From d5126d75e147450dc44a0488361984c54901068e Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Fri, 18 Oct 2019 15:07:31 -0700
Subject: [PATCH 01/13] [WIP] Add DD_TRACE_GLOBAL_TAGS env variable and APIs
 for adding global tags

---
 .../Configuration/ConfigurationKeys.cs        |  5 ++++
 .../Configuration/JsonConfigurationSource.cs  | 18 ++++++++++++
 .../Configuration/TracerSettings.cs           | 23 +++++++++++++++
 src/Datadog.Trace/Datadog.Trace.csproj        |  1 +
 src/Datadog.Trace/Span.cs                     | 10 +++++++
 src/Datadog.Trace/Tracer.cs                   | 28 +++++++++++++++++++
 .../Configuration/ConfigurationSourceTests.cs |  3 ++
 .../Datadog.Trace.Tests.csproj                |  4 +++
 test/Datadog.Trace.Tests/TracerTests.cs       | 13 +++++++++
 9 files changed, 105 insertions(+)

diff --git a/src/Datadog.Trace/Configuration/ConfigurationKeys.cs b/src/Datadog.Trace/Configuration/ConfigurationKeys.cs
index 3c7688d7bff2..57e1e63d1e9e 100644
--- a/src/Datadog.Trace/Configuration/ConfigurationKeys.cs
+++ b/src/Datadog.Trace/Configuration/ConfigurationKeys.cs
@@ -77,6 +77,11 @@ public static class ConfigurationKeys
         /// <seealso cref="TracerSettings.AnalyticsEnabled"/>
         public const string GlobalAnalyticsEnabled = "DD_TRACE_ANALYTICS_ENABLED";
 
+        /// <summary>
+        /// Configuration key for a list of tags to be applied globally to spans.
+        /// </summary>
+        public const string GlobalTags = "DD_TRACE_GLOBAL_TAGS";
+
         /// <summary>
         /// Configuration key for enabling or disabling the automatic injection
         /// of correlation identifiers into the logging context.
diff --git a/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs b/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
index d545e076bc41..306b532f0a79 100644
--- a/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
@@ -1,3 +1,4 @@
+using System.Collections.Generic;
 using System.IO;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
@@ -97,5 +98,22 @@ public T GetValue<T>(string key)
                        ? default
                        : token.Value<T>();
         }
+
+        /// <summary>
+        /// Gets a Dictionary containing all of the configuration values where keys and values are strings.
+        /// </summary>
+        /// <returns>Dictionary of key value strings</returns>
+        public Dictionary<string, string> GetAllEntries()
+        {
+            var allEntries = new Dictionary<string, string>();
+            var enumerator = _configuration.GetEnumerator();
+
+            while (!enumerator.MoveNext())
+            {
+                allEntries.Add(enumerator.Current.Key, enumerator.Current.Value.ToString());
+            }
+
+            return allEntries;
+        }
     }
 }
diff --git a/src/Datadog.Trace/Configuration/TracerSettings.cs b/src/Datadog.Trace/Configuration/TracerSettings.cs
index 3d23593f9d76..c5e08c000193 100644
--- a/src/Datadog.Trace/Configuration/TracerSettings.cs
+++ b/src/Datadog.Trace/Configuration/TracerSettings.cs
@@ -76,6 +76,24 @@ public TracerSettings(IConfigurationSource source)
                                false;
 
             Integrations = new IntegrationSettingsCollection(source);
+
+            if (source == null)
+            {
+                GlobalTags = new Dictionary<string, string>();
+            }
+            else
+            {
+                var gTags = source.GetString(ConfigurationKeys.GlobalTags);
+                if (gTags != null)
+                {
+                    var gTagsConfig = new JsonConfigurationSource(gTags);
+                    GlobalTags = gTagsConfig.GetAllEntries();
+                }
+                else
+                {
+                    GlobalTags = new Dictionary<string, string>();
+                }
+            }
         }
 
         /// <summary>
@@ -141,6 +159,11 @@ public TracerSettings(IConfigurationSource source)
         /// </summary>
         public IntegrationSettingsCollection Integrations { get; }
 
+        /// <summary>
+        /// Gets or sets the global tags, which are applied to all <see cref="Span"/>s.
+        /// </summary>
+        public Dictionary<string, string> GlobalTags { get; set; }
+
         /// <summary>
         /// Create a <see cref="TracerSettings"/> populated from the default sources
         /// returned by <see cref="CreateDefaultConfigurationSource"/>.
diff --git a/src/Datadog.Trace/Datadog.Trace.csproj b/src/Datadog.Trace/Datadog.Trace.csproj
index 31bdec0add55..09ae389215da 100644
--- a/src/Datadog.Trace/Datadog.Trace.csproj
+++ b/src/Datadog.Trace/Datadog.Trace.csproj
@@ -6,6 +6,7 @@
     <Title>Datadog APM</Title>
     <Description>Manual instrumentation library for Datadog APM</Description>
     <Authors>lucas.pimentel.datadog;colinhigginsdatadog;zachmontoyadd</Authors>
+    <RunAnalyzersDuringBuild>true</RunAnalyzersDuringBuild>
   </PropertyGroup>
 
   <ItemGroup Condition=" '$(TargetFramework)' != 'netstandard2.0' ">
diff --git a/src/Datadog.Trace/Span.cs b/src/Datadog.Trace/Span.cs
index 2a8416379846..f667bb2b2501 100644
--- a/src/Datadog.Trace/Span.cs
+++ b/src/Datadog.Trace/Span.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Concurrent;
 using System.Globalization;
+using System.Linq;
 using System.Text;
 using Datadog.Trace.ExtensionMethods;
 using Datadog.Trace.Interfaces;
@@ -27,6 +28,15 @@ internal Span(SpanContext context, DateTimeOffset? start)
             ServiceName = context.ServiceName;
             StartTime = start ?? Context.TraceContext.UtcNow;
 
+            // Apply any global tags
+            if (Tracer.Instance.Settings.GlobalTags.Count > 0)
+                {
+                    foreach (var entry in Tracer.Instance.Settings.GlobalTags)
+                    {
+                        SetTag(entry.Key, entry.Value);
+                    }
+                }
+
             Log.Debug(
                 "Span started: [s_id: {0}, p_id: {1}, t_id: {2}]",
                 SpanId,
diff --git a/src/Datadog.Trace/Tracer.cs b/src/Datadog.Trace/Tracer.cs
index 073f01eafb3f..2f061cf647f0 100644
--- a/src/Datadog.Trace/Tracer.cs
+++ b/src/Datadog.Trace/Tracer.cs
@@ -221,6 +221,34 @@ public Span StartSpan(string operationName, ISpanContext parent = null, string s
             return span;
         }
 
+        /// <summary>
+        /// Adds the <paramref name="key"/>, <paramref name="value"/> pair as a global tag to be applied to all <see cref="Span"/>s.
+        /// </summary>
+        /// <param name="key">The global tag key</param>
+        /// <param name="value">The global tag value</param>
+        public void AddGlobalTag(string key, string value)
+        {
+            if (string.IsNullOrWhiteSpace(key))
+            {
+                Log.Warning("Cannot create a global tag with an empty key.");
+                return;
+            }
+
+            Tracer.Instance.Settings.GlobalTags.Add(key, value);
+        }
+
+        /// <summary>
+        /// Adds each <see cref="KeyValuePair{TKey, TValue}"/> in <paramref name="tags"/> as global tags.
+        /// </summary>
+        /// <param name="tags"><see cref="KeyValuePair{TKey, TValue}"/>s to be added as global tags.</param>
+        public void AddGlobalTags(IEnumerable<KeyValuePair<string, string>> tags)
+        {
+            foreach (var entry in tags)
+            {
+                Tracer.Instance.Settings.GlobalTags.Add(entry.Key, entry.Value);
+            }
+        }
+
         /// <summary>
         /// Writes the specified <see cref="Span"/> collection to the agent writer.
         /// </summary>
diff --git a/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs b/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
index 1fe2e0ee620e..b1280b8c5e7b 100644
--- a/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
+++ b/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
@@ -18,6 +18,7 @@ public static IEnumerable<object[]> GetDefaultTestData()
             yield return new object[] { CreateFunc(s => s.ServiceName), null };
             yield return new object[] { CreateFunc(s => s.DisabledIntegrationNames.Count), 0 };
             yield return new object[] { CreateFunc(s => s.LogsInjectionEnabled), false };
+            yield return new object[] { CreateFunc(s => s.GlobalTags.Count), 0 };
         }
 
