[ios, macos] Add Mapbox Maps SDK metrics manager. (#13997)

Added MGLSDKMetricsManager to keep track of SDK related events such as tile download times.

* [ios, macos] Add tile download performance event.

* [ios, macos] Modify the performance event format.

* [ios, macos] Add Mapbox Maps SDK events manager.

* [ios, macos] Remove events delegate.

* [ios, macos] Remove deprecated macro.

* [ios, macos] Rename MGLEventsManager to MGLMetricsManager.

* [ios, macos] Make MGLMetricsDelegate follow delegate convention.

* [ios, macos] Remove mbgl-filesource target dependency on MGLMetricsManager.

* [ios, macos] Update metrics manager documentation.

* [ios, macos] Add device metadata.

* [ios, macos] Rename MGLMetricsManager to MGLSDKMetricsManager.

6 files changed, 287 insertions, 5 deletions

diff --git a/platform/darwin/src/MGLNetworkConfiguration.m b/platform/darwin/src/MGLNetworkConfiguration.m
index 8262e7eea1..bac4d12ee5 100644
--- a/platform/darwin/src/MGLNetworkConfiguration.m
+++ b/platform/darwin/src/MGLNetworkConfiguration.m
@@ -1,19 +1,33 @@
-#import "MGLNetworkConfiguration.h"
+#import "MGLNetworkConfiguration_Private.h"
+
+static NSString * const MGLStartTime = @"start_time";
+static NSString * const MGLResourceType = @"resource_type";
+NSString * const kMGLDownloadPerformanceEvent = @"mobile.performance_trace";
 
 @interface MGLNetworkConfiguration ()
 
 @property (strong) NSURLSessionConfiguration *sessionConfig;
+@property (nonatomic, strong) NSMutableDictionary<NSString *, NSDictionary*> *events;
+@property (nonatomic, weak) id<MGLNetworkConfigurationMetricsDelegate> metricsDelegate;
 
 @end
 
 @implementation MGLNetworkConfiguration
 
+- (instancetype)init {
+    if (self = [super init]) {
+        self.sessionConfiguration = nil;
+        _events = [NSMutableDictionary dictionary];
+    }
+    
+    return self;
+}
+
 + (instancetype)sharedManager {
     static dispatch_once_t onceToken;
     static MGLNetworkConfiguration *_sharedManager;
     dispatch_once(&onceToken, ^{
         _sharedManager = [[self alloc] init];
-        _sharedManager.sessionConfiguration = nil;
     });
 
