistent usage patterns make this a reference implementation that other Go CLI projects should emulate.

Key Takeaway: Sometimes the best report is one that says "everything is perfect, keep doing what you're doing!" 🎉

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Module summary saved to: specs/mods/spinner.md
Reviewed: 2025-12-26
Next module: TBD (based on recent updates)

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