chore: Merge span-bridge feature branch (#3136)

Author: tippmar-nr

.github/copilot-instructions.md

@@ -2,5 +2,8 @@
 - Use the latest C# language version available in the project.
 - Ensure all files include the standard license header at the top.
 - When writing unit tests, always use modern NUnit assertions.
-- We use JustMock.Lite, so use only mock configurations that are valid for that package.
+- We use the free version of JustMock (JustMock Lite), so use only mock configurations that are valid for that package.
 - Always include the required usings at the top of the file.
+- Do not use reflection in unit tests to access private members of the class under test.
+- Always add [Teardown] attributes to the test class and test methods, respectively, when the test class uses disposable resources in the [Setup] method.
+- When refactoring code, preserve existing comments and documentation.

src/Agent/NewRelic/Agent/Core/Agent.cs

@@ -32,6 +32,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using NewRelic.Agent.Core.DataTransport;
+using NewRelic.Agent.Core.OpenTelemetryBridge;
 
 namespace NewRelic.Agent.Core
 {
@@ -67,6 +68,7 @@ public class Agent : IAgent // any changes to api, update the interface in exten
         private readonly ISimpleSchedulingService _simpleSchedulingService;
 
         private readonly ICustomEventTransformer _customEventTransformer;
+        private readonly NewRelicActivitySourceProxy _activitySourceProxy;
 
         public Agent(ITransactionService transactionService, ITransactionTransformer transactionTransformer,
             IThreadPoolStatic threadPoolStatic, ITransactionMetricNameMaker transactionMetricNameMaker, IPathHashMaker pathHashMaker,
@@ -76,7 +78,7 @@ public Agent(ITransactionService transactionService, ITransactionTransformer tra
             IConfigurationService configurationService, IAgentHealthReporter agentHealthReporter, IAgentTimerService agentTimerService,
             IMetricNameService metricNameService, Api.ITraceMetadataFactory traceMetadataFactory, ICATSupportabilityMetricCounters catMetricCounters,
             ILogEventAggregator logEventAggregator, ILogContextDataFilter logContextDataFilter, ISimpleSchedulingService simpleSchedulingService,
-            ICustomEventTransformer customEventTransformer)
+            ICustomEventTransformer customEventTransformer, NewRelicActivitySourceProxy activitySourceProxy)
         {
             _transactionService = transactionService;
             _transactionTransformer = transactionTransformer;
@@ -101,6 +103,8 @@ public Agent(ITransactionService transactionService, ITransactionTransformer tra
 
             _customEventTransformer = customEventTransformer;
 
+            _activitySourceProxy = activitySourceProxy;
+
             Instance = this;
         }
 
@@ -595,6 +599,8 @@ public void RecordLogMessage(string frameworkName, object logEvent, Func<object,
             }
         }
 
+        public NewRelicActivitySourceProxy ActivitySourceProxy => _activitySourceProxy;
+
         #endregion
 
         #region Helpers

src/Agent/NewRelic/Agent/Core/AgentManager.cs

@@ -159,6 +159,9 @@ private AgentManager()
             // Start the AgentHealthReporter early so that we can potentially report health issues during startup
             _agentHealthReporter = _container.Resolve<IAgentHealthReporter>();
 
+            if (Configuration.OpenTelemetryBridgeEnabled)
+                _container.Resolve<OpenTelemetryBridge.ActivityBridge>().Start();
+
             // Attempt to auto start the agent once all services have resolved, except in serverless mode
             if (!bootstrapConfig.ServerlessModeEnabled)
                 _container.Resolve<IConnectionManager>().AttemptAutoStart();

