Logging

Introduction

Nylo Website v7 provides a comprehensive logging system.

Logs are only printed when APP_DEBUG=true in your .env file, keeping production apps clean.

import 'package:nylo_framework/nylo_framework.dart';

// Basic logging
printInfo("Hello World");
printDebug("Debug message");
printError("Error occurred");

Log Levels

Nylo Website v7 supports multiple log levels with colored output:

printDebug("Fetching user ID: 123");
printInfo("App initialized");
printError("Network request failed");

Output example:

[2025-01-27 10:30:45] [debug] Fetching user ID: 123
[2025-01-27 10:30:45] [info] App initialized
[2025-01-27 10:30:46] [error] Network request failed

Log Methods

Basic Logging

// Class methods
printInfo("Information message");
printDebug("Debug message");
printError("Error message");
printJson({"key": "value"});

Error with Stack Trace

Log errors with stack traces for better debugging:

try {
  await someOperation();
} catch (e, stackTrace) {
  printError(e, stackTrace: stackTrace);
}

Force Print Regardless of Debug Mode

Use alwaysPrint: true to print even when APP_DEBUG=false:

printInfo("Critical info", alwaysPrint: true);
printError("Critical error", alwaysPrint: true);

Show Next Log (One-Time Override)

Print a single log when APP_DEBUG=false:

// .env: APP_DEBUG=false

printInfo("This won't print");

showNextLog();
printInfo("This will print"); // Prints once

printInfo("This won't print again");

JSON Logging

Nylo Website v7 includes a dedicated JSON logging method:

Map<String, dynamic> userData = {
  "id": 123,
  "name": "Anthony",
  "email": "anthony@example.com"
};

// Compact JSON
printJson(userData);
// {"id":123,"name":"Anthony","email":"anthony@example.com"}

// Pretty printed JSON
printJson(userData, prettyPrint: true);
// {
//   "id": 123,
//   "name": "Anthony",
//   "email": "anthony@example.com"
// }

Colored Output

Nylo Website v7 uses ANSI colors for log output in debug mode. Each log level has a distinct color for easy identification.

Disable Colors

// Disable colored output globally
NyLogger.useColors = false;

Colors are automatically disabled:

• In release mode
• When the terminal doesn't support ANSI escape codes

Log Listeners

Nylo Website v7 allows you to listen to all log entries in real-time:

// Set up a log listener
NyLogger.onLog = (NyLogEntry entry) {
  print("Log: [${entry.type}] ${entry.message}");

  // Send to crash reporting service
  if (entry.type == 'error') {
    CrashReporter.log(entry.message, stackTrace: entry.stackTrace);
  }
};

NyLogEntry Properties

NyLogger.onLog = (NyLogEntry entry) {
  entry.message;    // The log message
  entry.type;       // Log level (debug, info, warning, error, success, verbose)
  entry.dateTime;   // When the log was created
  entry.stackTrace; // Stack trace (for errors)
};

Use Cases

• Send errors to crash reporting services (Sentry, Firebase Crashlytics)
• Build custom log viewers
• Store logs for debugging
• Monitor app behavior in real-time

// Example: Send errors to Sentry
NyLogger.onLog = (entry) {
  if (entry.type == 'error') {
    Sentry.captureMessage(
      entry.message,
      level: SentryLevel.error,
    );
  }
};

Helper Extensions

Nylo Website provides convenient extension methods for logging:

dump()

Print any value to the console:

String project = 'Nylo';
project.dump(); // 'Nylo'

List<String> seasons = ['Spring', 'Summer', 'Fall', 'Winter'];
seasons.dump(); // ['Spring', 'Summer', 'Fall', 'Winter']

int age = 25;
age.dump(); // 25

// Function syntax
dump("Hello World");

dd() - Dump and Die

Print a value and immediately exit (useful for debugging):

String code = 'Dart';
code.dd(); // Prints 'Dart' and stops execution

// Function syntax
dd("Debug point reached");

Configuration

Environment Variables

Control logging behavior in your .env file:

# Enable/disable all logging
APP_DEBUG=true

DateTime in Logs

Nylo Website can include timestamps in log output. Configure this in your Nylo setup:

// In your boot provider
Nylo.instance.showDateTimeInLogs(true);

Output with timestamps:

[2025-01-27 10:30:45] [info] User logged in

Output without timestamps:

[info] User logged in

Best Practices

1. Use appropriate log levels - Don't log everything as errors
2. Remove verbose logs in production - Keep APP_DEBUG=false in production
3. Include context - Log relevant data for debugging
4. Use structured logging - NyLogger.json() for complex data
5. Set up error monitoring - Use NyLogger.onLog to catch errors

// Good logging practice
NyLogger.info("User ${user.id} logged in from ${device.platform}");
NyLogger.error("API request failed", stackTrace: stackTrace, alwaysPrint: true);
NyLogger.json(response.data, prettyPrint: true);