Apple Configuration Profile for Logging in iOS 10 and macOS Sierra

Extra Logging for My Great App.mobileconfig

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<!-- iOS 10, macOS Sierra, and friends bring a new logging subsystem that's
supposed to scale from the kernel, up to frameworks, and up to apps. It defaults
to a more regimented, privacy-focused approach that large apps and complex
systems need.

It, along with Activity Tracing introduced in iOS 8 and macOS Yosemite and the
Console app in macOS Sierra, hope to help you graduate from caveman debugging to
quickly identify issues across time, events, user input, and even process
boundaries.

This configuration profile template allows you to change logging behaviors
for your app, your frameworks, third party code, and even Apple code without
access to the source. The idea is to leave all your logging code in your app —
even when shipping – and change the information level at runtime.

Read more about this:
 - https://developer.apple.com/reference/os/1891852-logging
 - https://developer.apple.com/videos/play/wwdc2016/721/

You can modify and install this payload by double-clicking it in macOS, or on
an iOS-based device using Apple Configurator. You can also use Apple
Configurator to sign and send this profile to others.

This, too, is all documented:
- https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/iPhoneOTAConfiguration/Introduction/Introduction.html#//apple_ref/doc/uid/TP40009505
- https://developer.apple.com/library/ios/featuredarticles/iPhoneConfigurationProfileRef/Introduction/Introduction.html
- http://nshipster.com/configuration-profiles/

And, always remember: assume positive intent. -->
<dict>
	<!-- Change this UUID using `uuidgen`. -->
	<key>PayloadUUID</key>
	<string>00000000-0000-0000-0000-000000000000</string>
	<!-- Increment when changing the contents of ANY payload. -->
	<key>PayloadVersion</key>
	<integer>1</integer>
	<!-- Change this identifier and other info based on your credentials. -->
	<key>PayloadIdentifier</key>
	<string>com.great-company.my-great-app.logging</string>
	<key>PayloadDisplayName</key>
	<string>Extra Logging for My Great App</string>
	<key>PayloadOrganization</key>
	<string>Great Company</string>
	<!-- This message is displayed to the user during install. -->
	<key>ConsentText</key>
	<dict>
		<key>default</key>
		<string>The Extra Logging for My Great App Profile generates extra data to help us troubleshoot issues during the development process. Increased logging maay increase battery consumption or decrease performance in Great Company applications.

You will be able to turn on and off logging at any time while the Profile is installed. To turn off logging on your macOS device, open System Preferences, select rofiles," then select "Extra Logging for My Great App" and click the remove button.

This profile will automatically be removed after 30 days.</string>
	</dict>
	<!-- Configuration 'payloads' affect various parts of macOS and iOS. -->
	<key>PayloadContent</key>
	<array>
		<!-- iOS 10/macOS Sierra-style logging payload -->
		<dict>
				<!-- Increment when changing the contents. -->
				<key>PayloadVersion</key>
				<integer>1</integer>
				<!-- Change this UUID using `uuidgen`. -->
				<key>PayloadUUID</key>
				<string>00000000-0000-0000-0000-000000000000</string>
				<!-- The contents of these follow the format at:
				https://developer.apple.com/reference/os/1891852-logging#1682426 -->
				<key>Subsystems</key>
				<dict>
					<!-- A subsystem is your app's bundle ID or is explicitly
					set through the os_log_create. Wildcards are not
					accepted. These dicts may be written as <#subsystem#>.plist
					to /Library/Preferences/Logging/Subsystems/. -->
					<key>com.great-company.my-great-app</key>
					<dict>
						<key>DEFAULT-OPTIONS</key>
						<dict>
							<key>Level</key>
							<dict>
								<!-- The lowest-level log that's enabled.
								All log messages sent through NSLog are at
								the Default level.

								Accepted values:
								 - Inherit: The default. Categories inherit
								   subsystem behavior, subsystems inherit the
								   system (OS) behavior.
								 - Default: Only default-level messages.
								 - Info: Default-level and info-level messages.
								 - Debug: All messages. -->
								<key>Enable</key>
								<string>Debug</string>
								<!-- The lowest-level log that's written to
								disk.

								Accepted values:
								 - Inherit: The default. Categories inherit
								   subsystem behavior, subsystems inherit the
								   system (OS) behavior.
								 - Default: Only default-level messages.
								 - Info: Default-level and info-level messages.
								 - Debug: All messages. -->
								<key>Persist</key>
								<string>Debug</string>
							</dict>
							<!-- Changes how `%@` et. al. are formatted into
							the log.

							To ensure the privacy of users, it is recommended
							that log messages consist strictly of static strings
							and numbers.

							Accepted values:
							 - Inherit. The default. Categories inherit
							   subsystem behavior, subsystems inherit the
							   system (OS) behavior.
							 - Public: Dynamic strings and complex dynamic
							   objects are collected for the log.
							 - Private: Static strings and numbers are collected
							   for the log. -->
							<key>Default-Privacy-Setting</key>
							<string>Public</string>
							<!-- Changes how long non-critical messages stay
							in the log, in days (I think).

							Keys for this dictionary are the non-critical
							log levels: Default, Debug, and Info. -->
							<key>TTL</key>
							<dict>
								<key>Default</key>
								<integer>14</integer>
							</dict>
							<!-- If messages are attached to the activity
							tree, both in the Console app and in crash logs. -->
							<key>Propagate-with-Activity</key>
							<true/>
						</dict>
						<!-- Categories are explicitly set through
						os_log_create, and override the DEFAULT_OPTIONS
						payload. -->
						<key>CategoryName</key>
						<dict/>
						<!-- Enables large messages in the log. This WILL have
						a detrimental effect on performance. -->
						<key>Enable-Oversize-Messages</key>
						<true/>
					</dict>
				</dict>
				<!-- end of subsystem list -->
				<key>PayloadType</key>
				<string>com.apple.system.logging</string>
				<key>PayloadIdentifier</key>
				<string>LoggingPayload</string>
		</dict>
		<!-- end of logging payload -->
	</array>
	<!-- end of payload items -->
	<!-- Profile self-removes in 30 days. -->
	<key>DurationUntilRemoval</key>
	<integer>2592000</integer>
	<key>PayloadType</key>
	<string>Configuration</string>
</dict>
</plist>

tl;dr: The PayloadVersion property should not be incremented, and (as of this writing) should not be anything other than 1.

This property does not indicate the version your payload data; rather, it refers to the version of Apple's schema for that payload type to which your payload data conforms. It was intended to allow Apple to introduce multiple versions of a payload's schema, increasing robustness as software features were added or removed. From Apple's documentation:

"For example, changes to the VPN software in iOS might introduce a new payload version to support additional features"
— "Configuration Profile Reference", Apple, 2019, PDF

However, at this time, no such versioning has been performed; that is, every payload type defined by Apple has only a single schema version, which they have simply modified over time. This can be verified by evaluating the definitions found in Apple's device-management schema repository where, for each instance of the PayloadVersion property, Apple have:

1. Explicitly stated that the property's value must be 1.
2. Specified a rangelist schema attribute for the property with a single value of 1.
3. Both 1 and 2.

---

That nitpick aside, I'm incredibly thankful for this gist, as I wasn't sure how the subsystem's identifier should be included in the schema (Apple's docs aren't super helpful there).