NR-199912: Background Instrumentation (#192)

* NR-199912: Background Instrumentation Proof of Concept

* NR-199912: Adds NRFeatureFlag_BackgroundInstrumentation to NewRelicFeatureFlags and NRMAFlags

* feat: bg instrumentation

* rename FF BackgroundInstrumentation -> BackgroundReporting

* NR-238931: Add Background attribute to events when backgrounded.

* NR-238931: Wrap up TODOs, use proper bundleID, and use cached UIApplicationState

* CR comments addressed: NR-238932

* NR-238932: wrap up a couple of TODOs.

Author: cdillard-NewRelic

Agent.xcodeproj/project.pbxproj

@@ -80,6 +80,7 @@ extern NSString *const kNRMA_Attrib_dtId;
 extern NSString *const kNRMA_Attrib_dtTraceId;
 extern NSString *const kNRMA_Attrib_name;
 extern NSString *const kNRMA_Attrib_offline;
+extern NSString *const kNRMA_Attrib_background;
 
 extern NSString *const kNRMA_Val_errorType_HTTP;
 extern NSString *const kNRMA_Val_errorType_Network;

Agent/Analytics/Constants.h

@@ -85,6 +85,7 @@
 NSString * const kNRMA_Attrib_dtTraceId         = @"trace.id";
 NSString * const kNRMA_Attrib_name              = @"name";
 NSString * const kNRMA_Attrib_offline           = @"offline";
+NSString * const kNRMA_Attrib_background        = @"background";
 
 NSString * const kNRMA_Val_errorType_HTTP       = @"HTTPError";
 NSString * const kNRMA_Val_errorType_Network    = @"NetworkFailure";

Agent/Analytics/Constants.m

@@ -6,10 +6,13 @@
 //  Copyright © 2023 New Relic. All rights reserved.
 //
 
+#import <UIKit/UIKit.h>
+
 #import "NRMAMobileEvent.h"
 #import "Constants.h"
 #import "NRMAFlags.h"
 #import "NewRelicInternalUtils.h"
+#import "NewRelicAgentInternal.h"
 
 static NSString* const kTimestampKey = @"Timestamp";
 static NSString* const kSessionElapsedTimeKey = @"SessionElapsedTime";
@@ -38,6 +41,12 @@ - (nonnull instancetype) initWithTimestamp:(NSTimeInterval)timestamp
                 }
             }
         }
+        // Handle Background attribute addition.
+        if([NRMAFlags shouldEnableBackgroundReporting]) {
+            if ([NewRelicAgentInternal sharedInstance].currentApplicationState == UIApplicationStateBackground) {
+                [self addAttribute:kNRMA_Attrib_background value:@YES];
+            }
+        }
     }
 
     return self;

Agent/Analytics/Events/NRMAMobileEvent.m

@@ -54,7 +54,7 @@
 - (void) clearLastSessionsAnalytics;
 
 - (BOOL) checkOfflineStatus;
-
+- (BOOL) checkBackgroundStatus;
 //this utilizes setSessionAttribute:value: which validates the user input 'name'.
 - (BOOL) setLastInteraction:(NSString*)name;
 

Agent/Analytics/NRMAAnalytics.h

@@ -263,7 +263,7 @@ - (BOOL) addInteractionEvent:(NSString*)name
 
         return [_eventManager addEvent:[event autorelease]];
     } else {
-        return _analyticsController->addInteractionEvent([name UTF8String], duration_secs, [self checkOfflineStatus]);
+        return _analyticsController->addInteractionEvent([name UTF8String], duration_secs, [self checkOfflineStatus], [self checkBackgroundStatus]);
     }
 }
 
@@ -504,7 +504,7 @@ - (BOOL)addNetworkRequestEvent:(NRMANetworkRequestData *)requestData
     if ([NRMAFlags shouldEnableNetworkRequestEvents]) {
         NewRelic::NetworkRequestData* networkRequestData = [requestData getNetworkRequestData];
         NewRelic::NetworkResponseData* networkResponseData = [responseData getNetworkResponseData];
-        return _analyticsController->addRequestEvent(*networkRequestData, *networkResponseData, std::move(payload), [self checkOfflineStatus]);
+        return _analyticsController->addRequestEvent(*networkRequestData, *networkResponseData, std::move(payload), [self checkOfflineStatus], [self checkBackgroundStatus]);
     }
     return NO;
 }
@@ -516,7 +516,7 @@ - (BOOL)addNetworkErrorEvent:(NRMANetworkRequestData *)requestData
         NewRelic::NetworkRequestData* networkRequestData = [requestData getNetworkRequestData];
         NewRelic::NetworkResponseData* networkResponseData = [responseData getNetworkResponseData];
 
