From ba9bced8c9f9a99720951946139f7a8ca458fb6a Mon Sep 17 00:00:00 2001
From: Zach Montoya <zach.montoya@datadoghq.com>
Date: Fri, 17 Apr 2020 12:21:13 -0700
Subject: [PATCH] Enable the HttpSocketsHandler behind opt-in flag (#709)

Enable the HttpSocketsHandler integration only when `DD_HttpSocketsHandler_ENABLED=true`. Enable this in the CI test as well.
---
 .../Properties/launchSettings.json                         | 1 +
 .../Integrations/HttpMessageHandlerIntegration.cs          | 7 ++++++-
 src/Datadog.Trace/Configuration/TracerSettings.cs          | 6 ++++++
 .../HttpClientTests.cs                                     | 1 +
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/samples/Samples.HttpMessageHandler/Properties/launchSettings.json b/samples/Samples.HttpMessageHandler/Properties/launchSettings.json
index cfeb72c36225..6bd9bb8f6395 100644
--- a/samples/Samples.HttpMessageHandler/Properties/launchSettings.json
+++ b/samples/Samples.HttpMessageHandler/Properties/launchSettings.json
@@ -12,6 +12,7 @@
         "CORECLR_PROFILER": "{846F5F1C-F9AE-4B07-969E-05C26BC060D8}",
         "CORECLR_PROFILER_PATH": "$(ProjectDir)$(OutputPath)profiler-lib\\Datadog.Trace.ClrProfiler.Native.dll",
 
+        "DD_HttpSocketsHandler_ENABLED": "true",
         "DD_DOTNET_TRACER_HOME": "$(ProjectDir)$(OutputPath)profiler-lib",
         "DD_INTEGRATIONS": "$(ProjectDir)$(OutputPath)profiler-lib\\integrations.json"
       },
diff --git a/src/Datadog.Trace.ClrProfiler.Managed/Integrations/HttpMessageHandlerIntegration.cs b/src/Datadog.Trace.ClrProfiler.Managed/Integrations/HttpMessageHandlerIntegration.cs
index 3ef5ecd3ed4b..6f355b74aae7 100644
--- a/src/Datadog.Trace.ClrProfiler.Managed/Integrations/HttpMessageHandlerIntegration.cs
+++ b/src/Datadog.Trace.ClrProfiler.Managed/Integrations/HttpMessageHandlerIntegration.cs
@@ -169,7 +169,7 @@ private static async Task<HttpResponseMessage> SendAsyncInternal(
             HttpRequestMessage request,
             CancellationToken cancellationToken)
         {
-            if (!(handler is HttpClientHandler || reportedType.FullName.Equals("System.Net.Http.SocketsHttpHandler", StringComparison.OrdinalIgnoreCase)) ||
+            if (!(handler is HttpClientHandler || IsSocketsHttpHandlerEnabled(reportedType)) ||
                 !IsTracingEnabled(request))
             {
                 // skip instrumentation
@@ -205,6 +205,11 @@ private static async Task<HttpResponseMessage> SendAsyncInternal(
             }
         }
 
+        private static bool IsSocketsHttpHandlerEnabled(Type reportedType)
+        {
+            return Tracer.Instance.Settings.IsOptInIntegrationEnabled("HttpSocketsHandler") && reportedType.FullName.Equals("System.Net.Http.SocketsHttpHandler", StringComparison.OrdinalIgnoreCase);
+        }
+
         private static bool IsTracingEnabled(HttpRequestMessage request)
         {
             if (request.Headers.TryGetValues(HttpHeaderNames.TracingEnabled, out var headerValues))
diff --git a/src/Datadog.Trace/Configuration/TracerSettings.cs b/src/Datadog.Trace/Configuration/TracerSettings.cs
index c2cfdc57be17..9780801255cc 100644
--- a/src/Datadog.Trace/Configuration/TracerSettings.cs
+++ b/src/Datadog.Trace/Configuration/TracerSettings.cs
@@ -248,6 +248,12 @@ internal bool IsIntegrationEnabled(string name)
             return TraceEnabled && !disabled;
         }
 
+        internal bool IsOptInIntegrationEnabled(string name)
+        {
+            bool disabled = Integrations[name].Enabled != true || DisabledIntegrationNames.Contains(name);
+            return TraceEnabled && !disabled;
+        }
+
         internal double? GetIntegrationAnalyticsSampleRate(string name, bool enabledWithGlobalSetting)
         {
             var integrationSettings = Integrations[name];
diff --git a/test/Datadog.Trace.ClrProfiler.IntegrationTests/HttpClientTests.cs b/test/Datadog.Trace.ClrProfiler.IntegrationTests/HttpClientTests.cs
index a0bc982ca41b..5afc26984ea9 100644
--- a/test/Datadog.Trace.ClrProfiler.IntegrationTests/HttpClientTests.cs
+++ b/test/Datadog.Trace.ClrProfiler.IntegrationTests/HttpClientTests.cs
@@ -16,6 +16,7 @@ public HttpClientTests(ITestOutputHelper output)
             : base("HttpMessageHandler", output)
         {
             SetEnvironmentVariable("DD_TRACE_DOMAIN_NEUTRAL_INSTRUMENTATION", "true");
+            SetEnvironmentVariable("DD_HttpSocketsHandler_ENABLED", "true");
         }
 
         [Fact]