     return _sharedManager;
@@ -48,4 +62,53 @@
     return sessionConfiguration;
 }
 
+- (void)startDownloadEvent:(NSString *)urlString type:(NSString *)resourceType {
+    if (urlString && ![self.events objectForKey:urlString]) {
+        [self.events setObject:@{ MGLStartTime: [NSDate date], MGLResourceType: resourceType } forKey:urlString];
+    }
+}
+
+- (void)stopDownloadEvent:(NSString *)urlString {
+    [self sendEventForURL:urlString withAction:nil];
+}
+
+- (void)cancelDownloadEvent:(NSString *)urlString {
+    [self sendEventForURL:urlString withAction:@"cancel"];
+}
+
+- (void)sendEventForURL:(NSString *)urlString withAction:(NSString *)action
+{
+    if (urlString && [self.events objectForKey:urlString]) {
+        NSDictionary *eventAttributes = [self eventAttributesForURL:urlString withAction:action];
+        [self.metricsDelegate networkConfiguration:self didGenerateMetricEvent:eventAttributes];
+        [self.events removeObjectForKey:urlString];
+    }
+}
+
+- (NSDictionary *)eventAttributesForURL:(NSString *)urlString withAction:(NSString *)action
+{
+    NSDictionary *parameters = [self.events objectForKey:urlString];
+    NSDate *startDate = [parameters objectForKey:MGLStartTime];
+    NSDate *endDate = [NSDate date];
+    NSTimeInterval elapsedTime = [endDate timeIntervalSinceDate:startDate];
+    NSDateFormatter* iso8601Formatter = [[NSDateFormatter alloc] init];
+    iso8601Formatter.dateFormat = @"yyyy-MM-dd'T'HH:mm:ssZ";
+    NSString *createdDate = [iso8601Formatter stringFromDate:[NSDate date]];
+    
+    NSMutableArray *attributes = [NSMutableArray array];
+    [attributes addObject:@{ @"name" : @"resource" , @"value" : urlString }];
+    [attributes addObject:@{ @"name" : MGLResourceType , @"value" : [parameters objectForKey:MGLResourceType] }];
+    if (action) {
+        [attributes addObject:@{ @"name" : @"action" , @"value" : action }];
+    }
+
+    return @{
+             @"event" : kMGLDownloadPerformanceEvent,
+             @"created" : createdDate,
+             @"sessionId" : [NSUUID UUID].UUIDString,
+             @"counters" : @[ @{ @"name" : @"elapsed_time" , @"value" : @(elapsedTime) } ],
+             @"attributes" : attributes
+             };
+}
+
 @end
diff --git a/platform/darwin/src/MGLNetworkConfiguration_Private.h b/platform/darwin/src/MGLNetworkConfiguration_Private.h
new file mode 100644
index 0000000000..18c78a004a
--- /dev/null
+++ b/platform/darwin/src/MGLNetworkConfiguration_Private.h
@@ -0,0 +1,25 @@
+#import "MGLNetworkConfiguration.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@class MGLNetworkConfiguration;
+@protocol MGLNetworkConfigurationMetricsDelegate <NSObject>
+
+- (void)networkConfiguration:(MGLNetworkConfiguration *)networkConfiguration didGenerateMetricEvent:(NSDictionary *)metricEvent;
+
+@end
+
+extern NSString * const kMGLDownloadPerformanceEvent;
+
+@interface MGLNetworkConfiguration (Private)
+
+@property (nonatomic, strong) NSMutableDictionary<NSString*, NSDictionary*> *events;
+@property (nonatomic, weak) id<MGLNetworkConfigurationMetricsDelegate> metricsDelegate;
+
+- (void)startDownloadEvent:(NSString *)urlString type:(NSString *)resourceType;
+- (void)stopDownloadEvent:(NSString *)urlString;
+- (void)cancelDownloadEvent:(NSString *)urlString;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/platform/darwin/src/MGLSDKMetricsManager.h b/platform/darwin/src/MGLSDKMetricsManager.h
new file mode 100644
index 0000000000..49b3391a72
--- /dev/null
+++ b/platform/darwin/src/MGLSDKMetricsManager.h
@@ -0,0 +1,79 @@
+#import <Foundation/Foundation.h>
+#import "MGLFoundation.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ :nodoc:
+ The metrics type used to handle metrics events.
+ */
+typedef NS_ENUM(NSUInteger, MGLMetricType) {
+    /** :nodoc:
+     Metric that measures performance.
+     */
+    MGLMetricTypePerformance = 0,
+};
+
+FOUNDATION_EXTERN MGL_EXPORT NSString* MGLStringFromMetricType(MGLMetricType metricType);
+
+@class MGLMetricsManager;
+
+/**
+ :nodoc:
+ The `MGLMetricsManagerDelegate` protocol defines a set of methods that you
+ can use to receive metric events.
+ */
+@protocol MGLMetricsManagerDelegate <NSObject>
+
+/**
+ :nodoc:
+ Asks the delegate whether the metrics manager should handle metric events.
+ 
+ @param metricsManager The metrics manager object.
+ @param metricType The metric type event.
+ */
+- (BOOL)metricsManager:(MGLMetricsManager *)metricsManager shouldHandleMetric:(MGLMetricType)metricType;
+
+/**
+ :nodoc:
+ Asks the delegate to handle metric events.
+ 
+ @param metricsManager The metrics manager object.
+ @param metricType The metric type event.
+ @param attributes The metric attributes.
+ */
+- (void)metricsManager:(MGLMetricsManager *)metricsManager didCollectMetric:(MGLMetricType)metricType withAttributes:(NSDictionary *)attributes;
+
+@end
+
+/**
+ :nodoc:
+ The `MGLMetricsManager` object provides a single poin to collect SDK metrics
+ such as tile download latency.
+ */
+MGL_EXPORT
+@interface MGLMetricsManager : NSObject
+
+/**
+ :nodoc:
+ Returns the shared metrics manager object.
+ */
+@property (class, nonatomic, readonly) MGLMetricsManager *sharedManager;
+
+/**
+ :nodoc:
+ The metrics manager delegate that will recieve metric events.
+ */
+@property (nonatomic, weak) id<MGLMetricsManagerDelegate> delegate;
+
+#if TARGET_OS_IOS
+/**
+ :nodoc:
+ Sends metric events to Mapbox.
+ */
+- (void)pushMetric:(MGLMetricType)metricType withAttributes:(NSDictionary *)attributes;
+#endif
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/platform/darwin/src/MGLSDKMetricsManager.m b/platform/darwin/src/MGLSDKMetricsManager.m
