lovetodream/swift-log-loki

Grafana Loki Logging for Swift based on swift-log

SwiftLogLoki

This library can be used as an implementation of Apple's swift-log interface that captures console logs from apps or services and sends them to Grafana Loki.

Features

• Supports Linux and all Apple platforms
• Different logging levels such as trace, debug, info, notice, warning, error and critical
• Option to send logs as snappy-compressed Protobuf (default) or JSON
• Send logs in batches via Duration since batch creation, amount of log entries in batch or a mix of both options

Add dependency

Swift Package

Add LoggingLoki to the dependencies within your application's Package.swift file.

.package(url: "https://github.com/lovetodream/swift-log-loki.git", from: "2.0.0"),

Add LoggingLoki to your target's dependencies.

.product(name: "LoggingLoki", package: "swift-log-loki"),

Xcode Project

Go to File > Add Packages, enter the Package URL https://github.com/lovetodream/swift-log-loki.git and press Add Package.

Usage

You can use LoggingLoki as your default Log Handler for swift-log.

import Logging
import LoggingLoki

let processor = LokiLogProcessor(
    configuration: LokiLogProcessorConfiguration(lokiURL: "http://localhost:3100")
)
LoggingSystem.bootstrap { label in
    LokiLogHandler(label: label, processor: processor)
}

try await withThrowingDiscardingTaskGroup { group in
    group.addTask {
        // The processor has to run in the background to send logs to Loki.
        try await processor.run()
    }
}

API documentation

For more information visit the API reference.

License

Apache 2.0

Copyright (c) 2022-present, Timo Zacherl (@lovetodream)

This project contains code written by others not affliated with this project. All copyright claims are reserved by them. For a full list, with their claimed rights, see NOTICE.txt

Swift is a registered trademark of Apple, Inc. Any use of their trademark does not imply any affiliation with or endorsement by them, and all rights are reserved by them.

swift-log-loki's Issues

LokiStream.swift: Reuse NumberFormatter

Hi, I stumbled across this Swift package because I am looking for a similar solution.

I noticed that at one point you create a new NumberFormatter() for each log entry and I would like to kindly suggest that you either pull this out of the compactMap or - better - use a factory for it.

NumberFormatter() are quite expensive to create and it is recommended to reuse them as often as possible.
(see https://sarunw.com/posts/how-expensive-is-dateformatter/)

swift-log-loki/Sources/LoggingLoki/LokiStream.swift

Lines 10 to 16 in fb800a4

	self.values = logs.compactMap { log in
	let formatter = NumberFormatter()
	formatter.numberStyle = .decimal
	formatter.groupingSeparator = ""
	#if os(macOS) || !canImport(Darwin)
	formatter.thousandSeparator = ""
	#endif

One way could be

private class LokiFormatters {
    
    static let decimalFormatter = {
        let formatter = NumberFormatter()
        formatter.numberStyle = .decimal
        formatter.groupingSeparator = ""
        #if os(macOS) || !canImport(Darwin)
        formatter.thousandSeparator = ""
        #endif
        
        return formatter
    }()
    
}


struct LokiStream: Encodable, Sendable {
    var stream: Dictionary<String, String>
    var values: Array<Array<String>>

    init(_ logs: [LokiLog], with labels: LokiLabels) {
        self.stream = labels
        self.values = logs.compactMap { log in
            let timestamp = Int64(log.timestamp.timeIntervalSince1970 * 1_000_000_000) as NSNumber
            guard let formattedTimestamp = LokiFormatters.decimalFormatter.string(from: timestamp) else {
                return nil
            }
            return [formattedTimestamp, log.message]
        }
    }
}

Tag for SPM

main brunch must have tag 0.1.0 for spm