Occurrence

A swift logging library that integrates with SwiftLog.

Usage

During you app initialization, call Occurrence.bootstrap(). This will configure the Swift LoggingSystem to use Occurrence as a LogHandler.

As a convenience to creating a Logger reference, use the LazyLogger property wrapper which will create a Logger with the specific label (Logger.Subsystem).

@LazyLogger("LoggerLabel") var logger: Logger

Occurrence also offers the ability to observe logging events as they are happening. This can also be useful in the case where entries may need to be proxied to a third-party service.

// Combine
Occurrence.logStreamer
    .publisher
    .sink { entry in
        // process entry
    }

// async/await
let task = Task {
    for await entry in Occurrence.logStreamer.stream {
        // process entry
    }
}

Conveniences

Occurrence has many conveniences to enhance the overall logging experience.

The LoggableError protocol provides a way to easily convert errors to a Logger.Metadata representation. There are also extensions to the Logger instance that allow for passthrough of a LoggableError instance:

@LazyLogger("MyApp") var logger: Logger

enum AppError: LoggableError {
  case badData
}

func throwingFunction() throws {
  guard condition else {
    throw logger.error("Condition not met.", AppError.badData)
  }
}