🔍 Logger

Simple console logger

Features

• 4 levels of severity (🔴 error, 🟠 warning, 🔵️ debug, 🟣 info)
• 9 tag types (📡 network, 🗄 database, 🖥 UI, 💾 file, 🔑 security, 🛍 payment, ⚙️ system, 🧰 util, 📝 other)
• Output to consol, file, or a custom end-point like Google analytics or Firebase crashalytics etc (Use Telemetry for GA)

Why Logger?

• Debugging complex apps efficiently requires filtering to prevent console clutter.
• Fixing network bugs becomes easier when UI and DB logging can be turned off.
• Sending errors to endpoints like Google Analytics or Firebase Crashlytics is beneficial.

Logging format:

Logger.debug(text: "Network.connect - connection established successfully", type: .net)
// Output: [🔵️ Debug] [23-12-24 22:00:45] ➞ 📡 Network.connect: connection established successfully
Logger.warning(text: "Network.connect \(error.localDescription)", type: .net)
// Output: [️🟠 Warning] [23-12-24 22:00:45] ➞ 📡 Network.connect: Wifi not turned on
Logger.error(text: "Network.process-data \(error.localDescription)", type: .net)
// Output: [🔴 Error] [23-12-24 22:00:45] ➞ 📡 Network.process-data: Decoding was unsuccessful. Nothing was saved

Configure:

// Print text format
Logger.config = .plain // .full
// Output transport
Logger.type = .console // .file(filePath), .custom({ level, tag, msg in })
// Levels and tags
Logger.mode = .everything // .nothing, .essential
// Or use this convenient one-liner:
Logger.setup(config: .plain, mode: .everything, type: .console)

Add custom log end-point like GA or Firebase crashalytics

let onLog: LogType.OnLog = { msg, level, _ in
   if [LogLevel.error, .warning].contains(where: { $0 == level }) {
      Swift.print(msg) // Only prints warning and error, replace w/ call to GA etc
   }
}
Logger.type = .custom(onLog) // Add the custom output closure to the logger
Logger.warn("Uh-Oh something went wrong") // Prints
Logger.error("Unsupported format, bail") // Prints
Logger.debug("Entered backround") // Does not print

Note

Since iOS14+ Target apples own Logger class, write: os.Logger

Logging to Console.app

If mesages in console.app only shows messages as private. Read the logger article on eon.codes on how to change that.

import os // Need to import os.Logger

let logger = os.Logger(subsystem: "co.acme.ExampleApp", category: "ExampleApp")
let onLog: LogType.OnLog = { msg, level, _ in
   logger.log("\(msg, privacy: .public)") // Reveals the redacted text from the message
}
Logger.type = .custom(onLog) // Add the custom output closure to the logger
Logger.info("Something happened") // Prints to Console.app (filter by category or subsystem)

Tracing

class Test {
   func myFunction() {
      Trace.trace("This msg")
   }
}
Test().myFunction() // Prints "This msg is called from function: myFunction in class: Test on line: 13"

Trace + Logger

Logger.warn("\(Trace.trace() - error occured", tag: .net) - error occured") // Called inside NetManager.connect
// Prints: [️🟠 Warning] [23-12-24 22:00:45] ➞ 📡 NetManager.connect - error occured

Gotchas

• Print only works when debugging an app. When the app is built for running, Swift.print doesn't work anymore. Use file logging in release if needed.
• Use the Telemetry for GA hook.

Installation

Add the following line to your Package.swift file:

.package(url: "https://github.com/sentryco/Logger", branch: "main")

Then add Logger as a dependency for your targets:

.target(
    name: "MyTarget",
    dependencies: [
        .product(name: "Logger", package: "Logger"),
    ]
),

Todo:

• Consider including the Trace.trace() call in log call so it can be toggled on and off
• Add the tag-type emoji to output just before the message
• Research how to log fatal crashes, if possible. Exception handling needs to be explored
• Conduct more research on logging best practices
• Add terminal color to formatting text: https://github.com/sushichop/Puppy/blob/main/Sources/Puppy/LogColor.swift
• Add native OS support: https://www.avanderlee.com/debugging/oslog-unified-logging/
• Test Firebase Crashlytics in a demo project
• Add support for oslog in the framework. We currently support it in the ad-hoc callback. Add this to unit test as well as instructions on Console.app usage and limitations.
• Consider adding another log type called "important"
• Add usage gif exploring system console, google-analytics, xcode consol