         public static IEnumerable<object[]> GetTestData()
@@ -36,6 +37,8 @@ public static IEnumerable<object[]> GetTestData()
             yield return new object[] { ConfigurationKeys.ServiceName, "web-service", CreateFunc(s => s.ServiceName), "web-service" };
 
             yield return new object[] { ConfigurationKeys.DisabledIntegrations, "integration1;integration2", CreateFunc(s => s.DisabledIntegrationNames.Count), 2 };
+
+            yield return new object[] { ConfigurationKeys.GlobalTags, string.Empty, CreateFunc(s => s.GlobalTags.Count), 0 };
         }
 
         public static Func<TracerSettings, object> CreateFunc(Func<TracerSettings, object> settingGetter)
diff --git a/test/Datadog.Trace.Tests/Datadog.Trace.Tests.csproj b/test/Datadog.Trace.Tests/Datadog.Trace.Tests.csproj
index f8f2c539373a..a1d558c4f48b 100644
--- a/test/Datadog.Trace.Tests/Datadog.Trace.Tests.csproj
+++ b/test/Datadog.Trace.Tests/Datadog.Trace.Tests.csproj
@@ -1,5 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
+  <PropertyGroup>
+    <RunAnalyzersDuringBuild>true</RunAnalyzersDuringBuild>
+  </PropertyGroup>
+
   <ItemGroup>
     <PackageReference Include="log4net" Version="2.0.8" />
     <PackageReference Include="Newtonsoft.Json" Version="12.0.1" />
diff --git a/test/Datadog.Trace.Tests/TracerTests.cs b/test/Datadog.Trace.Tests/TracerTests.cs
index 96ee8d5d2faa..ee79bc97a92c 100644
--- a/test/Datadog.Trace.Tests/TracerTests.cs
+++ b/test/Datadog.Trace.Tests/TracerTests.cs
@@ -337,5 +337,18 @@ public void SetServiceName(string envServiceName, string tracerServiceName, stri
             // reset the environment variable to its original values (if any) when done
             Environment.SetEnvironmentVariable(name, originalEnv);
         }
+
+        [Theory]
+        [InlineData(null, null)]
+        [InlineData(null, "")]
+        [InlineData("", null)]
+        [InlineData("", "avalue")]
+        public void AddGlobalTag(string key, string value)
+        {
+            _tracer.AddGlobalTag(key, value);
+
+            Assert.Single(_tracer.Settings.GlobalTags);
+            Assert.Equal(value, _tracer.Settings.GlobalTags[key]);
+        }
     }
 }

From 6eadd942f177f8a125ada4bbd13c70e04a58ed52 Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Mon, 21 Oct 2019 10:39:15 -0700
Subject: [PATCH 02/13] AddGlobalTag and AddGlobalTags API and unit tests

---
 .../Configuration/JsonConfigurationSource.cs  | 17 -----
 .../Configuration/TracerSettings.cs           |  4 +-
 src/Datadog.Trace/Tracer.cs                   |  5 +-
 test/Datadog.Trace.Tests/TracerTests.cs       | 65 +++++++++++++++++--
 4 files changed, 63 insertions(+), 28 deletions(-)

diff --git a/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs b/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
index 306b532f0a79..e729bc7812ff 100644
--- a/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
@@ -98,22 +98,5 @@ public T GetValue<T>(string key)
                        ? default
                        : token.Value<T>();
         }
-
-        /// <summary>
-        /// Gets a Dictionary containing all of the configuration values where keys and values are strings.
-        /// </summary>
-        /// <returns>Dictionary of key value strings</returns>
-        public Dictionary<string, string> GetAllEntries()
-        {
-            var allEntries = new Dictionary<string, string>();
-            var enumerator = _configuration.GetEnumerator();
-
-            while (!enumerator.MoveNext())
-            {
-                allEntries.Add(enumerator.Current.Key, enumerator.Current.Value.ToString());
-            }
-
-            return allEntries;
-        }
     }
 }
diff --git a/src/Datadog.Trace/Configuration/TracerSettings.cs b/src/Datadog.Trace/Configuration/TracerSettings.cs
index c5e08c000193..9f62cdf8c2d3 100644
--- a/src/Datadog.Trace/Configuration/TracerSettings.cs
+++ b/src/Datadog.Trace/Configuration/TracerSettings.cs
@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using Newtonsoft.Json;
 
 namespace Datadog.Trace.Configuration
 {
@@ -86,8 +87,7 @@ public TracerSettings(IConfigurationSource source)
                 var gTags = source.GetString(ConfigurationKeys.GlobalTags);
                 if (gTags != null)
                 {
-                    var gTagsConfig = new JsonConfigurationSource(gTags);
-                    GlobalTags = gTagsConfig.GetAllEntries();
+                    GlobalTags = JsonConvert.DeserializeObject<Dictionary<string, string>>(gTags);
                 }
                 else
                 {
diff --git a/src/Datadog.Trace/Tracer.cs b/src/Datadog.Trace/Tracer.cs
index 2f061cf647f0..c7c607a6c30b 100644
--- a/src/Datadog.Trace/Tracer.cs
+++ b/src/Datadog.Trace/Tracer.cs
@@ -224,6 +224,7 @@ public Span StartSpan(string operationName, ISpanContext parent = null, string s
         /// <summary>
         /// Adds the <paramref name="key"/>, <paramref name="value"/> pair as a global tag to be applied to all <see cref="Span"/>s.
         /// </summary>
+        /// <remarks><paramref name="key"/> is whitespace-trimmed before being added.</remarks>
         /// <param name="key">The global tag key</param>
         /// <param name="value">The global tag value</param>
         public void AddGlobalTag(string key, string value)
@@ -234,7 +235,7 @@ public void AddGlobalTag(string key, string value)
                 return;
             }
 
-            Tracer.Instance.Settings.GlobalTags.Add(key, value);
+            Settings.GlobalTags[key.Trim()] = value;
         }
 
         /// <summary>
@@ -245,7 +246,7 @@ public void AddGlobalTags(IEnumerable<KeyValuePair<string, string>> tags)
         {
             foreach (var entry in tags)
             {
-                Tracer.Instance.Settings.GlobalTags.Add(entry.Key, entry.Value);
+                AddGlobalTag(entry.Key, entry.Value);
             }
         }
 
diff --git a/test/Datadog.Trace.Tests/TracerTests.cs b/test/Datadog.Trace.Tests/TracerTests.cs
index ee79bc97a92c..b117cf0336c2 100644
--- a/test/Datadog.Trace.Tests/TracerTests.cs
+++ b/test/Datadog.Trace.Tests/TracerTests.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using Datadog.Trace.Agent;
@@ -339,16 +340,66 @@ public void SetServiceName(string envServiceName, string tracerServiceName, stri
         }
 
         [Theory]
-        [InlineData(null, null)]
-        [InlineData(null, "")]
-        [InlineData("", null)]
-        [InlineData("", "avalue")]
-        public void AddGlobalTag(string key, string value)
+        [InlineData(null, null, 0)]
+        [InlineData(null, "", 0)]
+        [InlineData("", null, 0)]
+        [InlineData("", "avalue", 0)]
+        [InlineData(" ", "123", 0)]
+        [InlineData("key1", "value1", 1)]
+        [InlineData("key1", null, 1)]
+        [InlineData("key1", "", 1)]
+        public void AddGlobalTag(string key, string value, int expectedCount)
         {
             _tracer.AddGlobalTag(key, value);
 
-            Assert.Single(_tracer.Settings.GlobalTags);
-            Assert.Equal(value, _tracer.Settings.GlobalTags[key]);
+            Assert.Equal(expectedCount, _tracer.Settings.GlobalTags.Count);
+        }
+
+        [Fact]
+        public void AddGlobalTag_OverwriteExpected()
+        {
+            string key = "k1";
+            string firstvalue = "v1";
+            string lastValue = "asdf";
+
+            _tracer.AddGlobalTag(key, firstvalue);
+            _tracer.AddGlobalTag(key, lastValue);
+
+            Assert.True(_tracer.Settings.GlobalTags.Count == 1);
+            Assert.True(_tracer.Settings.GlobalTags[key] == lastValue);
+        }
+
+        [Fact]
+        public void AddGlobalTags_AllValid()
+        {
+            var tags = new Dictionary<string, string>()
+            {
+                { "k1", "v1" },
+                { "k2", string.Empty },
+                { "k3", null }
+            };
+
+            _tracer.AddGlobalTags(tags);
+
+            Assert.Equal(tags.Count, _tracer.Settings.GlobalTags.Count);
+        }
+
+        [Fact]
+        public void AddGlobalTags_IncludesTwoInValidKeys()
+        {
+            var tags = new Dictionary<string, string>()
+            {
+                { "k1", "v1" },
+                { "k2", string.Empty },
+                { "k3", null },
+                { string.Empty, "yo" },
+                { "abc", "def" },
+                { "    ", "xyz" }
+            };
+
+            _tracer.AddGlobalTags(tags);
+
+            Assert.Equal(tags.Count - 2, _tracer.Settings.GlobalTags.Count);
         }
     }
 }

