Simple Swift Logger

Logger.swift

import Foundation

public final class Logger {

    public enum Level: String {
        case verbose = "◻️"
        case debug   = "◼️"
        case info    = "🔹"
        case warning = "🔸"
        case error   = "🔴"
    }

    public static let shared = Logger()

    public func log(_ message: @autoclosure () -> Any,
                    level: Level = .verbose,
                    file: StaticString = #file,
                    function: StaticString = #function,
                    line: UInt = #line) {

        #if DEBUG
        print("\(timestamp()) \(threadName()) \(level.rawValue) \(message()) [\(source(file, function, line))]")
        #endif
    }

    private lazy var dateFormatter: DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateFormat = "HH:mm:ss.SSS"
        return formatter
    }()

    private func timestamp() -> String {
        return dateFormatter.string(from: Date())
    }

    private func threadName() -> String {
        if Thread.isMainThread {
            return "main"
        } else if let name = Thread.current.name, !name.isEmpty {
            return name
        } else {
            return String(format: "%p", Thread.current)
        }
    }

    private func source(_ file: StaticString, _ function: StaticString, _ line: UInt) -> String {
        let url = URL(fileURLWithPath: String(describing: file))
        let filename = url.deletingPathExtension().lastPathComponent
        return "\(filename).\(function):\(line)"
    }
}

// MARK: Convenience free functions

public func log(_ message: @autoclosure () -> Any,
                level: Logger.Level = .verbose,
                file: StaticString = #file,
                function: StaticString = #function,
                line: UInt = #line) {

    Logger.shared.log(message, level: .verbose, file: file, function: function, line: line)
}

public func debug(_ message: @autoclosure () -> Any,
                  file: StaticString = #file,
                  function: StaticString = #function,
                  line: UInt = #line) {

    Logger.shared.log(message, level: .debug, file: file, function: function, line: line)
}

public func info(_ message: @autoclosure () -> Any,
                 file: StaticString = #file,
                 function: StaticString = #function,
                 line: UInt = #line) {

    Logger.shared.log(message, level: .info, file: file, function: function, line: line)
}

public func warn(_ message: @autoclosure () -> Any,
                 file: StaticString = #file,
                 function: StaticString = #function,
                 line: UInt = #line) {

    Logger.shared.log(message, level: .warning, file: file, function: function, line: line)
}

public func error(_ message: @autoclosure () -> Any,
                  file: StaticString = #file,
                  function: StaticString = #function,
                  line: UInt = #line) {

    Logger.shared.log(message, level: .error, file: file, function: function, line: line)
}