Swift has great logging built-in, but start with this list of packages if you want to extend or find something specific to your needs.
CocoaLumberjack is a fast, simple, powerful, and flexible, logging framework that allows logging to multiple destinations simultaneously.
Pulseby Alex Grebenyuk
Pulse is a powerful logging system for Apple platforms. It records and inspects logs and network requests, and allows for real-time viewing and sharing.
SwiftLog is a community-driven logging API package for server-side Swift applications. It provides easy logging of messages to a shared destination and supports various logging backends for customization and integration.
Datadogby Datadog, Inc.
This library provides Swift and Objective-C SDKs to interact with Datadog. It includes features for log collection, trace collection, and RUM events collection.
SwiftyBeaver is a flexible, colorful, lightweight logging library for Swift. It supports console, file, and cloud destinations and is ideal for server-side Swift.
XCGLoggerby Dave Wood
XCGLogger is a debug log module for Swift projects that allows you to log details to the console (and optionally a file) with additional information such as date, function name, and line number.