From 74841fd1b8da0ddb93e4703bbfe359038930809c Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Mon, 21 Oct 2019 12:14:08 -0700
Subject: [PATCH 03/13] ConfigurationSource tests passing; Tests validating
 spans are tagged

---
 src/Datadog.Trace/IDatadogTracer.cs           |  3 ++
 src/Datadog.Trace/Span.cs                     | 10 ----
 src/Datadog.Trace/Tracer.cs                   |  9 ++++
 .../Configuration/ConfigurationSourceTests.cs |  2 +-
 test/Datadog.Trace.Tests/TracerTests.cs       | 51 +++++++++++++++++++
 5 files changed, 64 insertions(+), 11 deletions(-)

diff --git a/src/Datadog.Trace/IDatadogTracer.cs b/src/Datadog.Trace/IDatadogTracer.cs
index 28ea43cd6112..227842e9fb21 100644
--- a/src/Datadog.Trace/IDatadogTracer.cs
+++ b/src/Datadog.Trace/IDatadogTracer.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using Datadog.Trace.Configuration;
 using Datadog.Trace.Sampling;
 
 namespace Datadog.Trace
@@ -14,6 +15,8 @@ internal interface IDatadogTracer
 
         ISampler Sampler { get; }
 
+        TracerSettings Settings { get; }
+
         Span StartSpan(string operationName, ISpanContext parent, string serviceName, DateTimeOffset? startTime, bool ignoreActiveScope);
 
         void Write(List<Span> span);
diff --git a/src/Datadog.Trace/Span.cs b/src/Datadog.Trace/Span.cs
index f667bb2b2501..2a8416379846 100644
--- a/src/Datadog.Trace/Span.cs
+++ b/src/Datadog.Trace/Span.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Concurrent;
 using System.Globalization;
-using System.Linq;
 using System.Text;
 using Datadog.Trace.ExtensionMethods;
 using Datadog.Trace.Interfaces;
@@ -28,15 +27,6 @@ internal Span(SpanContext context, DateTimeOffset? start)
             ServiceName = context.ServiceName;
             StartTime = start ?? Context.TraceContext.UtcNow;
 
-            // Apply any global tags
-            if (Tracer.Instance.Settings.GlobalTags.Count > 0)
-                {
-                    foreach (var entry in Tracer.Instance.Settings.GlobalTags)
-                    {
-                        SetTag(entry.Key, entry.Value);
-                    }
-                }
-
             Log.Debug(
                 "Span started: [s_id: {0}, p_id: {1}, t_id: {2}]",
                 SpanId,
diff --git a/src/Datadog.Trace/Tracer.cs b/src/Datadog.Trace/Tracer.cs
index c7c607a6c30b..c76fda6ca227 100644
--- a/src/Datadog.Trace/Tracer.cs
+++ b/src/Datadog.Trace/Tracer.cs
@@ -217,6 +217,15 @@ public Span StartSpan(string operationName, ISpanContext parent = null, string s
                 span.SetTag(Tags.Env, env);
             }
 
+            // Apply any global tags
+            if (((TraceContext)traceContext).Tracer.Settings.GlobalTags.Count > 0)
+            {
+                foreach (var entry in ((TraceContext)traceContext).Tracer.Settings.GlobalTags)
+                {
+                    span.SetTag(entry.Key, entry.Value);
+                }
+            }
+
             traceContext.AddSpan(span);
             return span;
         }
diff --git a/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs b/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
index b1280b8c5e7b..71cbc134eee9 100644
--- a/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
+++ b/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
@@ -38,7 +38,7 @@ public static IEnumerable<object[]> GetTestData()
 
             yield return new object[] { ConfigurationKeys.DisabledIntegrations, "integration1;integration2", CreateFunc(s => s.DisabledIntegrationNames.Count), 2 };
 
-            yield return new object[] { ConfigurationKeys.GlobalTags, string.Empty, CreateFunc(s => s.GlobalTags.Count), 0 };
+            yield return new object[] { ConfigurationKeys.GlobalTags, "{ 'k1':'v1', 'k2':'v2' }", CreateFunc(s => s.GlobalTags.Count), 2 };
         }
 
         public static Func<TracerSettings, object> CreateFunc(Func<TracerSettings, object> settingGetter)
diff --git a/test/Datadog.Trace.Tests/TracerTests.cs b/test/Datadog.Trace.Tests/TracerTests.cs
index b117cf0336c2..7768affa28bf 100644
--- a/test/Datadog.Trace.Tests/TracerTests.cs
+++ b/test/Datadog.Trace.Tests/TracerTests.cs
@@ -167,6 +167,32 @@ public void StartActive_SetStartTime_StartTimeIsProperlySet()
             Assert.Equal(startTime, scope.Span.StartTime);
         }
 
+        [Fact]
+        public void StartActive_GlobalTag_IsSet()
+        {
+            var key = "myTag";
+            var value = "myValue";
+
+            _tracer.AddGlobalTag(key, value);
+
+            var scope = _tracer.StartActive("Operation");
+
+            Assert.Equal(value, scope.Span.GetTag(key));
+        }
+
+        [Fact]
+        public void StartManual_GlobalTag_IsSet()
+        {
+            var key = "myTag";
+            var value = "myValue";
+
+            _tracer.AddGlobalTag(key, value);
+
+            var span = _tracer.StartSpan("Operation", null);
+
+            Assert.Equal(value, span.GetTag(key));
+        }
+
         [Fact]
         public void StartManual_SetOperationName_OperationNameIsSet()
         {
@@ -238,6 +264,31 @@ public void StartActive_2LevelChildren_ChildrenParentProperlySet()
             Assert.Equal(child1.Span.Context.SpanId, child2.Span.Context.ParentId);
         }
 
+        [Fact]
+        public void StartActive_2ChildrenOfRoot_GlobalTagsProperlySet()
+        {
+            var key1 = "t1";
+            var value1 = "terminator";
+            var key2 = "t2";
+            var value2 = "terminatrix";
+
+            _tracer.AddGlobalTag(key1, value1);
+            _tracer.AddGlobalTag(key2, value2);
+
+            var root = _tracer.StartActive("Root");
+            var child1 = _tracer.StartActive("Child1");
+            child1.Dispose();
+            var child2 = _tracer.StartActive("Child2");
+
+            Assert.Equal(value1, root.Span.GetTag(key1));
+            Assert.Equal(value1, child1.Span.GetTag(key1));
+            Assert.Equal(value1, child2.Span.GetTag(key1));
+
+            Assert.Equal(value2, root.Span.GetTag(key2));
+            Assert.Equal(value2, child1.Span.GetTag(key2));
+            Assert.Equal(value2, child2.Span.GetTag(key2));
+        }
+
         [Fact]
         public async Task StartActive_AsyncChildrenCreation_ChildrenParentProperlySet()
         {

From e28ad1bd87d35d9167c4c01fbbdfdf6e7e93464e Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Mon, 21 Oct 2019 15:40:04 -0700
Subject: [PATCH 04/13] Remove GlobalTag API methods and tests per decision to
 have just config settings

---
 .../Configuration/TracerSettings.cs           |  14 +--
 src/Datadog.Trace/Datadog.Trace.csproj        |   1 -
 src/Datadog.Trace/Tracer.cs                   |  33 +----
 test/Datadog.Trace.Tests/TracerTests.cs       | 114 ------------------
 4 files changed, 6 insertions(+), 156 deletions(-)

diff --git a/src/Datadog.Trace/Configuration/TracerSettings.cs b/src/Datadog.Trace/Configuration/TracerSettings.cs
index 9f62cdf8c2d3..9c767da6848f 100644
--- a/src/Datadog.Trace/Configuration/TracerSettings.cs
+++ b/src/Datadog.Trace/Configuration/TracerSettings.cs
@@ -78,21 +78,15 @@ public TracerSettings(IConfigurationSource source)
 
