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iOS Guides
Configuring SDL Logging

Configuring SDL Logging

A powerful built-in logging framework is available to make debugging your SDL app easier. It provides many of the features common to other 3rd party logging frameworks for iOS and can be used by your own app as well. We recommend that your app's integration with SDL provide logging using this framework rather than any other 3rd party framework your app may be using or NSLog. This will consolidate all SDL related logs in a common format and to common destinations.

SDL will configure its logging into a production-friendly configuration by default. If you wish to use a debug or a custom configuration, then you will have to specify this yourself. SDLConfiguration allows you to pass a SDLLogConfiguration with custom values. A few of these values will be covered in this section, the others are in their own sections below.

When setting up your SDLConfiguration you can pass a different log configuration:

SDLConfiguration* configuration = [[SDLConfiguration alloc] initWithLifecycle:lifecycleConfiguration lockScreen:[SDLLockScreenConfiguration enabledConfiguration] logging:[SDLLogConfiguration debugConfiguration] fileManager:nil encryption:nil];
let configuration = SDLConfiguration(lifecycle: lifecycleConfiguration, lockScreen: .enabled(), logging: .debug(), fileManager: nil, encryption: nil)

Format Type

Currently, SDL provides three output formats for logs (for example into the console or file log), these are "Simple", "Default", and "Detailed".


09:52:07:324 🔹 (SDL)Protocol  I'm a log!


09:52:07:324 🔹 (SDL)Protocol:SDLV2ProtocolHeader:25  I'm also a log!


09:52:07:324 🔹 DEBUG com.apple.main-thread:(SDL)Protocol:[SDLV2ProtocolHeader parse:]:74  Me three!

Log Synchronicity

The configuration provides two properties, asynchronous and errorsAsynchronous. By default asynchronous is true and errorsAsynchronous is false. This means that any logs that are not logged at the error log level will be logged asynchronously on a separate serial queue, while those on the error log level will be logged synchronously on the separate queue (but the thread that logged it will be blocked until that log completes).

Log level

The globalLogLevel defines which logs will be logged to the target outputs. For example, if you set the log level to debug, all error, warning, and debug level logs will be logged, but verbose level logs will not be logged.

SDLLogLevel Visible Logs
Off none
Error error
Warning error and warning
Debug error, warning and debug
Verbose error, warning, debug and verbose

Although the default log level is defined in the SDLLogLevel enum, it should not be used as a global log level. See the API documentation for more detail.


Targets are the output locations where the log will appear. By default only the OSLog log target will be enabled in both default and debug configurations. You may configure additional pre-built targets or create your own targets and add them.

Apple System Log Target (Deprecated)

The Apple System Logger target, SDLLogTargetAppleSystemLogger is now deprecated in favor of the OS Log target which will do the same thing. It will be removed in a future release. This target will log to the Xcode console and the device console.

OS Log Target

The OSLog target, SDLLogTargetOSLog, is the default log target in both default and debug configurations. For more information on this logging system see Apple's documentation. SDL's OSLog target will take advantage of subsystems and levels to allow you powerful runtime filtering capabilities through the MacOS Console app with a connected device.

File Target

The File target, SDLLogTargetFile, allows you to log messages to a rolling set of files which will be stored on the device, specifically in the Documents/smartdevicelink/log/ folder. The file names will be timestamped with the start time.

To access the file, you can either access it from runtime on the device (for example, to attach it to an email that the user sends), or if you have access to the device, you can access them via iTunes (pre-Catalina) or the MacOS Finder (post-Catalina). To access the files on the device you must make the following small modifications to your app:

