Support metrics collection. (#187) (#188)

lukhnos · web-flow · commit c879a387e0ca · 2020-03-25T10:21:39.000-07:00
This adds support to handle the
`-URLSession:task:didFinishCollectingMetrics:` delegate method in the
`NSURLSessionTaskDelegate protocol`. A new callback block type,
`GTMSessionFetcherMetricsCollectionBlock`, is also added.

This feature is enabled when compiled for iOS 10+, macOS 10.12+, Mac
Catalyst 13.0+, tvOS 10.0+, or watchOS 3.0+.
diff --git a/Source/GTMSessionFetcher.h b/Source/GTMSessionFetcher.h
@@ -560,6 +560,9 @@ typedef void (^GTMSessionFetcherRetryBlock)(BOOL suggestedWillRetry,
                                             NSError * GTM_NULLABLE_TYPE error,
                                             GTMSessionFetcherRetryResponse response);
 
+API_AVAILABLE(ios(10.0), macosx(10.12), tvos(10.0), watchos(3.0))
+typedef void (^GTMSessionFetcherMetricsCollectionBlock)(NSURLSessionTaskMetrics *metrics);
+
 typedef void (^GTMSessionFetcherTestResponse)(NSHTTPURLResponse * GTM_NULLABLE_TYPE response,
                                               NSData * GTM_NULLABLE_TYPE data,
                                               NSError * GTM_NULLABLE_TYPE error);
@@ -996,6 +999,13 @@ NSData * GTM_NULLABLE_TYPE GTMDataFromInputStream(NSInputStream *inputStream, NS
 // See comments at the top of this file.
 @property(atomic, copy, GTM_NULLABLE) GTMSessionFetcherRetryBlock retryBlock;
 
+// The optional block for collecting the metrics of the present session.
+//
+// This is called on the callback queue.
+@property(atomic, copy, GTM_NULLABLE)
+    GTMSessionFetcherMetricsCollectionBlock metricsCollectionBlock API_AVAILABLE(
+        ios(10.0), macosx(10.12), tvos(10.0), watchos(3.0));
+
 // Retry intervals must be strictly less than maxRetryInterval, else
 // they will be limited to maxRetryInterval and no further retries will
 // be attempted.  Setting maxRetryInterval to 0.0 will reset it to the
diff --git a/Source/GTMSessionFetcher.m b/Source/GTMSessionFetcher.m
@@ -1795,6 +1795,9 @@ - (void)releaseCallbacks {
   self.retryBlock = nil;
   self.testBlock = nil;
   self.resumeDataBlock = nil;
+  if (@available(iOS 10.0, macOS 10.12, tvOS 10.0, watchOS 3.0, *)) {
+    self.metricsCollectionBlock = nil;
+  }
 }
 
 - (void)forgetSessionIdentifierForFetcher {
@@ -2853,6 +2856,21 @@ - (void)URLSession:(NSURLSession *)session
   }];
 }
 
