NR-199912: Background Instrumentation

[cdillard-NewRelic]

// NOTE: BackgroundReporting is only enabled for iOS 13+.

Accomplishes Acceptance Criteria of tickets:

https://new-relic.atlassian.net/browse/NR-238932
https://new-relic.atlassian.net/browse/NR-238931

Prerequisites in your iOS app project to use Background instrumentation

Add the key Permitted background task scheduler identifiers with an array including an item containing your apps bundle Id.

Enable Background Fetch and Background Processing in the “Background Modes” section of the Xcode project capabilities.

Run test harvest in background with:

e -l objc -- (void)[[BGTaskScheduler sharedScheduler] _simulateLaunchForTaskWithIdentifier:@"com.newrelic.NRTestApp.bitcode"]

replacing com.newrelic.NRTestApp.bitcode with your apps bundleId.

Or Await the periodically occurring harvest in the background.

The exact frequency at which your tasks will run is determined by the system based on factors like device usage, batt life, and workloads. Therefore while we can request periodic execution , the system ultimately is the one that decides when to execute tasks. The background task will be run once per 24hr period.

In order to add BackgroundTasks to app you must add this to your AppDelegate.

    // Background fetch handling.
    func application(_ application: UIApplication, performFetchWithCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {

        NewRelic.logVerbose("performFetchWithCompletionHandler called")
        completionHandler(.newData)
    }

---

Adds changes to NewRelicAgentInternal such that BackgroundTasks framework is interacted with and background task can be scheduled for harvest

Comments out following files as they are no longer used in our agent project.

Agent/HandledException/NRMAHexBackgroundUploader.h
Agent/HandledException/NRMASessionIdentifierManager.h
Tests/Unit-Tests/NewRelicAgentTests/Handled-Exception-Tests/TestSessionIdentifierManger.m

[cdillard-NewRelic]

Using background tasks framework like my open Proof of Concept for iOS Background Instrumentation on iOS only guarantees that iOS will harvest in the background once per 24hr period. It’s kind of crappy but its the best guarantee we can get from iOS and background execution.