new file mode 100644
index 0000000000..ed48eaf0c1
--- /dev/null
+++ b/platform/darwin/src/MGLSDKMetricsManager.m
@@ -0,0 +1,99 @@
+#import "MGLSDKMetricsManager_Private.h"
+#import "MGLNetworkConfiguration_Private.h"
+#if TARGET_OS_IOS
+#import "MGLMapboxEvents.h"
+#import <mach-o/arch.h>
+#import <sys/utsname.h>
+#import <UIKit/UIKit.h>
+#endif
+
+NSString* MGLStringFromMetricType(MGLMetricType metricType) {
+    NSString *eventName;
+    
+    switch (metricType) {
+        case MGLMetricTypePerformance:
+            eventName = kMGLDownloadPerformanceEvent;
+            break;
+    }
+    return eventName;
+}
+
+@interface MGLMetricsManager() <MGLNetworkConfigurationMetricsDelegate>
+
+@property (strong, nonatomic) NSDictionary *metadata;
+
+@end
+
+@implementation MGLMetricsManager
+
++ (instancetype)sharedManager
+{
+    static dispatch_once_t once;
+    static MGLMetricsManager *sharedConfiguration;
+    dispatch_once(&once, ^{
+        sharedConfiguration = [[self alloc] init];
+        [MGLNetworkConfiguration sharedManager].metricsDelegate = sharedConfiguration;
+#if TARGET_OS_IOS
+        UIDevice *currentDevice = [UIDevice currentDevice];
+        
+        NSString *osVersion = currentDevice.systemVersion;
+        
+        NSString *screenSize = [NSString stringWithFormat:@"%.fx%.f", [UIScreen mainScreen].bounds.size.width,
+                                [UIScreen mainScreen].bounds.size.height];
+        
+        NSLocale *currentLocale = [NSLocale currentLocale];
+        NSString *country = [currentLocale objectForKey:NSLocaleCountryCode];
+        
+        NSString *device = deviceName();
+        
+        const NXArchInfo localArchInfo = *NXGetLocalArchInfo();
+        NSString *abi = [NSString stringWithUTF8String:localArchInfo.description];
+        
+        NSString *ram = [NSString stringWithFormat:@"%llu", [NSProcessInfo processInfo].physicalMemory];
+        
+        NSString *os = currentDevice.systemName;
+        
+        sharedConfiguration.metadata = @{ @"version" : osVersion,
+                                          @"screenSize" : screenSize,
+                                          @"country" : country,
+                                          @"device" : device,
+                                          @"abi" : abi,
+                                          @"brand" : @"Apple",
+                                          @"ram" : ram,
+                                          @"os" : os
+                                          };
+#endif
+    });
+    return sharedConfiguration;
+}
+
+- (void)handleMetricsEvent:(MGLMetricType)metricType withAttributes:(NSDictionary *)attributes {
+    if ([self.delegate metricsManager:self shouldHandleMetric:metricType]) {
+        [self.delegate metricsManager:self didCollectMetric:metricType withAttributes:attributes];
+    }
+}
+
+#if TARGET_OS_IOS
+- (void)pushMetric:(MGLMetricType)metricType withAttributes:(NSDictionary *)attributes {
+    NSString *eventName = MGLStringFromMetricType(metricType);
+    NSMutableDictionary *mutableAttributes = [NSMutableDictionary dictionaryWithDictionary:attributes];
+    [mutableAttributes setObject:self.metadata forKey:@"metadata"];
+    
+    [MGLMapboxEvents pushEvent:eventName withAttributes:mutableAttributes];
+}
+
+NSString* deviceName()
+{
+    struct utsname systemInfo;
+    uname(&systemInfo);
+    
+    return [NSString stringWithCString:systemInfo.machine
+                              encoding:NSUTF8StringEncoding];
+}
+#endif
+
+- (void)networkConfiguration:(MGLNetworkConfiguration *)networkConfiguration didGenerateMetricEvent:(NSDictionary *)metricEvent {
+    [self handleMetricsEvent:MGLMetricTypePerformance withAttributes:metricEvent];
+}
+
+@end
diff --git a/platform/darwin/src/MGLSDKMetricsManager_Private.h b/platform/darwin/src/MGLSDKMetricsManager_Private.h
new file mode 100644
index 0000000000..a3cdfca794
--- /dev/null
+++ b/platform/darwin/src/MGLSDKMetricsManager_Private.h
@@ -0,0 +1,11 @@
+#import "MGLSDKMetricsManager.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface MGLMetricsManager (Private)
+
+- (void)handleMetricsEvent:(MGLMetricType)metricType withAttributes:(NSDictionary *)attributes;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/platform/darwin/src/http_file_source.mm b/platform/darwin/src/http_file_source.mm
index c3918ad62b..c26568d8bc 100644
--- a/platform/darwin/src/http_file_source.mm
+++ b/platform/darwin/src/http_file_source.mm
@@ -8,7 +8,7 @@
 
 #import <Foundation/Foundation.h>
 #import "MGLLoggingConfiguration_Private.h"
-#import "MGLNetworkConfiguration.h"
+#import "MGLNetworkConfiguration_Private.h"
 
 #include <mutex>
 #include <chrono>
@@ -215,14 +215,19 @@ std::unique_ptr<AsyncRequest> HTTPFileSource::request(const Resource& resource,
         }
 
         [req addValue:impl->userAgent forHTTPHeaderField:@"User-Agent"];
-
+        
+        if (resource.kind == mbgl::Resource::Kind::Tile) {
+            [[MGLNetworkConfiguration sharedManager] startDownloadEvent:url.relativePath type:@"tile"];
+        }
+        
         request->task = [impl->session
             dataTaskWithRequest:req
               completionHandler:^(NSData* data, NSURLResponse* res, NSError* error) {
                 if (error && [error code] == NSURLErrorCancelled) {
+                    [[MGLNetworkConfiguration sharedManager] cancelDownloadEvent:res.URL.relativePath];
                     return;
                 }
-
+                [[MGLNetworkConfiguration sharedManager] stopDownloadEvent:res.URL.relativePath];
                 Response response;
                 using Error = Response::Error;