+- (void)URLSession:(NSURLSession *)session
+                          task:(NSURLSessionTask *)task
+    didFinishCollectingMetrics:(NSURLSessionTaskMetrics *)metrics
+    API_AVAILABLE(ios(10.0), macosx(10.12), tvos(10.0), watchos(3.0)) {
+  @synchronized(self) {
+    GTMSessionMonitorSynchronized(self);
+    GTMSessionFetcherMetricsCollectionBlock metricsCollectionBlock = _metricsCollectionBlock;
+    if (metricsCollectionBlock) {
+      [self invokeOnCallbackQueueUnlessStopped:^{
+        metricsCollectionBlock(metrics);
+      }];
+    }
+  }
+}
+
 #if TARGET_OS_IPHONE
 - (void)URLSessionDidFinishEventsForBackgroundURLSession:(NSURLSession *)session {
   GTM_LOG_SESSION_DELEGATE(@"%@ %p URLSessionDidFinishEventsForBackgroundURLSession:%@",
@@ -3462,6 +3480,7 @@ + (GTM_NULLABLE GTMSessionFetcherSystemCompletionHandler)systemCompletionHandler
             sendProgressBlock = _sendProgressBlock,
             willCacheURLResponseBlock = _willCacheURLResponseBlock,
             retryBlock = _retryBlock,
+            metricsCollectionBlock = _metricsCollectionBlock,
             retryFactor = _retryFactor,
             allowedInsecureSchemes = _allowedInsecureSchemes,
             allowLocalhostRequest = _allowLocalhostRequest,
diff --git a/Source/GTMSessionFetcherService.h b/Source/GTMSessionFetcherService.h
@@ -63,6 +63,9 @@ extern NSString *const kGTMSessionFetcherServiceSessionKey;
 @property(atomic, assign) NSTimeInterval maxRetryInterval;
 @property(atomic, assign) NSTimeInterval minRetryInterval;
 @property(atomic, copy, GTM_NULLABLE) GTM_NSDictionaryOf(NSString *, id) *properties;
+@property(atomic, copy, GTM_NULLABLE)
+    GTMSessionFetcherMetricsCollectionBlock metricsCollectionBlock API_AVAILABLE(
+        ios(10.0), macosx(10.12), tvos(10.0), watchos(3.0));
 
 #if GTM_BACKGROUND_TASK_FETCHING
 @property(atomic, assign) BOOL skipBackgroundTask;
diff --git a/Source/GTMSessionFetcherService.m b/Source/GTMSessionFetcherService.m
@@ -121,6 +121,7 @@ @implementation GTMSessionFetcherService {
             retryBlock = _retryBlock,
             maxRetryInterval = _maxRetryInterval,
             minRetryInterval = _minRetryInterval,
+            metricsCollectionBlock = _metricsCollectionBlock,
             properties = _properties,
             unusedSessionTimeout = _unusedSessionTimeout,
             testBlock = _testBlock;
@@ -186,6 +187,9 @@ - (id)fetcherWithRequest:(NSURLRequest *)request
   fetcher.retryBlock = self.retryBlock;
   fetcher.maxRetryInterval = self.maxRetryInterval;
   fetcher.minRetryInterval = self.minRetryInterval;
+  if (@available(iOS 10.0, macOS 10.12, tvOS 10.0, watchOS 3.0, *)) {
+    fetcher.metricsCollectionBlock = self.metricsCollectionBlock;
+  }
   fetcher.properties = self.properties;
   fetcher.service = self;
   if (self.cookieStorageMethod >= 0) {
@@ -1281,6 +1285,14 @@ - (void)URLSession:(NSURLSession *)session
  didCompleteWithError:error];
 }
 
+- (void)URLSession:(NSURLSession *)session
+                          task:(NSURLSessionTask *)task
+    didFinishCollectingMetrics:(NSURLSessionTaskMetrics *)metrics
+    API_AVAILABLE(ios(10.0), macosx(10.12), tvos(10.0), watchos(3.0)) {
+  id<NSURLSessionTaskDelegate> fetcher = [self fetcherForTask:task];
+  [fetcher URLSession:session task:task didFinishCollectingMetrics:metrics];
+}
+
 // NSURLSessionDataDelegate protocol methods.
 
 - (void)URLSession:(NSURLSession *)session
diff --git a/Source/UnitTests/GTMSessionFetcherFetchingTest.m b/Source/UnitTests/GTMSessionFetcherFetchingTest.m
@@ -194,6 +194,9 @@ - (void)assertCallbacksReleasedForFetcher:(GTMSessionFetcher *)fetcher {
   XCTAssertNil(fetcher.downloadProgressBlock);
   XCTAssertNil(fetcher.willCacheURLResponseBlock);
   XCTAssertNil(fetcher.retryBlock);
+  if (@available(iOS 10.0, macOS 10.12, tvOS 10.0, watchOS 3.0, *)) {
+    XCTAssertNil(fetcher.metricsCollectionBlock);
+  }
   XCTAssertNil(fetcher.testBlock);
 
   if ([fetcher isKindOfClass:[GTMSessionUploadFetcher class]]) {
@@ -1849,6 +1852,120 @@ - (void)testInsecureRequests_WithoutFetcherService {
   [self testInsecureRequests];
 }
 