             Integrations = new IntegrationSettingsCollection(source);
 
-            if (source == null)
+            var gTags = source?.GetString(ConfigurationKeys.GlobalTags);
+
+            if (gTags == null)
             {
                 GlobalTags = new Dictionary<string, string>();
             }
             else
             {
-                var gTags = source.GetString(ConfigurationKeys.GlobalTags);
-                if (gTags != null)
-                {
-                    GlobalTags = JsonConvert.DeserializeObject<Dictionary<string, string>>(gTags);
-                }
-                else
-                {
-                    GlobalTags = new Dictionary<string, string>();
-                }
+                GlobalTags = JsonConvert.DeserializeObject<Dictionary<string, string>>(gTags);
             }
         }
 
diff --git a/src/Datadog.Trace/Datadog.Trace.csproj b/src/Datadog.Trace/Datadog.Trace.csproj
index 09ae389215da..31bdec0add55 100644
--- a/src/Datadog.Trace/Datadog.Trace.csproj
+++ b/src/Datadog.Trace/Datadog.Trace.csproj
@@ -6,7 +6,6 @@
     <Title>Datadog APM</Title>
     <Description>Manual instrumentation library for Datadog APM</Description>
     <Authors>lucas.pimentel.datadog;colinhigginsdatadog;zachmontoyadd</Authors>
-    <RunAnalyzersDuringBuild>true</RunAnalyzersDuringBuild>
   </PropertyGroup>
 
   <ItemGroup Condition=" '$(TargetFramework)' != 'netstandard2.0' ">
diff --git a/src/Datadog.Trace/Tracer.cs b/src/Datadog.Trace/Tracer.cs
index c76fda6ca227..609716248dd1 100644
--- a/src/Datadog.Trace/Tracer.cs
+++ b/src/Datadog.Trace/Tracer.cs
@@ -218,9 +218,9 @@ public Span StartSpan(string operationName, ISpanContext parent = null, string s
             }
 
             // Apply any global tags
-            if (((TraceContext)traceContext).Tracer.Settings.GlobalTags.Count > 0)
+            if (Settings.GlobalTags.Count > 0)
             {
-                foreach (var entry in ((TraceContext)traceContext).Tracer.Settings.GlobalTags)
+                foreach (var entry in Settings.GlobalTags)
                 {
                     span.SetTag(entry.Key, entry.Value);
                 }
@@ -230,35 +230,6 @@ public Span StartSpan(string operationName, ISpanContext parent = null, string s
             return span;
         }
 
-        /// <summary>
-        /// Adds the <paramref name="key"/>, <paramref name="value"/> pair as a global tag to be applied to all <see cref="Span"/>s.
-        /// </summary>
-        /// <remarks><paramref name="key"/> is whitespace-trimmed before being added.</remarks>
-        /// <param name="key">The global tag key</param>
-        /// <param name="value">The global tag value</param>
-        public void AddGlobalTag(string key, string value)
-        {
-            if (string.IsNullOrWhiteSpace(key))
-            {
-                Log.Warning("Cannot create a global tag with an empty key.");
-                return;
-            }
-
-            Settings.GlobalTags[key.Trim()] = value;
-        }
-
-        /// <summary>
-        /// Adds each <see cref="KeyValuePair{TKey, TValue}"/> in <paramref name="tags"/> as global tags.
-        /// </summary>
-        /// <param name="tags"><see cref="KeyValuePair{TKey, TValue}"/>s to be added as global tags.</param>
-        public void AddGlobalTags(IEnumerable<KeyValuePair<string, string>> tags)
-        {
-            foreach (var entry in tags)
-            {
-                AddGlobalTag(entry.Key, entry.Value);
-            }
-        }
-
         /// <summary>
         /// Writes the specified <see cref="Span"/> collection to the agent writer.
         /// </summary>
diff --git a/test/Datadog.Trace.Tests/TracerTests.cs b/test/Datadog.Trace.Tests/TracerTests.cs
index 7768affa28bf..0b70014d973d 100644
--- a/test/Datadog.Trace.Tests/TracerTests.cs
+++ b/test/Datadog.Trace.Tests/TracerTests.cs
@@ -167,32 +167,6 @@ public void StartActive_SetStartTime_StartTimeIsProperlySet()
             Assert.Equal(startTime, scope.Span.StartTime);
         }
 
-        [Fact]
-        public void StartActive_GlobalTag_IsSet()
-        {
-            var key = "myTag";
-            var value = "myValue";
-
-            _tracer.AddGlobalTag(key, value);
-
-            var scope = _tracer.StartActive("Operation");
-
-            Assert.Equal(value, scope.Span.GetTag(key));
-        }
-
-        [Fact]
-        public void StartManual_GlobalTag_IsSet()
-        {
-            var key = "myTag";
-            var value = "myValue";
-
-            _tracer.AddGlobalTag(key, value);
-
-            var span = _tracer.StartSpan("Operation", null);
-
-            Assert.Equal(value, span.GetTag(key));
-        }
-
         [Fact]
         public void StartManual_SetOperationName_OperationNameIsSet()
         {
@@ -264,31 +238,6 @@ public void StartActive_2LevelChildren_ChildrenParentProperlySet()
             Assert.Equal(child1.Span.Context.SpanId, child2.Span.Context.ParentId);
         }
 
-        [Fact]
-        public void StartActive_2ChildrenOfRoot_GlobalTagsProperlySet()
-        {
-            var key1 = "t1";
-            var value1 = "terminator";
-            var key2 = "t2";
-            var value2 = "terminatrix";
-
-            _tracer.AddGlobalTag(key1, value1);
-            _tracer.AddGlobalTag(key2, value2);
-
-            var root = _tracer.StartActive("Root");
-            var child1 = _tracer.StartActive("Child1");
-            child1.Dispose();
-            var child2 = _tracer.StartActive("Child2");
-
-            Assert.Equal(value1, root.Span.GetTag(key1));
-            Assert.Equal(value1, child1.Span.GetTag(key1));
-            Assert.Equal(value1, child2.Span.GetTag(key1));
-
-            Assert.Equal(value2, root.Span.GetTag(key2));
-            Assert.Equal(value2, child1.Span.GetTag(key2));
-            Assert.Equal(value2, child2.Span.GetTag(key2));
-        }
-
         [Fact]
         public async Task StartActive_AsyncChildrenCreation_ChildrenParentProperlySet()
         {
@@ -389,68 +338,5 @@ public void SetServiceName(string envServiceName, string tracerServiceName, stri
             // reset the environment variable to its original values (if any) when done
             Environment.SetEnvironmentVariable(name, originalEnv);
         }
-
-        [Theory]
-        [InlineData(null, null, 0)]
-        [InlineData(null, "", 0)]
-        [InlineData("", null, 0)]
-        [InlineData("", "avalue", 0)]
-        [InlineData(" ", "123", 0)]
-        [InlineData("key1", "value1", 1)]
-        [InlineData("key1", null, 1)]
-        [InlineData("key1", "", 1)]
-        public void AddGlobalTag(string key, string value, int expectedCount)
-        {
-            _tracer.AddGlobalTag(key, value);
-
-            Assert.Equal(expectedCount, _tracer.Settings.GlobalTags.Count);
-        }
-
-        [Fact]
-        public void AddGlobalTag_OverwriteExpected()
-        {
-            string key = "k1";
-            string firstvalue = "v1";
-            string lastValue = "asdf";
-
-            _tracer.AddGlobalTag(key, firstvalue);
-            _tracer.AddGlobalTag(key, lastValue);
-
-            Assert.True(_tracer.Settings.GlobalTags.Count == 1);
-            Assert.True(_tracer.Settings.GlobalTags[key] == lastValue);
-        }
-
-        [Fact]
-        public void AddGlobalTags_AllValid()
-        {
-            var tags = new Dictionary<string, string>()
-            {
-                { "k1", "v1" },
-                { "k2", string.Empty },
-                { "k3", null }
-            };
-
-            _tracer.AddGlobalTags(tags);
-
-            Assert.Equal(tags.Count, _tracer.Settings.GlobalTags.Count);
-        }
-
-        [Fact]
-        public void AddGlobalTags_IncludesTwoInValidKeys()
-        {
-            var tags = new Dictionary<string, string>()
-            {
-                { "k1", "v1" },
-                { "k2", string.Empty },
-                { "k3", null },
-                { string.Empty, "yo" },
-                { "abc", "def" },
-                { "    ", "xyz" }
-            };
-
-            _tracer.AddGlobalTags(tags);
-
-            Assert.Equal(tags.Count - 2, _tracer.Settings.GlobalTags.Count);
-        }
     }
 }

