/logging-setup

name: logging-setup
description: Generates structured logging infrastructure using os.log/Logger to replace print() statements. Use when user wants to add proper logging, replace print statements, or set up app logging.
allowed-tools: [Read, Write, Edit, Glob, Grep, Bash, AskUserQuestion]
last_verified: 2026-07-16
review_by: 2027-06-22
os_version: iOS 27 / macOS 27

Logging Setup Generator

Replace print() statements with Apple's structured logging system (os.log/Logger) for better debugging, privacy controls, and Console.app integration.

When This Skill Activates

Use this skill when the user:

• Asks to "add logging" or "set up logging"
• Wants to "replace print statements"
• Mentions "os.log", "Logger", or "structured logging"
• Asks about "debug logging" or "production logging"
• Wants to audit print() usage in their codebase

Why Logger Over print()

| print() | Logger | |---------|--------| | Always executes | Debug logs compiled out in Release | | No filtering | Filter by subsystem/category in Console.app | | No privacy | .private, .public, .sensitive annotations | | String interpolation always runs | Deferred evaluation (performance) | | Not in Console.app | Full system integration |

Pre-Generation Checks

1. Project Context Detection

• [ ] Check deployment target (Logger requires iOS 14+ / macOS 11+)
• [ ] Search for existing Logger/os.log usage
• [ ] Identify source file locations (Sources/, App/, etc.)

2. Conflict Detection

Search for existing logging:

Glob: **/*Logger*.swift
Grep: "import OSLog" or "os_log"

If found, ask user:

• Extend existing logging?
• Replace with new implementation?
• Create separate logger?

Modes of Operation

Mode 1: Audit

Find all print() statements and report:

Grep: print\s*\(

Report format:

• File:line - print statement
• Severity: Info/Warning/Error (based on context)
• Suggested Logger level

Mode 2: Generate

Create logging infrastructure from scratch.

Mode 3: Migrate

Convert existing print() to Logger with suggestions.

Configuration Questions

Ask user via AskUserQuestion:

1. **Categories needed?**

• Network, Auth, UI, Data (defaults)
• Custom categories?

2. **Include migration helpers?**

• Extension on String for quick migration
• Temporary print-to-log bridge

Generation Process

Step 1: Create AppLogger.swift

Read template from `templates/AppLogger.swift` and customize:

• Set subsystem from Bundle.main.bundleIdentifier
• Add user-specified categories
• Include usage examples in comments

Step 2: Determine File Location

Check project structure:

• If `Sources/` exists → `Sources/Logging/AppLogger.swift`
• If `App/` exists → `App/Logging/AppLogger.swift`
• Otherwise → `Logging/AppLogger.swift`

Step 3: Provide Migration Guidance

Show examples of converting common print patterns:

// Before
print("User logged in: \(email)")

// After
AppLogger.auth.info("User logged in: \(email, privacy: .private)")

Output Format

After generation, provide:

Files Created

• `[Path]/Logging/AppLogger.swift`

Integration Steps

1. Import in files: `import OSLog` (not needed if using AppLogger) 2. Replace print() calls with AppLogger.[category].[level]() 3. Add privacy annotations for sensitive data

Privacy Annotations Guide

• `.public` - Safe to log (IDs, counts, non-sensitive)
• `.private` - Redacted in release (emails, names)
• `.sensitive` - Always redacted (passwords, tokens)

Console.app Usage

1. Open Console.app 2. Filter by subsystem: `com.yourapp` 3. Filter by category: `Network`, `Auth`, etc.

Testing Instructions

1. Add a test log: `AppLogger.general.debug("Test log")` 2. Run app, check Xcode console 3. Open Console.app, filter by your app's subsystem

References

• **logger-patterns.md** - Best practices and privacy levels
• **migration-guide.md** - Converting print() to Logger
• **templates/AppLogger.swift** - Template file