src/Agent/NewRelic/Agent/Core/Configuration/DefaultConfiguration.cs

@@ -3108,6 +3108,56 @@ public string AwsAccountId
         }
         #endregion
 
+        #region Otel Bridge
+
+        private static readonly string[] DefaultIncludedActivitySources = ["NewRelic.Agent"];
+
+        private List<string> _includedActivitySources;
+        public List<string> IncludedActivitySources
+        {
+            get
+            {
+                if (_includedActivitySources == null)
+                {
+                    var includedActivitySources = DefaultIncludedActivitySources.ToList();
+
+                    var appSetting = TryGetAppSettingAsString("OpenTelemetry.ActivitySource.Include");
+                    if (!string.IsNullOrEmpty(appSetting))
+                    {
+                        includedActivitySources.AddRange(appSetting.Split(','));
+                    }
+
+                    _includedActivitySources = includedActivitySources;
+                }
+
+                return _includedActivitySources;
+            }
+        }
+
+        private List<string> _excludedActivitySources;
+        public List<string> ExcludedActivitySources
+        {
+            get
+            {
+                if (_excludedActivitySources == null)
+                {
+                    _excludedActivitySources = new List<string>();
+
+                    var appSetting = TryGetAppSettingAsString("OpenTelemetry.ActivitySource.Exclude");
+                    if (!string.IsNullOrEmpty(appSetting))
+                    {
+                        _excludedActivitySources.AddRange(appSetting.Split(','));
+                    }
+                }
+
+                return _excludedActivitySources;
+            }
+        }
+
+        public bool OpenTelemetryBridgeEnabled => EnvironmentOverrides(TryGetAppSettingAsBoolWithDefault("OpenTelemetry.Enabled", false), "NEW_RELIC_OPEN_TELEMETRY_BRIDGE_ENABLED");
+
+        #endregion
+
         public static bool GetLoggingEnabledValue(IEnvironment environment, configurationLog localLogConfiguration)
         {
             return EnvironmentOverrides(environment, localLogConfiguration.enabled, "NEW_RELIC_LOG_ENABLED");

src/Agent/NewRelic/Agent/Core/Configuration/ReportedConfiguration.cs

@@ -746,6 +746,15 @@ public IReadOnlyDictionary<string, string> GetAppSettings()
         public bool AwsLambdaApmModeEnabled => _configuration.AwsLambdaApmModeEnabled;
 
 
+        [JsonProperty("otel_bridge.included_activity_sources")]
+        public List<string> IncludedActivitySources => _configuration.IncludedActivitySources;
+
+        [JsonProperty("otel_bridge.excluded_activity_sources")]
+        public List<string> ExcludedActivitySources => _configuration.ExcludedActivitySources;
+
+        [JsonProperty("otel_bridge.enabled")]
+        public bool OpenTelemetryBridgeEnabled => _configuration.OpenTelemetryBridgeEnabled;
+
         #endregion
     }
 }

src/Agent/NewRelic/Agent/Core/DependencyInjection/AgentServices.cs

@@ -45,6 +45,7 @@
 using NewRelic.Agent.Extensions.Providers.Wrapper;
 using NewRelic.Agent.Core.SharedInterfaces.Web;
 using NewRelic.Agent.Core.Labels;
+using NewRelic.Agent.Core.OpenTelemetryBridge;
 
 namespace NewRelic.Agent.Core.DependencyInjection
 {
@@ -233,6 +234,9 @@ public static void RegisterServices(IContainer container, bool serverlessModeEna
 
             container.Register<UpdatedLoadedModulesService, UpdatedLoadedModulesService>();
 
+            container.Register<ActivityBridge, ActivityBridge>();
+            container.Register<NewRelicActivitySourceProxy, NewRelicActivitySourceProxy>();
+
             container.Build();
         }
 

src/Agent/NewRelic/Agent/Core/DistributedTracing/DistributedTracePayloadHandler.cs

@@ -31,6 +31,8 @@ public interface IDistributedTracePayloadHandler
         ITracingState AcceptDistributedTraceHeaders<T>(T carrier, Func<T, string, IEnumerable<string>> getter, TransportType transportType, DateTime transactionStartTime);
 
         void InsertDistributedTraceHeaders<T>(IInternalTransaction transaction, T carrier, Action<T, string, string> setter);
+
+        void GetTraceFlagsAndState(IInternalTransaction transaction, out bool sampled, out string traceStateString);
     }
 
     public class DistributedTracePayloadHandler : IDistributedTracePayloadHandler
@@ -152,23 +154,40 @@ private string FormatTraceId(string traceId)
 
