Initialize health metrics and telemetry collector

Author: sarahchen6

dd-trace-core/src/main/java/datadog/trace/core/CoreTracer.java

@@ -49,6 +49,7 @@
 import datadog.trace.api.metrics.SpanMetricRegistry;
 import datadog.trace.api.naming.SpanNaming;
 import datadog.trace.api.remoteconfig.ServiceNameCollector;
+import datadog.trace.api.rum.RumInjector;
 import datadog.trace.api.sampling.PrioritySampling;
 import datadog.trace.api.scopemanager.ScopeListener;
 import datadog.trace.api.time.SystemTimeSource;
@@ -83,8 +84,10 @@
 import datadog.trace.core.datastreams.DefaultDataStreamsMonitoring;
 import datadog.trace.core.flare.TracerFlarePoller;
 import datadog.trace.core.histogram.Histograms;
+import datadog.trace.core.monitor.DefaultRumInjectorHealthMetrics;
 import datadog.trace.core.monitor.HealthMetrics;
 import datadog.trace.core.monitor.MonitoringImpl;
+import datadog.trace.core.monitor.RumInjectorHealthMetrics;
 import datadog.trace.core.monitor.TracerHealthMetrics;
 import datadog.trace.core.propagation.ExtractedContext;
 import datadog.trace.core.propagation.HttpCodec;
@@ -204,6 +207,7 @@ public static CoreTracerBuilder builder() {
   private final Monitoring performanceMonitoring;
 
   private final HealthMetrics healthMetrics;
+  private final RumInjectorHealthMetrics rumInjectorHealthMetrics;
   private final Recording traceWriteTimer;
   private final IdGenerationStrategy idGenerationStrategy;
   private final TraceCollector.Factory traceCollectorFactory;
@@ -702,6 +706,15 @@ private CoreTracer(
             ? new TracerHealthMetrics(this.statsDClient)
             : HealthMetrics.NO_OP;
     healthMetrics.start();
+
+    rumInjectorHealthMetrics =
+        config.isHealthMetricsEnabled() && config.isRumEnabled()
+            ? new DefaultRumInjectorHealthMetrics(this.statsDClient)
+            : RumInjectorHealthMetrics.NO_OP;
+    rumInjectorHealthMetrics.start();
+    // Register health metrics telemetry collector with RumInjector
+    RumInjector.setTelemetryCollector((DefaultRumInjectorHealthMetrics) rumInjectorHealthMetrics);
+
     performanceMonitoring =
         config.isPerfMetricsEnabled()
             ? new MonitoringImpl(this.statsDClient, 10, SECONDS)
@@ -1247,6 +1260,7 @@ public void close() {
     tracingConfigPoller.stop();
     pendingTraceBuffer.close();
     writer.close();
+    rumInjectorHealthMetrics.close();
     statsDClient.close();
     metricsAggregator.close();
     dataStreamsMonitoring.close();