Framework for emitting metrics data

src/app/clusters/wifi-network-diagnostics-server/wifi-network-diagnostics-server.cpp

@@ -28,6 +28,7 @@
 #include <lib/core/Optional.h>
 #include <platform/DiagnosticDataProvider.h>
 #include <tracing/macros.h>
+#include <tracing/metric_event.h>
 
 using namespace chip;
 using namespace chip::app;
@@ -163,7 +164,7 @@ CHIP_ERROR WiFiDiagosticsAttrAccess::ReadWiFiRssi(AttributeValueEncoder & aEncod
     {
         rssi.SetNonNull(value);
         ChipLogProgress(Zcl, "The current RSSI of the Node’s Wi-Fi radio in dB: %d", value);
-        MATTER_TRACE_METRIC("wifi_rssi", value);
+        MATTER_LOG_METRIC(chip::Tracing::kMetricWiFiRSSI, value);
     }
     else
     {

src/darwin/Framework/CHIP/MTRDeviceControllerDelegateBridge.mm

@@ -17,9 +17,10 @@
 
 #import "MTRDeviceControllerDelegateBridge.h"
 #import "MTRDeviceController.h"
+#import "MTRDeviceController_Internal.h"
 #import "MTRError_Internal.h"
 #import "MTRLogging_Internal.h"
-#import "MTRMetrics_Internal.h"
+#import "MTRMetricsCollector.h"
 
 MTRDeviceControllerDelegateBridge::MTRDeviceControllerDelegateBridge(void)
     : mDelegate(nil)
@@ -130,15 +131,10 @@
                     nodeID = @(nodeId);
                 }
 
+                // If the client implements the metrics delegate, prefer that over others
                 if ([strongDelegate respondsToSelector:@selector(controller:commissioningComplete:nodeID:metrics:)]) {
-                    MTRMetrics * metrics = [MTRMetrics new];
-
-                    if (nsError) {
-                        [metrics setValue:nsError forKey:MTRMetricCommissioningStatusKey];
-                    } else {
-                        auto * error = [NSError errorWithDomain:MTRErrorDomain code:0 userInfo:nil];
-                        [metrics setValue:error forKey:MTRMetricCommissioningStatusKey];
-                    }
+                    // Create a snapshot and clear for next operation
+                    MTRMetrics * metrics = [[MTRMetricsCollector sharedInstance] metricSnapshot:TRUE];
                     [strongDelegate controller:strongController commissioningComplete:nsError nodeID:nodeID metrics:metrics];
                 } else {
                     [strongDelegate controller:strongController commissioningComplete:nsError nodeID:nodeID];

src/darwin/Framework/CHIP/MTRDeviceControllerFactory.mm

@@ -39,6 +39,7 @@
 #import "MTRFabricInfo_Internal.h"
 #import "MTRFramework.h"
 #import "MTRLogging_Internal.h"
+#import "MTRMetricsCollector.h"
 #import "MTROTAProviderDelegateBridge.h"
 #import "MTROperationalBrowser.h"
 #import "MTRP256KeypairBridge.h"
@@ -349,6 +350,8 @@ - (void)cleanupStartupObjects
     }
 
     _diagnosticLogsDownloader = nil;
+
+    ShutdownMetricsCollection();
 }
 
 - (CHIP_ERROR)_initFabricTable:(FabricTable &)fabricTable
@@ -414,6 +417,10 @@ - (BOOL)startControllerFactory:(MTRDeviceControllerFactoryParams *)startupParams
         return YES;
     }
 
+    // Register any tracing backends. This has to be done before starting the event loop to run registering
+    // the tracing backend in the right queue context
+    StartupMetricsCollection();
+
     DeviceLayer::PlatformMgrImpl().StartEventLoopTask();
 
