# LoggerAPI A logger protocol that provides a common logging interface for different kinds of loggers. In addition, a class with a set of static functions for logging within your code is provided. [Kitura](https://github.com/Kitura/Kitura) uses this API throughout its implementation when logging. ## Usage #### Add dependencies Add the `LoggerAPI` package to the dependencies within your application’s `Package.swift` file. Substitute `"x.x.x"` with the latest `LoggerAPI` [release](https://github.com/Kitura/LoggerAPI/releases): ```swift .package(url: "https://github.com/Kitura/LoggerAPI.git", from: "x.x.x") ``` Add `LoggerAPI` to your target's dependencies: ```swift .target(name: "example", dependencies: ["LoggerAPI"]), ``` #### Import package ```swift import LoggerAPI ```` #### Log messages Add log messages to your application: ```swift Log.warning("This is a warning.") Log.error("This is an error.") ``` #### Define a logger You need to define a `logger` in order to output these messages. You may wish to write your own `Logger` implementation, or you can use `HeliumLogger` that writes to standard output: ```swift import LoggerAPI import HeliumLogger let myLogger = HeliumLogger(.info) Log.logger = myLogger ``` You can find out more about HeliumLogger [here](https://github.com/Kitura/HeliumLogger/blob/master/README.md). #### Logging messages to swift-log You can direct your log messages to be logged via [swift-log](https://github.com/apple/swift-log) by setting the `swiftLogger` property: ```swift import LoggerAPI import Logging let myLogger = Logging.Logger(label: "myLogger") myLogger.logLevel = .notice Log.swiftLogger = myLogger ``` If both `logger` and `swiftLogger` are set, then log messages will be sent to both logging backends. The log level configured for a LoggerAPI Logger and a swift-log Logger are independent, so may be used to log at different levels. Note that because the hierarchy of log levels defined by LoggerAPI and swift-log is slightly different, a mapping is defined between the levels. See the documentation for `Log.isLogging()` for details. ## API documentation For more information visit our [API reference](http://ibm-swift.github.io/LoggerAPI/). ## Community We love to talk server-side Swift, and Kitura. Join our [Slack](http://swift-at-ibm-slack.mybluemix.net/) to meet the team! ## License This library is licensed under Apache 2.0. Full license text is available in [LICENSE](https://github.com/Kitura/LoggerAPI/blob/master/LICENSE.txt).