Awesome

swift-log-file

SwiftLog compatible file log handler.

This currently only supports iOS.

Example: Just logging to a file

let logFileURL = URL(/* your local log file here */)
let logger = try FileLogging.logger(label: "Foobar", localFile: logFileURL)
logger.error("Test Test Test")

Example: Logging to both the standard output (Xcode console if using Xcode) and a file.

let logFileURL = try getDocumentsDirectory().appendingPathComponent(logFileName)
let fileLogger = try FileLogging(to: logFileURL)

LoggingSystem.bootstrap { label in
    let handlers:[LogHandler] = [
        FileLogHandler(label: label, fileLogger: fileLogger),
        StreamLogHandler.standardOutput(label: label)
    ]

    return MultiplexLogHandler(handlers)
}

let logger = Logger(label: "Test")

Note in that last example, if you use LoggingSystem.bootstrap, make sure to create your Logger after the LoggingSystem.bootstrap usage (or you won't get the effects of the LoggingSystem.bootstrap).

Example: Using XCGLogger

XCGLogger supports rotating file logs amongst other features.

let logFileURL = URL(/* your local log file here */)
let xcgLogger = /* Make your XCGLogger, using logFileURL */
let logger = XCGLogging.logger(label: "Test", logger: xcgLogger)
logger.error("Test Test Test")

Example: Logging to both the standard output (Xcode console if using Xcode) and a file using XCGLogger.

let logFileURL = try getDocumentsDirectory().appendingPathComponent(logFileName)
let xcgLogger = /* Make your XCGLogger, using logFileURL */

LoggingSystem.bootstrap { label in
    let handlers:[LogHandler] = [
        XCGLoggerHandler(label: label, logger: xcgLogger),
        StreamLogHandler.standardOutput(label: label)
    ]

    return MultiplexLogHandler(handlers)
}

let logger = Logger(label: "Test")

For more examples, see the unit tests and refer to apple/swift-log's README