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:).
• Different logging levels such as Warning, Verbose, and Error
• Enable/disable color output to terminal
• Support for the Kitura LoggerAPI and Swift-log Logging 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.

.package(url: "https://github.com/Kitura/HeliumLogger.git", from: "x.x.x")

Add HeliumLogger to your target’s dependencies:

.target(name: "example", dependencies: ["HeliumLogger"]),

Import packages

To use with LoggerAPI:

import HeliumLogger
import LoggerAPI

To use with swift-log:

import HeliumLogger
import Logging

Initialize HeliumLogger

To use HeliumLogger as a logging backend for LoggerAPI:

let logger = HeliumLogger()
Log.logger = logger

or, if you don’t need to customize HeliumLogger:

HeliumLogger.use()

To use HeliumLogger as a logging backend for swift-log:

let logger = HeliumLogger()
LoggingSystem.bootstrap(logger.makeLogHandler)

Or, as a convenience:

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:

let logger = HeliumLogger(.verbose)
Log.logger = logger

In this example, the logger will only show messages of type warning and error:

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:

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

/// 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.

Community

We love to talk server-side Swift, and Kitura. Join our Slack to meet the team!

License

This library is licensed under Apache 2.0. Full license text is available in LICENSE.