From 0cf842865c7d0dbb0630a116df941596522406d5 Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Mon, 21 Oct 2019 18:57:31 -0700
Subject: [PATCH 05/13] Change global tag configuration data format to csv of
 key-value pairs

---
 .../CsvMapConfigurationSource.cs              | 60 +++++++++++++++++++
 .../Configuration/TracerSettings.cs           |  8 ++-
 .../Configuration/ConfigurationSourceTests.cs |  2 +-
 3 files changed, 66 insertions(+), 4 deletions(-)
 create mode 100644 src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs

diff --git a/src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs b/src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs
new file mode 100644
index 000000000000..faa6df838005
--- /dev/null
+++ b/src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs
@@ -0,0 +1,60 @@
+using System;
+using System.Collections.Concurrent;
+
+namespace Datadog.Trace.Configuration
+{
+    /// <summary>
+    /// Represents a configuration source that retrieves values from
+    /// a comma-separate list of key-value pairs.
+    /// </summary>
+    public class CsvMapConfigurationSource : StringConfigurationSource
+    {
+        private ConcurrentDictionary<string, string> _data;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CsvMapConfigurationSource"/> class
+        /// using a custom configuration string format.
+        /// </summary>
+        /// <param name="config">Configuration string that is a comma-separated list of key, value pairs where key and value are colon-separated.</param>
+        /// <example>An example configuration string would be "'globalTag1':'someValue','globalTag2':'anotherValue'"</example>
+        public CsvMapConfigurationSource(string config)
+        {
+            _data = ParseConfig(config);
+        }
+
+        /// <summary>
+        /// Gets the configuration data as a <see cref="ConcurrentDictionary{TKey, TValue}"/>
+        /// </summary>
+        public ConcurrentDictionary<string, string> Data
+        {
+            get { return _data; }
+        }
+
+        /// <inheritdoc />
+        public override string GetString(string key)
+        {
+            throw new NotImplementedException();
+        }
+
+        private ConcurrentDictionary<string, string> ParseConfig(string config)
+        {
+            ConcurrentDictionary<string, string> data = new ConcurrentDictionary<string, string>();
+
+            var entries = config.Split(',');
+            foreach (var e in entries)
+            {
+                var kv = e.Split(':');
+                if (kv.Length != 2)
+                {
+                    continue;
+                }
+
+                var key = kv[0];
+                var value = kv[1];
+                data[key] = value;
+            }
+
+            return data;
+        }
+    }
+}
diff --git a/src/Datadog.Trace/Configuration/TracerSettings.cs b/src/Datadog.Trace/Configuration/TracerSettings.cs
index 9c767da6848f..28b857aaee72 100644
--- a/src/Datadog.Trace/Configuration/TracerSettings.cs
+++ b/src/Datadog.Trace/Configuration/TracerSettings.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -82,11 +83,12 @@ public TracerSettings(IConfigurationSource source)
 
             if (gTags == null)
             {
-                GlobalTags = new Dictionary<string, string>();
+                GlobalTags = new ConcurrentDictionary<string, string>();
             }
             else
             {
-                GlobalTags = JsonConvert.DeserializeObject<Dictionary<string, string>>(gTags);
+                var csvMapConfig = new CsvMapConfigurationSource(gTags);
+                GlobalTags = csvMapConfig.Data;
             }
         }
 
@@ -156,7 +158,7 @@ public TracerSettings(IConfigurationSource source)
         /// <summary>
         /// Gets or sets the global tags, which are applied to all <see cref="Span"/>s.
         /// </summary>
-        public Dictionary<string, string> GlobalTags { get; set; }
+        public ConcurrentDictionary<string, string> GlobalTags { get; set; }
 
         /// <summary>
         /// Create a <see cref="TracerSettings"/> populated from the default sources
diff --git a/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs b/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
index 71cbc134eee9..97771196e6f0 100644
--- a/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
+++ b/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
@@ -38,7 +38,7 @@ public static IEnumerable<object[]> GetTestData()
 
             yield return new object[] { ConfigurationKeys.DisabledIntegrations, "integration1;integration2", CreateFunc(s => s.DisabledIntegrationNames.Count), 2 };
 
-            yield return new object[] { ConfigurationKeys.GlobalTags, "{ 'k1':'v1', 'k2':'v2' }", CreateFunc(s => s.GlobalTags.Count), 2 };
+            yield return new object[] { ConfigurationKeys.GlobalTags, "'k1':'v1', 'k2':'v2'", CreateFunc(s => s.GlobalTags.Count), 2 };
         }
 
         public static Func<TracerSettings, object> CreateFunc(Func<TracerSettings, object> settingGetter)

From cdeecff14077e68d19539f148c48a20718c5b496 Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Wed, 23 Oct 2019 10:31:50 -0700
Subject: [PATCH 06/13] var instead of actual type

---
 src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs b/src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs
index faa6df838005..d2b548b8ecdc 100644
--- a/src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs
@@ -38,7 +38,7 @@ public override string GetString(string key)
 
         private ConcurrentDictionary<string, string> ParseConfig(string config)
         {
-            ConcurrentDictionary<string, string> data = new ConcurrentDictionary<string, string>();
+            var data = new ConcurrentDictionary<string, string>();
 
             var entries = config.Split(',');
             foreach (var e in entries)

From 92d20a17074d1c2b32c8b88237686a0086843b4e Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Thu, 24 Oct 2019 17:22:07 -0700
Subject: [PATCH 07/13] Support Dictionary as a configuration value, initially
 just used for Global Tags

---
 .../CompositeConfigurationSource.cs           |  8 ++++
 .../EnvironmentConfigurationSource.cs         |  2 +-
 .../Configuration/IConfigurationSource.cs     | 12 ++++-
 .../Configuration/JsonConfigurationSource.cs  | 36 +++++++++++++++
 .../StringConfigurationSource.cs              | 46 +++++++++++++++++++
 .../Configuration/TracerSettings.cs           | 13 +-----
 ....Trace.ClrProfiler.IntegrationTests.csproj | 12 ++---
 .../Configuration/ConfigurationSourceTests.cs | 30 +++++++++++-
 8 files changed, 136 insertions(+), 23 deletions(-)