         private string BuildTracestate(IInternalTransaction transaction, DateTime timestamp)
         {
-            var accountKey = _configurationService.Configuration.TrustedAccountKey;
-            var version = 0;
-            var parentType = ParentType;
-            var parentAccountId = _configurationService.Configuration.AccountId;
-            var appId = _configurationService.Configuration.PrimaryApplicationId;
-            var spanId = _configurationService.Configuration.SpanEventsEnabled ? transaction.CurrentSegment.SpanId : string.Empty;
-            var transactionId = _configurationService.Configuration.TransactionEventsEnabled ? transaction.Guid : string.Empty;
+            // Cache configuration values to avoid repeated property access
+            var config = _configurationService.Configuration;
+            var accountKey = config.TrustedAccountKey;
+            var parentAccountId = config.AccountId;
+            var appId = config.PrimaryApplicationId;
+            var spanEventsEnabled = config.SpanEventsEnabled;
+            var transactionEventsEnabled = config.TransactionEventsEnabled;
+
+            var spanId = spanEventsEnabled ? transaction.CurrentSegment.SpanId : string.Empty;
+            var transactionId = transactionEventsEnabled ? transaction.Guid : string.Empty;
             var sampled = transaction.Sampled.Value ? "1" : "0";
-            var priority = string.Format(System.Globalization.CultureInfo.InvariantCulture, PriorityFormat, transaction.Priority);
+            var priority = transaction.Priority.ToString("0.######", System.Globalization.CultureInfo.InvariantCulture);
             var timestampInMillis = timestamp.ToUnixTimeMilliseconds();
 
-            var newRelicTracestate = $"{accountKey}@nr={version}-{parentType}-{parentAccountId}-{appId}-{spanId}-{transactionId}-{sampled}-{priority}-{timestampInMillis}";
-            var otherVendorTracestates = string.Empty;
-
-            if (transaction.TracingState?.VendorStateEntries != null && transaction.TracingState.VendorStateEntries.Any())
+            // Use StringBuilder to avoid intermediate string allocations
+            var sb = new System.Text.StringBuilder(128);
+            sb.Append(accountKey)
+                .Append("@nr=0-")
+                .Append(ParentType).Append('-')
+                .Append(parentAccountId).Append('-')
+                .Append(appId).Append('-')
+                .Append(spanId).Append('-')
+                .Append(transactionId).Append('-')
+                .Append(sampled).Append('-')
+                .Append(priority).Append('-')
+                .Append(timestampInMillis);
+
+            var newRelicTracestate = sb.ToString();
+
+            var otherVendorTracestates = String.Empty;
+            var vendorEntries = transaction.TracingState?.VendorStateEntries;
+            if (vendorEntries != null && vendorEntries.Any())
             {
-                otherVendorTracestates = string.Join(",", transaction.TracingState.VendorStateEntries);
+                otherVendorTracestates = string.Join(",", vendorEntries);
             }
 
             // If otherVendorTracestates is null/empty we get a trailing comma.
@@ -177,7 +196,8 @@ private string BuildTracestate(IInternalTransaction transaction, DateTime timest
                 return newRelicTracestate;
             }
 
-            return string.Join(",", newRelicTracestate, otherVendorTracestates);
+            // Use string.Join only if there are vendor entries
+            return string.Concat(newRelicTracestate, ",", otherVendorTracestates);
         }
 
         public IDistributedTracePayload TryGetOutboundDistributedTraceApiModel(IInternalTransaction transaction, ISegment segment = null)
@@ -250,6 +270,13 @@ private IDistributedTracePayload TryGetOutboundDistributedTraceApiModelInternal(
             return new DistributedTraceApiModel(encodedPayload);
         }
 
+        public void GetTraceFlagsAndState(IInternalTransaction transaction, out bool sampled, out string traceStateString)
+        {
+            transaction.SetSampled(_adaptiveSampler);
+            traceStateString = BuildTracestate(transaction, DateTime.UtcNow);
+            sampled = transaction.Sampled.Value;
+        }
+
         #endregion Outgoing/Create
 
         #region Incoming/Accept