VoyagerLogger

A lightweight, Sendable-safe Swift logging package for Apple platforms.

Overview

VoyagerLogger provides a small LogDestination protocol with convenience APIs for common log levels, and an AppLogger composite that fans out messages to multiple destinations.

Built-in Destinations

Destination	Purpose
OSLogDestination	Unified Logging via os.Logger
RollingFileDestination	Size-based rolling file logs
NullDestination	No-op (silences logging)
SpyDestination	Captures entries for tests

Log File Export

LogFileExporter collects .log files and exports them as a merged text file or zip archive for sharing and support workflows.

Usage

let logger = AppLogger(destinations: [
    OSLogDestination(subsystem: "com.app", category: "ui"),
    RollingFileDestination(directory: logsURL)
])

logger.info("App launched")
logger.warning("Low memory")
logger.error("Something failed", meta: [.retry: true])

Message Formatting

OSLogDestination and RollingFileDestination accept a shared LogMessageFormat so you can choose which parts of the rendered log line appear and in what order.

Available components:

• .timestamp — bracketed date/time, e.g. [2026-04-11 10:30:00]
• .level — log level label, e.g. ERROR
• .callSite — file, function, and line combined, e.g. MyFile.doWork():42
• .message — the log message itself

Built-in defaults:

• LogMessageFormat.osLogDefault — [.callSite, .message]
• LogMessageFormat.rollingFileDefault — [.timestamp, .level, .callSite, .message]

Customize OSLogDestination formatting:

let console = OSLogDestination(
    subsystem: "com.app",
    category: "network",
    format: LogMessageFormat(
        components: [.level, .message, .callSite],
        separator: " | "
    )
)

Customize RollingFileDestination formatting:

let fileLogger = try RollingFileDestination(
    configuration: .init(
        directory: logsURL,
        format: LogMessageFormat(
            components: [.timestamp, .message, .level],
            separator: " "
        )
    )
)

Extensible Metadata Keys

LogMetadata uses type-safe, extensible keys instead of raw strings:

extension LogMetadataKey {
    static let retry = LogMetadataKey(rawValue: "retry")
    static let errorCode = LogMetadataKey(rawValue: "errorCode")
}

logger.error("Network timeout", meta: [.retry: true, .errorCode: 408])

Custom Destinations

Conform to LogDestination to create your own:

struct MyDestination: LogDestination {
    func log(
        _ level: LogLevel,
        message: @autoclosure () -> any Sendable,
        info: LogInfo?,
        meta: LogMetadata,
        file: String,
        function: String,
        line: Int
    ) {
        // your logging logic
    }
}

Requirements

• Swift 6.0+
• iOS 16+ / macOS 13+ / tvOS 16+ / Mac Catalyst 16+