diff --git a/src/Datadog.Trace/Configuration/CompositeConfigurationSource.cs b/src/Datadog.Trace/Configuration/CompositeConfigurationSource.cs
index 6e5037b91434..9baf8be4df69 100644
--- a/src/Datadog.Trace/Configuration/CompositeConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/CompositeConfigurationSource.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -98,5 +99,12 @@ IEnumerator IEnumerable.GetEnumerator()
         {
             return _sources.GetEnumerator();
         }
+
+        /// <inheritdoc />
+        public IDictionary<string, string> GetDictionary(string key)
+        {
+            return _sources.Select(source => source.GetDictionary(key))
+                        .FirstOrDefault(value => value != null);
+        }
     }
 }
diff --git a/src/Datadog.Trace/Configuration/EnvironmentConfigurationSource.cs b/src/Datadog.Trace/Configuration/EnvironmentConfigurationSource.cs
index 016bc22af7a7..21e5d193c807 100644
--- a/src/Datadog.Trace/Configuration/EnvironmentConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/EnvironmentConfigurationSource.cs
@@ -13,5 +13,5 @@ public override string GetString(string key)
         {
             return Environment.GetEnvironmentVariable(key);
         }
-    }
+   }
 }
diff --git a/src/Datadog.Trace/Configuration/IConfigurationSource.cs b/src/Datadog.Trace/Configuration/IConfigurationSource.cs
index 1a62c505b770..d3e46e871289 100644
--- a/src/Datadog.Trace/Configuration/IConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/IConfigurationSource.cs
@@ -1,3 +1,5 @@
+using System.Collections.Generic;
+
 namespace Datadog.Trace.Configuration
 {
     /// <summary>
@@ -36,5 +38,13 @@ public interface IConfigurationSource
         /// <param name="key">The key that identifies the setting.</param>
         /// <returns>The value of the setting, or <c>null</c> if not found.</returns>
         bool? GetBool(string key);
-    }
+
+        /// <summary>
+        /// Gets the <see cref="IDictionary{TKey, TValue}"/> value of
+        /// the setting with the specified key.
+        /// </summary>
+        /// <param name="key">The key that identifies the setting.</param>
+        /// <returns>The value of the setting, or <c>null</c> if not found.</returns>
+        IDictionary<string, string> GetDictionary(string key);
+   }
 }
diff --git a/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs b/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
index e729bc7812ff..5ec3e79f0401 100644
--- a/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
@@ -1,3 +1,4 @@
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.IO;
 using Newtonsoft.Json;
@@ -98,5 +99,40 @@ public T GetValue<T>(string key)
                        ? default
                        : token.Value<T>();
         }
+
+        /// <summary>
+        /// Gets a <see cref="ConcurrentDictionary{TKey, TValue}"/> containing all of the values.
+        /// </summary>
+        /// <remarks>
+        /// Example JSON where `globalTags` is the configuration key.
+        /// {
+        ///  "globalTags": {
+        ///     "name1": "value1",
+        ///     "name2": "value2"
+        ///     }
+        /// }
+        /// </remarks>
+        /// <param name="key">The key that identifies the setting.</param>
+        /// <returns><see cref="IDictionary{TKey, TValue}"/> containing all of the key-value pairs.</returns>
+        /// <exception cref="JsonReaderException">Thrown if the configuration value is not a valid JSON string.</exception>"
+        public IDictionary<string, string> GetDictionary(string key)
+        {
+            var token = _configuration.SelectToken(key, errorWhenNoMatch: false);
+            if (token == null)
+            {
+                return null;
+            }
+
+            // Presence of a curly brace indicates that this is likely a JSON string. An exception will be thrown
+            // if it fails to parse or convert to a dictionary.
+            if (token.ToString().Contains("{"))
+            {
+                var dictionary = JToken.Parse(token.ToString())
+                    ?.ToObject(typeof(ConcurrentDictionary<string, string>)) as ConcurrentDictionary<string, string>;
+                return dictionary;
+            }
+
+            return StringConfigurationSource.ParseCustomKeyValues(token.ToString());
+        }
     }
 }
diff --git a/src/Datadog.Trace/Configuration/StringConfigurationSource.cs b/src/Datadog.Trace/Configuration/StringConfigurationSource.cs
index 4b0aa3748dd4..e4d3075d9e19 100644
--- a/src/Datadog.Trace/Configuration/StringConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/StringConfigurationSource.cs
@@ -1,3 +1,6 @@
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+
 namespace Datadog.Trace.Configuration
 {
     /// <summary>
@@ -6,6 +9,39 @@ namespace Datadog.Trace.Configuration
     /// </summary>
     public abstract class StringConfigurationSource : IConfigurationSource
     {
+        /// <summary>
+        /// Returns a <see cref="IDictionary{TKey, TValue}"/> from parsing
+        /// <paramref name="data"/>.
+        /// </summary>
+        /// <param name="data">A string containing key-value pairs which are comma-separated, and for which the key and value are colon-separated.</param>
+        /// <returns><see cref="IDictionary{TKey, TValue}"/> of key value pairs.</returns>
+        public static IDictionary<string, string> ParseCustomKeyValues(string data)
+        {
+            var dictionary = new ConcurrentDictionary<string, string>();
+
+            if (data == null)
+            {
+                return dictionary;
+            }
+
+            var entries = data.Split(',');
+
+            foreach (var e in entries)
+            {
+                var kv = e.Split(':');
+                if (kv.Length != 2)
+                {
+                    continue;
+                }
+
+                var key = kv[0];
+                var value = kv[1];
+                dictionary[key] = value;
+            }
+
+            return dictionary;
+        }
+
         /// <inheritdoc />
         public abstract string GetString(string key);
 
@@ -38,5 +74,15 @@ public abstract class StringConfigurationSource : IConfigurationSource
                        ? result
                        : (bool?)null;
         }
+
+        /// <summary>
+        /// Gets a <see cref="ConcurrentDictionary{TKey, TValue}"/> from parsing
+        /// </summary>
+        /// <param name="key">The key</param>
+        /// <returns><see cref="ConcurrentDictionary{TKey, TValue}"/> containing all of the key-value pairs.</returns>
+        public IDictionary<string, string> GetDictionary(string key)
+        {
+            return ParseCustomKeyValues(GetString(key));
+        }
     }
 }
diff --git a/src/Datadog.Trace/Configuration/TracerSettings.cs b/src/Datadog.Trace/Configuration/TracerSettings.cs
index 28b857aaee72..04c749c0352b 100644
--- a/src/Datadog.Trace/Configuration/TracerSettings.cs
+++ b/src/Datadog.Trace/Configuration/TracerSettings.cs
@@ -79,17 +79,8 @@ public TracerSettings(IConfigurationSource source)
 
             Integrations = new IntegrationSettingsCollection(source);
 
-            var gTags = source?.GetString(ConfigurationKeys.GlobalTags);
-
-            if (gTags == null)
-            {
-                GlobalTags = new ConcurrentDictionary<string, string>();
-            }
-            else
-            {
-                var csvMapConfig = new CsvMapConfigurationSource(gTags);
-                GlobalTags = csvMapConfig.Data;
-            }
+            GlobalTags = source?.GetDictionary(ConfigurationKeys.GlobalTags) as ConcurrentDictionary<string, string> ??
+                new ConcurrentDictionary<string, string>();
         }
 
         /// <summary>
diff --git a/test/Datadog.Trace.ClrProfiler.IntegrationTests/Datadog.Trace.ClrProfiler.IntegrationTests.csproj b/test/Datadog.Trace.ClrProfiler.IntegrationTests/Datadog.Trace.ClrProfiler.IntegrationTests.csproj
index 27fbd33f27c6..a30c20310a1b 100644
--- a/test/Datadog.Trace.ClrProfiler.IntegrationTests/Datadog.Trace.ClrProfiler.IntegrationTests.csproj
+++ b/test/Datadog.Trace.ClrProfiler.IntegrationTests/Datadog.Trace.ClrProfiler.IntegrationTests.csproj
@@ -6,14 +6,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <None Include="..\..\src\Datadog.Trace.ClrProfiler.Native\bin\$(Configuration)\$(Platform)\**"
-             CopyToOutputDirectory="Always"
-             CopyToPublishDirectory="Always"
-             Link="profiler-lib\%(RecursiveDir)\%(Filename)%(Extension)" />
-    <Content Include="..\..\integrations.json"
-             CopyToOutputDirectory="Always"
-             CopyToPublishDirectory="Always"
-             Link="profiler-lib\integrations.json" />
+    <None Include="..\..\src\Datadog.Trace.ClrProfiler.Native\bin\$(Configuration)\$(Platform)\**" CopyToOutputDirectory="Always" CopyToPublishDirectory="Always" Link="profiler-lib\%(RecursiveDir)\%(Filename)%(Extension)" />
+    <Content Include="..\..\integrations.json" CopyToOutputDirectory="Always" CopyToPublishDirectory="Always" Link="profiler-lib\integrations.json" />
   </ItemGroup>
 
   <ItemGroup>
@@ -24,4 +18,6 @@
   <ItemGroup>
     <PackageReference Include="Newtonsoft.Json" Version="12.0.1" />
   </ItemGroup>
+
+  <ProjectExtensions><VisualStudio><UserProperties _1_1_4_1_1_4integrations_1json__JsonSchema="http://json.schemastore.org/ansible-stable-2.7" /></VisualStudio></ProjectExtensions>
 </Project>
diff --git a/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs b/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
index 97771196e6f0..de3c4367080e 100644
--- a/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
+++ b/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
@@ -38,7 +38,19 @@ public static IEnumerable<object[]> GetTestData()
 
             yield return new object[] { ConfigurationKeys.DisabledIntegrations, "integration1;integration2", CreateFunc(s => s.DisabledIntegrationNames.Count), 2 };
 
-            yield return new object[] { ConfigurationKeys.GlobalTags, "'k1':'v1', 'k2':'v2'", CreateFunc(s => s.GlobalTags.Count), 2 };
+            yield return new object[] { ConfigurationKeys.GlobalTags, "k1:v1, k2:v2", CreateFunc(s => s.GlobalTags.Count), 2 };
+        }
+
+        // JsonConfigurationSource needs to be tested with JSON data, which cannot be used with the other IConfigurationSource implementations.
+        public static IEnumerable<object[]> GetJsonTestData()
+        {
+            yield return new object[] { ConfigurationKeys.GlobalTags, @"{ ""name1"":""value1"", ""name2"": ""value2""}", CreateFunc(s => s.GlobalTags.Count), 2 };
+        }
+
+        public static IEnumerable<object[]> GetBadJsonTestData()
+        {
+            // Extra opening brace
+            yield return new object[] { ConfigurationKeys.GlobalTags, @"{ {""name1"":""value1"", ""name2"": ""value2""}" };
         }
 
         public static Func<TracerSettings, object> CreateFunc(Func<TracerSettings, object> settingGetter)
@@ -93,7 +105,8 @@ public void EnvironmentConfigurationSource(
 
