# HeliumLogger Provides a lightweight logging implementation for Swift which logs to standard output. ## Features - Logs output to stdout by default. You can change the output stream, see example usage for [`HeliumStreamLogger.use(_:outputStream:)`](http://kitura.github.io/HeliumLogger/Classes/HeliumStreamLogger.html#use). - Different logging levels such as Warning, Verbose, and Error - Enable/disable color output to terminal - Support for the [Kitura `LoggerAPI`](https://github.com/Kitura/LoggerAPI) and [Swift-log `Logging`](https://github.com/apple/swift-log) logging APIs. ## Usage #### Add dependencies Add the `HeliumLogger` package to the dependencies within your application’s `Package.swift` file. Substitute `"x.x.x"` with the latest `HeliumLogger` [release](https://github.com/Kitura/HeliumLogger/releases). ```swift .package(url: "https://github.com/Kitura/HeliumLogger.git", from: "x.x.x") ``` Add `HeliumLogger` to your target's dependencies: ```swift .target(name: "example", dependencies: ["HeliumLogger"]), ``` #### Import packages To use with LoggerAPI: ```swift import HeliumLogger import LoggerAPI ``` To use with swift-log: ```swift import HeliumLogger import Logging ``` #### Initialize HeliumLogger To use HeliumLogger as a logging backend for LoggerAPI: ```swift let logger = HeliumLogger() Log.logger = logger ``` or, if you don't need to customize `HeliumLogger`: ```swift HeliumLogger.use() ``` To use HeliumLogger as a logging backend for swift-log: ```swift let logger = HeliumLogger() LoggingSystem.bootstrap(logger.makeLogHandler) ``` Or, as a convenience: ```swift HeliumLogger.bootstrapSwiftLog() ``` #### Logging levels You can specify the level of output on initialization. You will see output of that level, and all levels below that. The order is: 1. entry (entering a function) 2. exit (exiting a function) 3. debug 4. verbose (default) 5. info 6. warning 7. error For example, this logger will show messages of type `verbose`, `info`, `warning`, and `error`: ```swift let logger = HeliumLogger(.verbose) Log.logger = logger ``` In this example, the logger will only show messages of type `warning` and `error`: ```swift HeliumLogger.use(.warning) ``` Note that when HeliumLogger is used in conjunction with swift-log, the logging level is determined by the `Logger`, and HeliumLogger's own logging level is unused. #### Adjust logging levels at runtime (LoggerAPI) Calling `HeliumLogger.use(LoggerMessageType)` will set the `LoggerAPI` to use this new HeliumLogger instance. If in a route you detect an error with your application, you could use this to dynamically increase the log level. This new instance will not have any customization which you applied to other instances (see list item 7). #### Logging messages (LoggerAPI) How to use HeliumLogger to log messages in your application with LoggerAPI: ```swift Log.verbose("This is a verbose log message.") Log.info("This is an informational log message.") Log.warning("This is a warning.") Log.error("This is an error.") Log.debug("This is a debug message.") ``` #### Further customization ```swift /// Whether, if true, or not the logger output should be colorized. public var colored: Bool = false /// If true, use the detailed format when a user logging format wasn't specified. public var details: Bool = true /// If true, use the full file path, not just the filename. public var fullFilePath: Bool = false /// If not nil, specifies the user specified logging format. /// For example: "[(%date)] [(%type)] [(%file):(%line) (%func)] (%msg)" public var format: String? /// If not nil, specifies the format used when adding the date and the time to the logged messages. public var dateFormat: String? /// If not nil, specifies the timezone used in the date time format. public var timeZone: TimeZone? ``` ## API documentation For more information visit our [API reference](http://kitura.github.io/HeliumLogger/). ## 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/HeliumLogger/blob/master/LICENSE.txt).