/generators

print() to Logger Migration Guide

Quick Migration Reference

Migration by Context

Debug Output

// Before
print("DEBUG: \(someValue)")
print(">>> \(debugInfo)")

// After
AppLogger.general.debug("\(someValue, privacy: .private)")

Error Logging

// Before
print("Error: \(error)")
print("Failed to load: \(error.localizedDescription)")

// After
AppLogger.general.error("Failed to load: \(error.localizedDescription)")

Network Debugging

// Before
print("Request: \(url)")
print("Response: \(statusCode)")
print("Body: \(responseBody)")

// After
AppLogger.network.debug("Request: \(url, privacy: .public)")
AppLogger.network.info("Response: \(statusCode, privacy: .public)")
AppLogger.network.debug("Body: \(responseBody, privacy: .private)")

User Data

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

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

State Changes

// Before
print("State changed to: \(newState)")

// After
AppLogger.ui.debug("State changed to: \(String(describing: newState), privacy: .public)")

Bulk Migration Strategy

Step 1: Audit Current print() Usage

Run this search to find all print statements:

Grep pattern: print\s*\(

Step 2: Categorize by Purpose

Group print statements by their purpose:

• Debug/Development: → .debug level
• Information: → .info level
• Warnings: → .warning level
• Errors: → .error level

Step 3: Assign Categories

Map to appropriate logger categories:

• Network/API calls → AppLogger.network
• Authentication → AppLogger.auth
• Data operations → AppLogger.data
• UI/Navigation → AppLogger.ui
• General/Other → AppLogger.general

Step 4: Add Privacy Annotations

Review each log for sensitive data:

• User identifiable info → .private
• Passwords/tokens → .sensitive
• IDs, counts, status codes → .public

Common Migration Patterns

Function Entry/Exit

// Before
func processOrder(_ order: Order) {
    print("Processing order: \(order.id)")
    // ... work ...
    print("Order processed")
}

// After
func processOrder(_ order: Order) {
    AppLogger.data.debug("Processing order: \(order.id, privacy: .private(mask: .hash))")
    // ... work ...
    AppLogger.data.info("Order processed: \(order.id, privacy: .private(mask: .hash))")
}

Conditional Logging

// Before
#if DEBUG
print("Debug info: \(value)")
#endif

// After (no #if needed - debug logs are compiled out in release)
AppLogger.general.debug("Debug info: \(value, privacy: .private)")

Error Handling

// Before
do {
    try something()
} catch {
    print("Error: \(error)")
}

// After
do {
    try something()
} catch {
    AppLogger.general.error("Operation failed: \(error.localizedDescription)")
}

Performance Logging

// Before
let start = Date()
// ... work ...
print("Took: \(Date().timeIntervalSince(start))s")

// After
let start = CFAbsoluteTimeGetCurrent()
// ... work ...
let duration = CFAbsoluteTimeGetCurrent() - start
AppLogger.performance.info("Operation took \(duration, format: .fixed(precision: 3))s")

Temporary Migration Helper

If you want to migrate gradually, you can create a temporary bridge:

// TEMPORARY: Remove after full migration
func debugPrint(_ message: String, file: String = #file, line: Int = #line) {
    #if DEBUG
    let filename = (file as NSString).lastPathComponent
    AppLogger.general.debug("[\(filename):\(line)] \(message)")
    #endif
}

// Usage during migration
debugPrint("Old print statement") // Easy to find and replace later

Verification Checklist

After migration:

• No print() statements remain (or only intentional ones)
• All user data has privacy annotations
• Appropriate log levels used
• Categories match the code area
• App builds without warnings
• Logs appear in Console.app with correct subsystem