         [Theory]
         [MemberData(nameof(GetTestData))]
-        public void NameValueConfigurationSource1(
+        [MemberData(nameof(GetJsonTestData))]
+        public void JsonConfigurationSource(
             string key,
             string value,
             Func<TracerSettings, object> settingGetter,
@@ -107,5 +120,18 @@ public void NameValueConfigurationSource1(
             object actualValue = settingGetter(settings);
             Assert.Equal(expectedValue, actualValue);
         }
+
+        [Theory]
+        [MemberData(nameof(GetBadJsonTestData))]
+        public void JsonConfigurationSource_BadData(
+            string key,
+            string value)
+        {
+            var config = new Dictionary<string, string> { [key] = value };
+            string json = JsonConvert.SerializeObject(config);
+            IConfigurationSource source = new JsonConfigurationSource(json);
+
+            Assert.Throws<JsonReaderException>(() => { new TracerSettings(source); });
+        }
     }
 }

From 0879026f587d4f62a8b071f32ec6a053f316ca6d Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Fri, 25 Oct 2019 08:22:48 -0700
Subject: [PATCH 08/13] Remove unused file

---
 .../CsvMapConfigurationSource.cs              | 60 -------------------
 1 file changed, 60 deletions(-)
 delete mode 100644 src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs

diff --git a/src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs b/src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs
deleted file mode 100644
index d2b548b8ecdc..000000000000
--- a/src/Datadog.Trace/Configuration/CsvMapConfigurationSource.cs
+++ /dev/null
@@ -1,60 +0,0 @@
-using System;
-using System.Collections.Concurrent;
-
-namespace Datadog.Trace.Configuration
-{
-    /// <summary>
-    /// Represents a configuration source that retrieves values from
-    /// a comma-separate list of key-value pairs.
-    /// </summary>
-    public class CsvMapConfigurationSource : StringConfigurationSource
-    {
-        private ConcurrentDictionary<string, string> _data;
-
-        /// <summary>
-        /// Initializes a new instance of the <see cref="CsvMapConfigurationSource"/> class
-        /// using a custom configuration string format.
-        /// </summary>
-        /// <param name="config">Configuration string that is a comma-separated list of key, value pairs where key and value are colon-separated.</param>
-        /// <example>An example configuration string would be "'globalTag1':'someValue','globalTag2':'anotherValue'"</example>
-        public CsvMapConfigurationSource(string config)
-        {
-            _data = ParseConfig(config);
-        }
-
-        /// <summary>
-        /// Gets the configuration data as a <see cref="ConcurrentDictionary{TKey, TValue}"/>
-        /// </summary>
-        public ConcurrentDictionary<string, string> Data
-        {
-            get { return _data; }
-        }
-
-        /// <inheritdoc />
-        public override string GetString(string key)
-        {
-            throw new NotImplementedException();
-        }
-
-        private ConcurrentDictionary<string, string> ParseConfig(string config)
-        {
-            var data = new ConcurrentDictionary<string, string>();
-
-            var entries = config.Split(',');
-            foreach (var e in entries)
-            {
-                var kv = e.Split(':');
-                if (kv.Length != 2)
-                {
-                    continue;
-                }
-
-                var key = kv[0];
-                var value = kv[1];
-                data[key] = value;
-            }
-
-            return data;
-        }
-    }
-}

From 2f4048f97b7819da874da6f00de217b53e85e82f Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Fri, 25 Oct 2019 08:32:29 -0700
Subject: [PATCH 09/13] Spacing fix

---
 .../Configuration/EnvironmentConfigurationSource.cs             | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Datadog.Trace/Configuration/EnvironmentConfigurationSource.cs b/src/Datadog.Trace/Configuration/EnvironmentConfigurationSource.cs
index 21e5d193c807..016bc22af7a7 100644
--- a/src/Datadog.Trace/Configuration/EnvironmentConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/EnvironmentConfigurationSource.cs
@@ -13,5 +13,5 @@ public override string GetString(string key)
         {
             return Environment.GetEnvironmentVariable(key);
         }
-   }
+    }
 }

From d8de2f2d9b0b9fd409500f5af44c0ec547e64a78 Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Fri, 25 Oct 2019 11:11:10 -0700
Subject: [PATCH 10/13] Improved JsonConfigurationSource tests

---
 .../Configuration/JsonConfigurationSource.cs  |  2 +-
 .../StringConfigurationSource.cs              |  2 +-
 .../Configuration/TracerSettings.cs           |  4 +-
 .../Configuration/ConfigurationSourceTests.cs | 37 +++++++++++--------
 4 files changed, 25 insertions(+), 20 deletions(-)

diff --git a/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs b/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
index 5ec3e79f0401..e7f4ee783a0a 100644
--- a/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
@@ -125,7 +125,7 @@ public IDictionary<string, string> GetDictionary(string key)
 
             // Presence of a curly brace indicates that this is likely a JSON string. An exception will be thrown
             // if it fails to parse or convert to a dictionary.
-            if (token.ToString().Contains("{"))
+            if (token.Type == JTokenType.Object)
             {
                 var dictionary = JToken.Parse(token.ToString())
                     ?.ToObject(typeof(ConcurrentDictionary<string, string>)) as ConcurrentDictionary<string, string>;
diff --git a/src/Datadog.Trace/Configuration/StringConfigurationSource.cs b/src/Datadog.Trace/Configuration/StringConfigurationSource.cs
index e4d3075d9e19..6ffed4034d2e 100644
--- a/src/Datadog.Trace/Configuration/StringConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/StringConfigurationSource.cs
@@ -19,7 +19,7 @@ public static IDictionary<string, string> ParseCustomKeyValues(string data)
         {
             var dictionary = new ConcurrentDictionary<string, string>();
 
-            if (data == null)
+            if (string.IsNullOrWhiteSpace(data))
             {
                 return dictionary;
             }
diff --git a/src/Datadog.Trace/Configuration/TracerSettings.cs b/src/Datadog.Trace/Configuration/TracerSettings.cs
index 04c749c0352b..f9dced94ecc0 100644
--- a/src/Datadog.Trace/Configuration/TracerSettings.cs
+++ b/src/Datadog.Trace/Configuration/TracerSettings.cs
@@ -79,7 +79,7 @@ public TracerSettings(IConfigurationSource source)
 
             Integrations = new IntegrationSettingsCollection(source);
 
-            GlobalTags = source?.GetDictionary(ConfigurationKeys.GlobalTags) as ConcurrentDictionary<string, string> ??
+            GlobalTags = source?.GetDictionary(ConfigurationKeys.GlobalTags) as IDictionary<string, string> ??
                 new ConcurrentDictionary<string, string>();
         }
 
@@ -149,7 +149,7 @@ public TracerSettings(IConfigurationSource source)
         /// <summary>
         /// Gets or sets the global tags, which are applied to all <see cref="Span"/>s.
         /// </summary>
-        public ConcurrentDictionary<string, string> GlobalTags { get; set; }
+        public IDictionary<string, string> GlobalTags { get; set; }
 
         /// <summary>
         /// Create a <see cref="TracerSettings"/> populated from the default sources
diff --git a/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs b/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
index de3c4367080e..79aa93f55b34 100644
--- a/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
+++ b/test/Datadog.Trace.Tests/Configuration/ConfigurationSourceTests.cs
@@ -44,13 +44,19 @@ public static IEnumerable<object[]> GetTestData()
         // JsonConfigurationSource needs to be tested with JSON data, which cannot be used with the other IConfigurationSource implementations.
         public static IEnumerable<object[]> GetJsonTestData()
         {
-            yield return new object[] { ConfigurationKeys.GlobalTags, @"{ ""name1"":""value1"", ""name2"": ""value2""}", CreateFunc(s => s.GlobalTags.Count), 2 };
+            yield return new object[] { @"{ ""DD_TRACE_GLOBAL_TAGS"": { ""name1"":""value1"", ""name2"": ""value2""} }", CreateFunc(s => s.GlobalTags.Count), 2 };
         }
 
