Adding method to EvictingQueue, updating SpanSdk to update if key exists (#557)

* Adding method to EvictingQueue, updating SpanSdk to update if key exists

* Adding Replacing test to EvictingQueue; Updating SpanTest; Renaming from Update to Replace

* Adding wrapper to AddOrUpdateAttribute, adding validation to index in Replace method

* Adding NoReplacing Test when element doesn't exist

Co-authored-by: Sergey Kanzhelev <S.Kanzhelev@live.com>

src/OpenTelemetry/Trace/Internal/EvictingQueue.cs

@@ -59,6 +59,21 @@ namespace OpenTelemetry.Trace.Internal
             return new Enumerator(this);
         }
 
+        internal void Replace(T item, T newItem)
+        {
+            Debug.Assert(item != null, "Item must not be null");
+            Debug.Assert(newItem != null, "Item must not be null");
+
+            var index = Array.IndexOf(this.items, item);
+
+            if (index < 0)
+            {
+                return;
+            }
+
+            this.items[index] = newItem;
+        }
+
         internal void Add(T item)
         {
             Debug.Assert(item != null, "Item must not be null");

src/OpenTelemetry/Trace/SpanSdk.cs

@@ -333,7 +333,7 @@ namespace OpenTelemetry.Trace
                         new EvictingQueue<KeyValuePair<string, object>>(this.tracerConfiguration.MaxNumberOfAttributes);
                 }
 
-                this.attributes.Add(new KeyValuePair<string, object>(key ?? string.Empty, sanitizedValue));
+                this.AddOrReplaceAttribute(key, sanitizedValue);
             }
         }
 
@@ -359,7 +359,7 @@ namespace OpenTelemetry.Trace
                         new EvictingQueue<KeyValuePair<string, object>>(this.tracerConfiguration.MaxNumberOfAttributes);
                 }
 
-                this.attributes.Add(new KeyValuePair<string, object>(key ?? string.Empty, value));
+                this.AddOrReplaceAttribute(key, value);
             }
         }
 
@@ -385,7 +385,7 @@ namespace OpenTelemetry.Trace
                         new EvictingQueue<KeyValuePair<string, object>>(this.tracerConfiguration.MaxNumberOfAttributes);
                 }
 
-                this.attributes.Add(new KeyValuePair<string, object>(key ?? string.Empty, value));
+                this.AddOrReplaceAttribute(key, value);
             }
         }
 
@@ -411,7 +411,7 @@ namespace OpenTelemetry.Trace
                         new EvictingQueue<KeyValuePair<string, object>>(this.tracerConfiguration.MaxNumberOfAttributes);
                 }
 
-                this.attributes.Add(new KeyValuePair<string, object>(key ?? string.Empty, value));
+                this.AddOrReplaceAttribute(key, value);
             }
         }
 
@@ -878,6 +878,20 @@ namespace OpenTelemetry.Trace
                    || attributeValue is decimal;
         }
 
+        private void AddOrReplaceAttribute(string key, object value)
+        {
+            var attribute = this.attributes.FirstOrDefault(a => a.Key == (key ?? string.Empty));
+            var newAttribute = new KeyValuePair<string, object>(key ?? string.Empty, value);
+            if (attribute.Equals(default(KeyValuePair<string, object>)))
+            {
+                this.attributes.Add(newAttribute);
+            }
+            else
+            {
+                this.attributes.Replace(attribute, newAttribute);
+            }
+        }
+
         private readonly struct ActivityAndTracestate
         {
             public readonly Activity Activity;

test/OpenTelemetry.Tests/EvictingQueueTests.cs

@@ -86,5 +86,27 @@ namespace OpenTelemetry.Tests
 
             Assert.Empty(eq);
         }
+
+        [Fact]
+        public void Replacing()
+        {
+            var eq = new EvictingQueue<int>(1) { 0 };
+            eq.Replace(0, 1);
+
+            var items = eq.ToArray();
+
+            Assert.Equal(1, items[0]);
+        }
+
+        [Fact]
+        public void NoReplacing()
+        {
+            var eq = new EvictingQueue<int>(1) { 0 };
+            eq.Replace(1, 1);
+
+            var items = eq.ToArray();
+
+            Assert.Equal(0, items[0]);
+        }
     }
 }

test/OpenTelemetry.Tests/Impl/Trace/SpanTest.cs

@@ -978,10 +978,7 @@ namespace OpenTelemetry.Trace.Test
             span.SetAttribute(null, 0.1d);
             span.SetAttribute(null, false);
 
-            Assert.Equal(4, span.Attributes.Count());
-            Assert.Single(span.Attributes.Where(kvp => kvp.Key == string.Empty && kvp.Value is long lv && lv  == 1L));
-            Assert.Single(span.Attributes.Where(kvp => kvp.Key == string.Empty && kvp.Value is double dv && dv == 0.1d));
-            Assert.Single(span.Attributes.Where(kvp => kvp.Key == string.Empty && kvp.Value is string sv && sv == "foo"));
+            Assert.Single(span.Attributes);
             Assert.Single(span.Attributes.Where(kvp => kvp.Key == string.Empty && kvp.Value is bool bv && bv == false));
         }