-        return _analyticsController->addNetworkErrorEvent(*networkRequestData, *networkResponseData,std::move(payload), [self checkOfflineStatus]);
+        return _analyticsController->addNetworkErrorEvent(*networkRequestData, *networkResponseData,std::move(payload), [self checkOfflineStatus], [self checkBackgroundStatus]);
     }
 
     return NO;
@@ -529,7 +529,7 @@ - (BOOL)addHTTPErrorEvent:(NRMANetworkRequestData *)requestData
         NewRelic::NetworkRequestData* networkRequestData = [requestData getNetworkRequestData];
         NewRelic::NetworkResponseData* networkResponseData = [responseData getNetworkResponseData];
 
-        return _analyticsController->addHTTPErrorEvent(*networkRequestData, *networkResponseData, std::move(payload), [self checkOfflineStatus]);
+        return _analyticsController->addHTTPErrorEvent(*networkRequestData, *networkResponseData, std::move(payload), [self checkOfflineStatus], [self checkBackgroundStatus]);
     }
     return NO;
 }
@@ -913,6 +913,13 @@ - (BOOL) checkOfflineStatus {
     return false;
 }
 
+- (BOOL) checkBackgroundStatus {
+    if([NRMAFlags shouldEnableBackgroundReporting]) {
+        return ([NewRelicAgentInternal sharedInstance].currentApplicationState == UIApplicationStateBackground);
+    }
+    return false;
+}
+
 - (BOOL)recordUserAction:(NRMAUserAction *)userAction {
     if (userAction == nil) { return NO; };
 

Agent/Analytics/NRMAAnalytics.mm

@@ -53,6 +53,8 @@
 
 + (BOOL) shouldEnableNewEventSystem;
 
++ (BOOL) shouldEnableBackgroundReporting;
+
 + (NSArray<NSString*>*) namesForFlags:(NRMAFeatureFlags)flags;
 
 // Private Setting

Agent/FeatureFlags/NRMAFlags.h

@@ -173,6 +173,11 @@ + (BOOL) shouldEnableLogReporting {
 + (BOOL) shouldEnableNewEventSystem {
     return ([NRMAFlags featureFlags] & NRFeatureFlag_NewEventSystem) != 0;
 }
+
++ (BOOL) shouldEnableBackgroundReporting {
+    return ([NRMAFlags featureFlags] & NRFeatureFlag_BackgroundReporting) != 0;
+}
+
 + (NSArray<NSString*>*) namesForFlags:(NRMAFeatureFlags)flags {
     NSMutableArray *retArray = [NSMutableArray array];
     if ((flags & NRFeatureFlag_InteractionTracing) == NRFeatureFlag_InteractionTracing) {
@@ -234,6 +239,10 @@ + (BOOL) shouldEnableNewEventSystem {
     if ((flags & NRFeatureFlag_NewEventSystem) == NRFeatureFlag_NewEventSystem) {
         [retArray addObject:@"NewEventSystem"];
     }
+    if ((flags & NRFeatureFlag_BackgroundReporting) == NRFeatureFlag_BackgroundReporting) {
+        [retArray addObject:@"BackgroundReporting"];
+    }
+    
     return retArray;
 }
 

Agent/FeatureFlags/NRMAFlags.m

@@ -13,6 +13,8 @@
 #import "NRMAUserActionFacade.h"
 #import "NRMAURLTransformer.h"
 
+#import <BackgroundTasks/BackgroundTasks.h>
+
 // Keys used for harvester data request.
 #define NEW_RELIC_APP_VERSION_HEADER_KEY        @"X-NewRelic-App-Version"
 #define NEW_RELIC_OS_NAME_HEADER_KEY            @"X-NewRelic-OS-Name"
@@ -44,6 +46,8 @@
 
 @property (nonatomic, assign) BOOL isShutdown;
 
+@property (nonatomic, readonly, assign) UIApplicationState currentApplicationState;
+
 + (void)shutdown;
 
 + (void)startWithApplicationToken:(NSString*)appToken

Agent/General/NewRelicAgentInternal.h

@@ -149,6 +149,16 @@ - (id) initWithCollectorAddress:(NSString*)collectorHost
 
     self = [super init];
     if (self) {
+
+        // NOTE: BackgroundReporting is only enabled for iOS 13+.
+        if ([NRMAFlags shouldEnableBackgroundReporting]) {
+            if (@available(iOS 13.0, *)) {
+                [[BGTaskScheduler sharedScheduler] registerForTaskWithIdentifier:[[NSBundle mainBundle] bundleIdentifier] usingQueue:nil launchHandler:^(__kindof BGTask * _Nonnull task) {
+                    [self handleAppRefreshTask: task];
+                }];
+            }
+        }
+
         self.appWillTerminate = NO;
         [NRMACPUVitals setAppStartCPUTime];
         if ([UIApplication sharedApplication].applicationState != UIApplicationStateBackground) {
@@ -187,6 +197,10 @@ - (id) initWithCollectorAddress:(NSString*)collectorHost
                                                          name:UIApplicationWillTerminateNotification
                                                        object:[UIApplication sharedApplication]];
 