+- (void)testCollectingMetrics_WithSuccessfulFetch API_AVAILABLE(ios(10.0), macosx(10.12),
+                                                                tvos(10.0), watchos(3.0)) {
+  if (!_isServerRunning) return;
+
+  NSString *localURLString = [self localURLStringToTestFileName:kGTMGettysburgFileName];
+  GTMSessionFetcher *fetcher = [self fetcherWithURLString:localURLString];
+  __block NSURLSessionTaskMetrics *collectedMetrics = nil;
+
+  fetcher.metricsCollectionBlock = ^(NSURLSessionTaskMetrics *_Nonnull metrics) {
+    collectedMetrics = metrics;
+  };
+
+  [fetcher beginFetchWithCompletionHandler:^(NSData *data, NSError *error) {
+    [self assertSuccessfulGettysburgFetchWithFetcher:fetcher data:data error:error];
+  }];
+  XCTAssertTrue([fetcher waitForCompletionWithTimeout:_timeoutInterval], @"timed out");
+  [self assertCallbacksReleasedForFetcher:fetcher];
+
+  XCTAssertNotNil(collectedMetrics);
+  XCTAssertEqual(collectedMetrics.transactionMetrics.count, 1);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].fetchStartDate);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].connectStartDate);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].connectEndDate);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].requestStartDate);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].requestEndDate);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].responseStartDate);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].responseEndDate);
+}
+
+- (void)testCollectingMetrics_WithSuccessfulFetch_WithoutFetcherService API_AVAILABLE(
+    ios(10.0), macosx(10.12), tvos(10.0), watchos(3.0)) {
+  _fetcherService = nil;
+  [self testCollectingMetrics_WithSuccessfulFetch];
+}
+
+- (void)testCollectingMetrics_WithWrongFetch_FaildToConnect API_AVAILABLE(ios(10.0), macosx(10.12),
+                                                                          tvos(10.0),
+                                                                          watchos(3.0)) {
+  if (!_isServerRunning) return;
+
+  // Fetch a live, invalid URL
+  NSString *badURLString = @"http://localhost:86/";
+
+  GTMSessionFetcher *fetcher = [self fetcherWithURLString:badURLString];
+
+  __block NSURLSessionTaskMetrics *collectedMetrics = nil;
+  fetcher.metricsCollectionBlock = ^(NSURLSessionTaskMetrics *_Nonnull metrics) {
+    collectedMetrics = metrics;
+  };
+
+  [fetcher beginFetchWithCompletionHandler:^(NSData *data, NSError *error) {
+    XCTAssertNotNil(error);
+  }];
+  XCTAssertTrue([fetcher waitForCompletionWithTimeout:_timeoutInterval], @"timed out");
+  [self assertCallbacksReleasedForFetcher:fetcher];
+
+  XCTAssertNotNil(collectedMetrics);
+  XCTAssertEqual(collectedMetrics.transactionMetrics.count, 1);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].fetchStartDate);
+
+  // Connetion not established, and therefore the following metrics do not exist.
+  XCTAssertNil(collectedMetrics.transactionMetrics[0].connectStartDate);
+  XCTAssertNil(collectedMetrics.transactionMetrics[0].connectEndDate);
+  XCTAssertNil(collectedMetrics.transactionMetrics[0].requestStartDate);
+  XCTAssertNil(collectedMetrics.transactionMetrics[0].requestEndDate);
+  XCTAssertNil(collectedMetrics.transactionMetrics[0].responseStartDate);
+  XCTAssertNil(collectedMetrics.transactionMetrics[0].responseEndDate);
+}
+
+- (void)testCollectingMetrics_WithWrongFetch_FaildToConnect_WithoutFetcherService API_AVAILABLE(
+    ios(10.0), macosx(10.12), tvos(10.0), watchos(3.0)) {
+  _fetcherService = nil;
+  [self testCollectingMetrics_WithWrongFetch_FaildToConnect];
+}
+
+- (void)testCollectingMetrics_WithWrongFetch_BadStatusCode API_AVAILABLE(ios(10.0), macosx(10.12),
+                                                                         tvos(10.0), watchos(3.0)) {
+  if (!_isServerRunning) return;
+
+  NSString *statusURLString = [self localURLStringToTestFileName:kGTMGettysburgFileName
+                                                      parameters:@{@"status" : @"400"}];
+
+  GTMSessionFetcher *fetcher = [self fetcherWithURLString:statusURLString];
+
+  __block NSURLSessionTaskMetrics *collectedMetrics = nil;
+  fetcher.metricsCollectionBlock = ^(NSURLSessionTaskMetrics *_Nonnull metrics) {
+    collectedMetrics = metrics;
+  };
+
+  [fetcher beginFetchWithCompletionHandler:^(NSData *data, NSError *error) {
+    XCTAssertNotNil(error);
+  }];
+  XCTAssertTrue([fetcher waitForCompletionWithTimeout:_timeoutInterval], @"timed out");
+  [self assertCallbacksReleasedForFetcher:fetcher];
+
+  XCTAssertNotNil(collectedMetrics);
+  XCTAssertEqual(collectedMetrics.transactionMetrics.count, 1);
+
+  // A 400 HTTP response is still a complete response, and therefore these metrics exist.
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].fetchStartDate);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].connectStartDate);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].connectEndDate);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].requestStartDate);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].requestEndDate);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].responseStartDate);
+  XCTAssertNotNil(collectedMetrics.transactionMetrics[0].responseEndDate);
+}
+
+- (void)testCollectingMetrics_WithWrongFetch_BadStatusCode_WithoutFetcherService API_AVAILABLE(
+    ios(10.0), macosx(10.12), tvos(10.0), watchos(3.0)) {
+  _fetcherService = nil;
+  [self testCollectingMetrics_WithWrongFetch_BadStatusCode];
+}
+
 #pragma mark - TestBlock Tests
 