-        public static IEnumerable<object[]> GetBadJsonTestData()
+        public static IEnumerable<object[]> GetBadJsonTestData1()
         {
             // Extra opening brace
-            yield return new object[] { ConfigurationKeys.GlobalTags, @"{ {""name1"":""value1"", ""name2"": ""value2""}" };
+            yield return new object[] { @"{ ""DD_TRACE_GLOBAL_TAGS"": { { ""name1"":""value1"", ""name2"": ""value2""} }" };
+        }
+
+        public static IEnumerable<object[]> GetBadJsonTestData2()
+        {
+            // Missing closing brace
+            yield return new object[] { @"{ ""DD_TRACE_GLOBAL_TAGS"": { ""name1"":""value1"", ""name2"": ""value2"" }" };
         }
 
         public static Func<TracerSettings, object> CreateFunc(Func<TracerSettings, object> settingGetter)
@@ -104,34 +110,33 @@ public void EnvironmentConfigurationSource(
         }
 
         [Theory]
-        [MemberData(nameof(GetTestData))]
         [MemberData(nameof(GetJsonTestData))]
         public void JsonConfigurationSource(
-            string key,
             string value,
             Func<TracerSettings, object> settingGetter,
             object expectedValue)
         {
-            var config = new Dictionary<string, string> { [key] = value };
-            string json = JsonConvert.SerializeObject(config);
-            IConfigurationSource source = new JsonConfigurationSource(json);
+            IConfigurationSource source = new JsonConfigurationSource(value);
             var settings = new TracerSettings(source);
 
-            object actualValue = settingGetter(settings);
+            var actualValue = settingGetter(settings);
             Assert.Equal(expectedValue, actualValue);
         }
 
         [Theory]
-        [MemberData(nameof(GetBadJsonTestData))]
-        public void JsonConfigurationSource_BadData(
-            string key,
+        [MemberData(nameof(GetBadJsonTestData1))]
+        public void JsonConfigurationSource_BadData1(
             string value)
         {
-            var config = new Dictionary<string, string> { [key] = value };
-            string json = JsonConvert.SerializeObject(config);
-            IConfigurationSource source = new JsonConfigurationSource(json);
+            Assert.Throws<JsonReaderException>(() => { new JsonConfigurationSource(value); });
+        }
 
-            Assert.Throws<JsonReaderException>(() => { new TracerSettings(source); });
+        [Theory]
+        [MemberData(nameof(GetBadJsonTestData2))]
+        public void JsonConfigurationSource_BadData2(
+            string value)
+        {
+            Assert.Throws<JsonSerializationException>(() => { new JsonConfigurationSource(value); });
         }
     }
 }

From bdb7126dce6996656e60963db88591ce6f699f5d Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Fri, 25 Oct 2019 12:55:43 -0700
Subject: [PATCH 11/13] Use generic ToObject

---
 src/Datadog.Trace/Configuration/JsonConfigurationSource.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs b/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
index e7f4ee783a0a..bc68d5538dd6 100644
--- a/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
@@ -128,7 +128,7 @@ public IDictionary<string, string> GetDictionary(string key)
             if (token.Type == JTokenType.Object)
             {
                 var dictionary = JToken.Parse(token.ToString())
-                    ?.ToObject(typeof(ConcurrentDictionary<string, string>)) as ConcurrentDictionary<string, string>;
+                    ?.ToObject<ConcurrentDictionary<string, string>>() as ConcurrentDictionary<string, string>;
                 return dictionary;
             }
 

From b08499e550e26ad8ada6dd0407a8530ca67c9576 Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Fri, 25 Oct 2019 13:49:02 -0700
Subject: [PATCH 12/13] Revert
 Datadog.Trace.ClrProfiler.IntegrationTests.csproj change

---
 ...Datadog.Trace.ClrProfiler.IntegrationTests.csproj | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/test/Datadog.Trace.ClrProfiler.IntegrationTests/Datadog.Trace.ClrProfiler.IntegrationTests.csproj b/test/Datadog.Trace.ClrProfiler.IntegrationTests/Datadog.Trace.ClrProfiler.IntegrationTests.csproj
index a30c20310a1b..27fbd33f27c6 100644
--- a/test/Datadog.Trace.ClrProfiler.IntegrationTests/Datadog.Trace.ClrProfiler.IntegrationTests.csproj
+++ b/test/Datadog.Trace.ClrProfiler.IntegrationTests/Datadog.Trace.ClrProfiler.IntegrationTests.csproj
@@ -6,8 +6,14 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <None Include="..\..\src\Datadog.Trace.ClrProfiler.Native\bin\$(Configuration)\$(Platform)\**" CopyToOutputDirectory="Always" CopyToPublishDirectory="Always" Link="profiler-lib\%(RecursiveDir)\%(Filename)%(Extension)" />
-    <Content Include="..\..\integrations.json" CopyToOutputDirectory="Always" CopyToPublishDirectory="Always" Link="profiler-lib\integrations.json" />
+    <None Include="..\..\src\Datadog.Trace.ClrProfiler.Native\bin\$(Configuration)\$(Platform)\**"
+             CopyToOutputDirectory="Always"
+             CopyToPublishDirectory="Always"
+             Link="profiler-lib\%(RecursiveDir)\%(Filename)%(Extension)" />
+    <Content Include="..\..\integrations.json"
+             CopyToOutputDirectory="Always"
+             CopyToPublishDirectory="Always"
+             Link="profiler-lib\integrations.json" />
   </ItemGroup>
 
   <ItemGroup>
@@ -18,6 +24,4 @@
   <ItemGroup>
     <PackageReference Include="Newtonsoft.Json" Version="12.0.1" />
   </ItemGroup>
-
-  <ProjectExtensions><VisualStudio><UserProperties _1_1_4_1_1_4integrations_1json__JsonSchema="http://json.schemastore.org/ansible-stable-2.7" /></VisualStudio></ProjectExtensions>
 </Project>

From 6812e7b578a1b482072a741910c742f5efbe07be Mon Sep 17 00:00:00 2001
From: Bob Uva <robertuva@gmail.com>
Date: Fri, 25 Oct 2019 16:05:09 -0700
Subject: [PATCH 13/13] More changes per code review

---
 .../Configuration/JsonConfigurationSource.cs              | 2 +-
 .../Configuration/StringConfigurationSource.cs            | 8 ++++++++
 src/Datadog.Trace/Configuration/TracerSettings.cs         | 2 +-
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs b/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
index bc68d5538dd6..64c3d2adb6c7 100644
--- a/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/JsonConfigurationSource.cs
@@ -127,7 +127,7 @@ public IDictionary<string, string> GetDictionary(string key)
             // if it fails to parse or convert to a dictionary.
             if (token.Type == JTokenType.Object)
             {
-                var dictionary = JToken.Parse(token.ToString())
+                var dictionary = token
                     ?.ToObject<ConcurrentDictionary<string, string>>() as ConcurrentDictionary<string, string>;
                 return dictionary;
             }
diff --git a/src/Datadog.Trace/Configuration/StringConfigurationSource.cs b/src/Datadog.Trace/Configuration/StringConfigurationSource.cs
index 6ffed4034d2e..7c9dca3ec608 100644
--- a/src/Datadog.Trace/Configuration/StringConfigurationSource.cs
+++ b/src/Datadog.Trace/Configuration/StringConfigurationSource.cs
@@ -19,6 +19,14 @@ public static IDictionary<string, string> ParseCustomKeyValues(string data)
         {
             var dictionary = new ConcurrentDictionary<string, string>();
 
+            // A null return value means the key was not present,
+            // and CompositeConfigurationSource depends on this behavior
+            // (it returns the first non-null value it finds).
+            if (data == null)
+            {
+                return null;
+            }
+
             if (string.IsNullOrWhiteSpace(data))
             {
                 return dictionary;
diff --git a/src/Datadog.Trace/Configuration/TracerSettings.cs b/src/Datadog.Trace/Configuration/TracerSettings.cs
index f9dced94ecc0..a7e8849e04ae 100644
--- a/src/Datadog.Trace/Configuration/TracerSettings.cs
+++ b/src/Datadog.Trace/Configuration/TracerSettings.cs
@@ -79,7 +79,7 @@ public TracerSettings(IConfigurationSource source)
 
             Integrations = new IntegrationSettingsCollection(source);
 
-            GlobalTags = source?.GetDictionary(ConfigurationKeys.GlobalTags) as IDictionary<string, string> ??
+            GlobalTags = source?.GetDictionary(ConfigurationKeys.GlobalTags) ??
                 new ConcurrentDictionary<string, string>();
         }