MacOS Catalina or Later
  1. Add the key UIFileSharingEnabled to your info.plist. Set the value to YES.
  2. Connect the device to a MacOS computer.
  3. Open the Finder, click on the device in the sidebar, then click on "Files" > "Your App Name".
  4. You should see a folder called "smartdevicelink". Drag and drop the folder to your desktop (or somewhere in your file system). When you open the folder on your computer, you will see the log files for each session (default maxes out at 3).
MacOS Pre-Catalina
  1. Add the key UIFileSharingEnabled to your info.plist. Set the value to YES.
  2. Connect the device to a computer that has iTunes installed.
  3. Open iTunes, click on the icon for the device, then click on "File Sharing" > "Your App Name".
  4. You should see a folder called "smartdevicelink". Select the folder and click "Save". When you open the folder on your computer, you will see the log files for each session (default maxes out at 3).
File Logging and Production Releases
  1. You should remove the file sharing enabled info.plist key before submitting your app to Apple.
  2. If you are testing an archive build, you will only be able to view error and warning logs if the build configuration was set to "release". To get debug and/or verbose logs you must create the archive build with the build configuration set to "debug".

Custom Log Targets

The protocol all log targets conform to, SDLLogTarget, is public. If you wish to make a custom log target in order to, for example, log to a server, it should be fairly easy to do so. If it can be used by other developers and is not specific to your app, then submit it back to the SmartDeviceLink iOS library project! If you want to add targets in addition to the default target that will output to the console:

logConfig.targets = [logConfig.targets setByAddingObjectsFromArray:@[[SDLLogTargetFile logger]]];
let _ = logConfig.targets.insert(SDLLogTargetFile())


A module is a set of files packaged together. Create modules using the SDLLogFileModule class and add it to the configuration. Modules are used when outputting a log message. The log message may specify a module instead of a specific file name for clarity's sake. The SDL library will automatically add the modules corresponding to its own files after you submit your configuration. For your specific use case, you may wish to provide a module corresponding to your whole app's integration and simply name it with your app's name, or, you could split it up further if desired. To add modules to the configuration:

logConfig.modules = [logConfig.modules setByAddingObjectsFromArray:@[[SDLLogFileModule moduleWithName:@"Test" files:[NSSet setWithArray:@[@"File1", @"File2"]]]]];
logConfig.modules.insert(SDLLogFileModule(name: "Test", files: ["File1, File2"]))


Filters are a compile-time concept of filtering in or out specific log messages based on a variety of possible factors. Call SDLLogFilter to easily set up one of the default filters or to create your own using a custom SDLLogFilterBlock. You can filter to only allow certain files or modules to log, only allow logs with a certain string contained in the message, or use regular expressions.

SDLLogFilter *filter = [SDLLogFilter filterByDisallowingString:@"Test" caseSensitive:NO];
let filter = SDLLogFilter(byDisallowingString: "Test", caseSensitive: false)

Logging with the SDL Logger

In addition to viewing the library logs, you also have the ability to log with the SDL logger. All messages logged through the SDL logger, including your own, will use your SDLLogConfiguration settings.

Objective-C Projects

First, import the SDLLogMacros header.

#import "SDLLogMacros.h"

Then, simply use the convenient log macros to create a custom SDL log in your project.

SDLLogV(@"This is a verbose log");
SDLLogD(@"This is a debug log");
SDLLogW(@"This is a warning log");
SDLLogE(@"This is an error log");

Swift Projects

To add custom SDL logs to your Swift project you must first install a submodule called SmartDeviceLink/Swift.


If the SDL iOS library was installed using CocoaPods, simply add the submodule to the Podfile and then install by running pod install in the root directory of the project.

target '<#Your Project Name#>' do
    pod 'SmartDeviceLink', '~> <#SDL Version#>'
    pod 'SmartDeviceLink/Swift', '~> <#SDL Version#>'

Swift Package Manager

If the SDL iOS library was installed using Swift Package Manager, install the SmartDeviceLinkSwift target to your SPM installation. Then, where you want to log, import SmartDeviceLinkSwift.

Logging in Swift

Once you have access to the SmartDeviceLinkSwift enhancements, you can use the SDLLog functions in your project.

SDLLog.v("This is a verbose log")
SDLLog.d("This is a debug log")
SDLLog.w("This is a warning log")
SDLLog.e("This is an error log")
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