+            if ([NRMAFlags shouldEnableBackgroundReporting]) {
+                [[UIApplication sharedApplication] setMinimumBackgroundFetchInterval:UIApplicationBackgroundFetchIntervalMinimum];
+            }
+
             NRLOG_INFO(@"Agent enabled");
 
             // Store Data For Crash Reporter
@@ -532,6 +546,8 @@ - (void) applicationWillEnterForeground {
         return;
     }
 
+    _currentApplicationState = UIApplicationStateActive;
+
     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,
                                              0),
                    ^{
@@ -621,6 +637,8 @@ - (void) applicationDidEnterBackground {
     }
     // We are leaving the background.
     didFireEnterForeground = NO;
+    
+    _currentApplicationState = UIApplicationStateBackground;
 
     [[NRMAHarvestController harvestController].harvestTimer stop];
 
@@ -652,7 +670,7 @@ - (void) applicationDidEnterBackground {
     if ([[UIDevice currentDevice] respondsToSelector:@selector(isMultitaskingSupported)] &&
         [[UIDevice currentDevice] isMultitaskingSupported]) {
 
-
+        // Current One time background task is dispatched upon going to the background.
         UIApplication* application = [UIApplication sharedApplication];
 
         // Mark the start of our background task.
@@ -700,6 +718,8 @@ - (void) applicationDidEnterBackground {
                     if (self.appWillTerminate) {
                         return;
                     }
+
+                    // Currently this is where the actual harvest occurs when we go to background
                     NRLOG_VERBOSE(@"Harvesting data in background");
                     [[[NRMAHarvestController harvestController] harvester] execute];
 #ifndef  DISABLE_NRMA_EXCEPTION_WRAPPER
@@ -708,7 +728,13 @@ - (void) applicationDidEnterBackground {
                                                         class:NSStringFromClass([NRMAHarvester class])
                                                      selector:@"execute"];
                 } @finally {
-                    [self agentShutdown];
+
+                    if ([NRMAFlags shouldEnableBackgroundReporting]) {
+                        NRLOG_VERBOSE(@"used to agentShutdown. Continuing since BackgroundInstrumentation enabled.");
+                    }
+                    else {
+                         [self agentShutdown];
+                    }
                 }
 #endif
 
@@ -717,6 +743,11 @@ - (void) applicationDidEnterBackground {
                 [application endBackgroundTask:background_task];
                 // Invalidate the background_task.
                 background_task = UIBackgroundTaskInvalid;
+
+                if ([NRMAFlags shouldEnableBackgroundReporting]) {
+                    // Schedule the next background harvest.
+                    [self scheduleHeartbeatTask];
+                }
             }
         });
     } else {
@@ -750,6 +781,53 @@ - (void) agentShutdown {
     [NRMALastActivityTraceController clearLastActivityStamp];
 }
 
+// We only support background fetch in iOS 13+
+- (void) scheduleHeartbeatTask {
+    if (@available(iOS 13.0, *)) {
+        BGAppRefreshTaskRequest *request = [[BGAppRefreshTaskRequest alloc] initWithIdentifier:[[NSBundle mainBundle] bundleIdentifier]];
+        request.earliestBeginDate = nil;//[NSDate dateWithTimeIntervalSinceNow:5 * 60];
+
+        NSError *error = nil;
+
+            [[BGTaskScheduler sharedScheduler] submitTaskRequest:request error:&error];
+
+        if (error) {
+            NRLOG_ERROR(@"Error schedule heartbeat: %@", error);
+        }
+        else {
+            NRLOG_VERBOSE(@"Scheduled heartbeat");
+
+        }
+    }
+}
+
+- (void) handleAppRefreshTask:(BGAppRefreshTask *)task {
+    NRLOG_VERBOSE(@"handleAppRefreshTask BGAppRefreshTask");
+    if (@available(iOS 13.0, *)) {
+
+        // We always reschedule the heartbeat task.
+        [self scheduleHeartbeatTask];
+
+        __weak BGAppRefreshTask *weakTask = task;
+
+        [task setExpirationHandler:^{
+            __strong BGAppRefreshTask *strongTask = weakTask;
+            if (strongTask) {
+                [strongTask setTaskCompletedWithSuccess:false];
+            }
+        }];
+
+        [[[NRMAHarvestController harvestController] harvester] execute];
+
+        [task setTaskCompletedWithSuccess:true];
+    }
+    else {
+        NRLOG_VERBOSE(@"No background tasks pre iOS 13");
+
+    }
+
+}
+
 + (BOOL) harvestNow {
     return [NRMAHarvestController harvestNow];
 }

Agent/General/NewRelicAgentInternal.m

@@ -163,7 +163,7 @@ - (void) checkOffline:(std::shared_ptr<NewRelic::Hex::Report::HexReport>) report
         @synchronized(r) {
             NRMANetworkStatus status = [r currentReachabilityStatus];
             if (status == NotReachable) {
-                report->setAttributeNoValidation("offline", true);
+                report->setAttributeNoValidation(__kNRMA_Attrib_offline, true);
             }
         }
     }