os_log と Crashlytics を使ったロガークラス

Logger.swift

import Foundation
import os.log
import FirebaseCrashlytics

extension OSLogType: CustomStringConvertible {
    public var description: String {
        switch self {
        case OSLogType.debug: return "🔹🔹🔹"
        case OSLogType.info: return "ℹ️ℹ️ℹ️"
        case OSLogType.error: return "‼️‼️‼️"
        case OSLogType.fault: return "😱😱😱"
        default: return "DEFAULT"
        }
    }
}

// https://github.com/mono0926/mono-kit/blob/master/Lib/Logger.swift
// https://gist.github.com/yoichitgy/8806a7da3a52d8e6f5207e6a1a11b5a8
// https://developer.apple.com/reference/os/logging
struct Logger {
    private static let log = OSLog(subsystem: Bundle.main.bundleIdentifier!, category: "default")

    fileprivate init() {}

    /// Log something at the Debug log level for debug info.
    /// ✅ Console
    /// ❌ CLSLogv
    /// ❌ recordError
    /// ❌ assertionFailure
    func debug(_ message: @autoclosure () -> Any?,
               functionName: CustomStringConvertible = #function,
               fileName: CustomStringConvertible = #file,
               lineNumber: Int = #line) {
        doLog(message(), logType: .debug, functionName: functionName, fileName: fileName, lineNumber: lineNumber)
    }

    /// Log something at the Info log level for trace info.
    /// ✅ Console
    /// ✅ CLSLogv
    /// ❌ recordError
    /// ❌ assertionFailure
    func info(_ message: @autoclosure () -> Any?,
              functionName: CustomStringConvertible = #function,
              fileName: CustomStringConvertible = #file,
              lineNumber: Int = #line) {
        doLog(message(), logType: .info, functionName: functionName, fileName: fileName, lineNumber: lineNumber)
        doCLSLog(message(), logType: .info, functionName: functionName, fileName: fileName, lineNumber: lineNumber)
    }

    /// Log something at the Error log level for handleable error.
    /// ✅ Console
    /// ✅ CLSLogv
    /// ❌ recordError
    /// ❌ assertionFailure
    func error(_ message: @autoclosure () -> Any?,
               functionName: CustomStringConvertible = #function,
               fileName: CustomStringConvertible = #file,
               lineNumber: Int = #line) {
        doLog(message(), logType: .error, functionName: functionName, fileName: fileName, lineNumber: lineNumber)
        doCLSLog(message(), logType: .info, functionName: functionName, fileName: fileName, lineNumber: lineNumber)
    }

    /// Log something at the Fault log level for unexpected error.
    /// ✅ Console
    /// ❌ CLSLogv
    /// ✅ recordError
    /// ✅ assertionFailure
    func fault(_ message: @autoclosure () -> Any?,
               functionName: CustomStringConvertible = #function,
               fileName: CustomStringConvertible = #file,
               lineNumber: Int = #line) {
        doLog(message(), logType: .fault, functionName: functionName, fileName: fileName, lineNumber: lineNumber)
        doCLSRecordError(message(), functionName: functionName, fileName: fileName, lineNumber: lineNumber)
        doAssertionFailure(message())
    }

    func `default`(_ message: @autoclosure () -> Any?,
                   functionName: CustomStringConvertible = #function,
                   fileName: CustomStringConvertible = #file,
                   lineNumber: Int = #line) {
        doLog(message(), logType: .default, functionName: functionName, fileName: fileName, lineNumber: lineNumber)
    }

    fileprivate func doLog(_ message: @autoclosure () -> Any?,
                           logType: OSLogType,
                           functionName: CustomStringConvertible,
                           fileName: CustomStringConvertible,
                           lineNumber: Int) {
        let staticSelf = type(of: self)
        let log = staticSelf.log
        guard log.isEnabled(type: logType) else { return }
        guard let output = staticSelf.buildOutput(message(),
                                                  logType: logType,
                                                  functionName: functionName,
                                                  fileName: fileName,
                                                  lineNumber: lineNumber) else { return }
        os_log("%@", log: log, type: logType, output)
    }

    fileprivate func doCLSLog(_ message: @autoclosure () -> Any?,
                              logType: OSLogType,
                              functionName: CustomStringConvertible,
                              fileName: CustomStringConvertible,
                              lineNumber: Int) {
        let staticSelf = type(of: self)
        guard let output = staticSelf.buildOutput(message(),
                                                  logType: logType,
                                                  functionName: functionName,
                                                  fileName: fileName,
                                                  lineNumber: lineNumber) else { return }
        Crashlytics.crashlytics().log(output)
    }

    fileprivate func doCLSRecordError(_ message: @autoclosure () -> Any?,
                                      functionName: CustomStringConvertible,
                                      fileName: CustomStringConvertible,
                                      lineNumber: Int) {
        let staticSelf = type(of: self)
        guard let error = staticSelf.buildError(message(),
                                                functionName: functionName,
                                                fileName: fileName,
                                                lineNumber: lineNumber) else { return }
        Crashlytics.crashlytics().record(error: error)
    }

    fileprivate func doAssertionFailure(_ message: @autoclosure () -> Any?) {
        guard let message = message() else { return }
        assertionFailure(String(describing: message))
    }

    static func buildOutput(_ message: @autoclosure () -> Any?,
                            logType: OSLogType,
                            functionName: CustomStringConvertible,
                            fileName: CustomStringConvertible,
                            lineNumber: Int) -> String? {
        guard let message = message() else { return nil }
        return "[\(logType)] [\(threadName)] [\((String(describing: fileName) as NSString).lastPathComponent):\(lineNumber)] \(functionName) > \(message)"
    }

    static func buildError(_ message: @autoclosure () -> Any?,
                           functionName: CustomStringConvertible,
                           fileName: CustomStringConvertible,
                           lineNumber: Int) -> Error? {
        guard let message = message() else { return nil }
        return NSError(domain: "\(fileName):\(functionName)", code: lineNumber, userInfo: ["message": message])
    }

    private static var threadName: String {
        if Thread.isMainThread {
            return "main"
        }
        if let threadName = Thread.current.name, !threadName.isEmpty {
            return threadName
        }
        if let queueName = DispatchQueue.currentQueueLabel, !queueName.isEmpty {
            return queueName
        }
        return String(format: "[%p] ", Thread.current)
    }
}

extension DispatchQueue {
    static var currentQueueLabel: String? {
        return String(validatingUTF8: __dispatch_queue_get_label(nil))
    }
}

let log = Logger()

Level	Console	CLSLogv (Crashlytics)	recordError (Crashlytics)	assertionFailure	Use
.debug	o	x	x	x	Debug Info
.info	o	o	x	x	Trace Info
.error	o	o	x	x	Handleable Error
.fault	o	x	o	o	Unexpected Error

updated: 2020-05-07
Fabric SDK => Firebase Crashlytics SDK