     __block CHIP_ERROR errorCode = CHIP_NO_ERROR;

src/darwin/Framework/CHIP/MTRFramework.mm

@@ -15,6 +15,7 @@
  */
 
 #import "MTRFramework.h"
+#import "MTRMetricsCollector.h"
 
 #include <dispatch/dispatch.h>
 #include <lib/support/CHIPMem.h>
@@ -34,5 +35,8 @@ void MTRFrameworkInit()
         // Suppress CHIP logging until we actually need it for redirection
         // (see MTRSetLogCallback()). Logging to os_log is always enabled.
         chip::Logging::SetLogFilter(chip::Logging::kLogCategory_None);
+
+        // Startup metrics collection and tracing framework
+        StartupMetricsCollection();
     });
 }

src/darwin/Framework/CHIP/MTRMetrics.h

@@ -21,14 +21,28 @@
 NS_ASSUME_NONNULL_BEGIN
 
 /**
- * A representation of metrics data for an operation.
+ * A representation of a collection of metrics data for an operation.
  */
 MTR_NEWLY_AVAILABLE
 @interface MTRMetrics : NSObject
 
+- (instancetype)init NS_UNAVAILABLE;
++ (instancetype)new NS_UNAVAILABLE;
+
+/**
+ * @brief Returns the names of all the metrics data items collected.
+ */
 @property (nonatomic, readonly, copy) NSArray<NSString *> * allKeys;
 
+/**
+ * @brief Returns metric object corresponding to the metric identified by its key
+ *
+ * @param [in] key Name of the metric
+ *
+ * @return An object containing the metric data, nil if key is invalid
+ */
 - (nullable id)valueForKey:(NSString *)key;
 
 @end
+
 NS_ASSUME_NONNULL_END

src/darwin/Framework/CHIP/MTRMetrics.mm

@@ -16,16 +16,24 @@
  */
 #import "MTRLogging_Internal.h"
 #import "MTRMetrics_Internal.h"
+#include <Foundation/Foundation.h>
 #import <Matter/MTRDefines.h>
+#include <Matter/MTRMetrics.h>
 
 @implementation MTRMetrics {
     NSMutableDictionary<NSString *, id> * _metricsData;
 }
 
 - (instancetype)init
+{
+    NSAssert(false, @"'init' unavailable, use initWithCapacity: instead");
+    return nil;
+}
+
+- (instancetype)initWithCapacity:(NSUInteger)numItems
 {
     if (self = [super init]) {
-        _metricsData = [NSMutableDictionary dictionary];
+        _metricsData = [NSMutableDictionary dictionaryWithCapacity:numItems];
     }
     return self;
 }

src/darwin/Framework/CHIP/MTRMetricsCollector.h

@@ -0,0 +1,59 @@
+/**
+ *
+ *    Copyright (c) 2024 Project CHIP Authors
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+#include <MTRDefines.h>
+#import <Matter/MTRMetrics.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * This function initializes any backend required to collect metrics data.
+ */
+void StartupMetricsCollection();
+
+/**
+ * This function shuts down any backend created to collect metrics data.
+ */
+void ShutdownMetricsCollection();
+
+/**
+ * A representation of metrics data for an operation.
+ */
+@interface MTRMetricsCollector : NSObject
+
+- (instancetype)init NS_UNAVAILABLE;
++ (instancetype)new NS_UNAVAILABLE;
+
+/**
+ * Return the singleton MTRMetricsCollector to vend MTRMetrics snapshots
+ */
++ (instancetype)sharedInstance;
+
+/**
+ * @brief This method creates a snapshot of the metrics collected until the current point in time
+ * and returns an object with the stats.
+ *
+ * @param [in] resetCollection Boolean that specifies whether or not to clear the stats collected after
+ *                             creating the snapshot.
+ *
+ * @return MTRMetric object representing the metric data.
+ */
+- (MTRMetrics *)metricSnapshot:(BOOL)resetCollection;
+
+@end
+
+NS_ASSUME_NONNULL_END