 - (void)testFetcherTestBlock {
diff --git a/Source/UnitTests/GTMSessionFetcherServiceTest.m b/Source/UnitTests/GTMSessionFetcherServiceTest.m
@@ -820,4 +820,29 @@ - (void)testDelegateDispatcherForFetcher {
   [session invalidateAndCancel];
 }
 
+- (void)testFetcherUsingMetricsCollectionBlockFromFetcherService API_AVAILABLE(ios(10.0),
+                                                                               macosx(10.12),
+                                                                               tvos(10.0),
+                                                                               watchos(3.0)) {
+  if (!_isServerRunning) return;
+
+  __block NSURLSessionTaskMetrics *collectedMetrics = nil;
+
+  GTMSessionFetcherService *service = [[GTMSessionFetcherService alloc] init];
+  service.metricsCollectionBlock = ^(NSURLSessionTaskMetrics *_Nonnull metrics) {
+    collectedMetrics = metrics;
+  };
+
+  NSURL *fetchURL = [_testServer localURLForFile:kValidFileName];
+  GTMSessionFetcher *fetcher = [service fetcherWithURL:fetchURL];
+  [fetcher beginFetchWithCompletionHandler:^(NSData *fetchData, NSError *fetchError) {
+    XCTAssertNotNil(fetchData);
+    XCTAssertNil(fetchError);
+  }];
+
+  [service waitForCompletionOfAllFetchersWithTimeout:10];
+
+  XCTAssertNotNil(collectedMetrics);
+}
+
 @end
