Logger

Serinus comes with a built-in text-based logger which is used during application bootstrapping and several other circumstances such as displaying caught exceptions. This functionality is provided through the Logger class.

Usage

The Logger is an implementation of the LoggerService interface. It is a general-purpose class annd exposes the actual logger hiding its implementation. By default the default logger is the ConsoleLogger.

class TestProvider extends Provider with OnApplicationInit {

  final logger = Logger('TestProviderFour');

  TestProvider();

  @override
  Future<void> onApplicationInit() async {
    logger.info('Provider initialized');
  }
}

This will print (if you have the default logger service):

[Serinus] 26252 20/09/2024 17:20:36     INFO [TestProviderFour] Provider initialized

Override the default logger

You can configure the default logger by providing a custom LoggerService implementation to the Logger constructor.

void main() {
  final application = await serinus.createApplication(
    entrypoint: AppModule(), 
    host: InternetAddress.anyIPv4.address, 
    logger: ConsoleLogger(prefix: 'Serinus New Logger')
  );
}

This will change the default logger prefix to Serinus New Logger:

[Serinus New Logger] 26252 20/09/2024 17:20:36     INFO [TestProviderFour] Provider initialized

Custom Logger

You can also create a custom logger by implementing the LoggerService interface.

class CustomLogger implements LoggerService {
  
  /// Implement all the methods of the LoggerService interface

}

void main() {
  final application = await serinus.createApplication(
    entrypoint: AppModule(), 
    host: InternetAddress.anyIPv4.address, 
    logger: CustomLogger()
  );
}

Logger Levels

The logger has several levels of logging, which are:

• none: No logging.
• verbose: Log virtually everything.
• debug: Log debug and higher.
• info: Log info and higher.
• warning: Log warning and higher.
• severe: Log severe and higher.
• shout: Log shout and higher.

You can set the logger level by providing it to the Logger constructor.

void main() {
  final application = await serinus.createApplication(
    entrypoint: AppModule(), 
    host: InternetAddress.anyIPv4.address, 
    logger: ConsoleLogger(
      prefix: 'Serinus New Logger', 
      levels: {LoggerLevel.warning}
    )
  );
}

This will only log warnings and higher:

[Serinus New Logger] 26252 20/09/2024 17:20:36     WARNING [TestProviderFour] Provider initialized

Overriding Log Levels

Serinus allows you to override the log levels of the default logger without having to create a new instance of the logger.

void main() {
  final application = await serinus.createApplication(
    entrypoint: AppModule(), 
    host: InternetAddress.anyIPv4.address, 
    logLevels: {LoggerLevel.warning}
  );
}

If you provide both a custom logger and log levels, the log levels provided to the createApplication method will be ignored.

Also remember that if you do not provide a custom logger nor log levels, the default logger will be used with the info level if in production mode, or the debug level if in development mode.

Console Logger Options

The ConsoleLogger class has several options that can be configured:

• prefix: The prefix of the logger.
• levels: The levels of the logger.
• json: Whether to log in JSON format.
• timestamp: Whether to log the time difference between the current log and the previous log.

INFO

If you set the json option to true, the timestamp option will be ignored.

void main() {
  final application = await serinus.createApplication(
    entrypoint: AppModule(), 
    host: InternetAddress.anyIPv4.address, 
    logger: ConsoleLogger(
      prefix: 'Serinus New Logger', 
      levels: {LoggerLevel.warning}, 
      json: true, 
    )
  );
}

This will log in JSON format:

{"prefix":"Serinus New Logger","pid":"22340","context":"Test","level":"WARNING","message":"Test","time":"2025-02-23T20:14:26.215734"}

Logging Exceptions

You can log exceptions by passing the OptionalParameters class to the logger.

try {
  throw Exception('Test');
} catch (e) {
  logger.severe('An error occurred', OptionalParameters(error: e));
}