[AzureMonitorExporter] Fix Culture-Specific Formatting of Activity Tags

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/CHANGELOG.md

@@ -40,6 +40,16 @@
      * In case of duplicate keys within the scopes, only the first entry is
      retained, while all subsequent duplicate entries are discarded.
 
+* Resolved an issue where activity tags of various object types, including
+  double, float, and others, were previously formatted using
+  `CultureInfo.CurrentCulture`. This behavior caused inconsistencies in tag
+  value formatting depending on the regional settings of the machine where the
+  application was running. Such inconsistencies could lead to challenges in data
+  analysis and cause test failures in environments with differing cultural
+  settings. The fix ensures uniform and culture-independent formatting of
+  activity tag values, aligning with consistent data representation.
+  ([#39470](https://github.com/Azure/azure-sdk-for-net/issues/39470))
+
 ### Other Changes
 
 * Update OpenTelemetry dependencies

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/src/Internals/ArrayExtensions.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT License.
 
 using System;
+using System.Globalization;
 using System.Text;
 
 namespace Azure.Monitor.OpenTelemetry.Exporter.Internals
@@ -18,6 +19,12 @@ internal static class ArrayExtensions
         /// <returns>A comma delimited string of the components of the input array.</returns>
         [return: System.Diagnostics.CodeAnalysis.NotNullIfNotNull(nameof(input))]
         public static string? ToCommaDelimitedString(this Array? input)
+        {
+            return ToCommaDelimitedString(input, CultureInfo.InvariantCulture);
+        }
+
+        // This overload is used for testing purposes only.
+        internal static string? ToCommaDelimitedString(this Array? input, CultureInfo cultureInfo)
         {
             if (input == null)
             {
@@ -29,7 +36,7 @@ internal static class ArrayExtensions
             {
                 if (item != null)
                 {
-                    sb.Append(item);
+                    sb.Append(Convert.ToString(item, cultureInfo));
                     sb.Append(',');
                 }
             }

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/src/Internals/TraceHelper.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Globalization;
 using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Text;
@@ -85,7 +86,7 @@ internal static void AddPropertiesToTelemetry(IDictionary<string, string> destin
                 {
                     // Note: if Key exceeds MaxLength or if Value is null, the entire KVP will be dropped.
 
-                    destination.Add(tag.Key, tag.Value.ToString().Truncate(SchemaConstants.KVP_MaxValueLength) ?? "null");
+                    destination.Add(tag.Key, Convert.ToString(tag.Value, CultureInfo.InvariantCulture).Truncate(SchemaConstants.KVP_MaxValueLength) ?? "null");
                 }
             }
         }

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/tests/Azure.Monitor.OpenTelemetry.Exporter.Tests/TagsTests.cs

@@ -4,7 +4,8 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
-
+using System.Globalization;
+using System.Threading;
 using Azure.Monitor.OpenTelemetry.Exporter.Internals;
 
 using Xunit;
@@ -81,7 +82,7 @@ public void TagObjects_UnMapped()
         {
             var activityTagsProcessor = new ActivityTagsProcessor();
 
-            IEnumerable<KeyValuePair<string, object?>> tagObjects = new Dictionary<string, object?> { ["somekey"] = "value" }; ;
+            IEnumerable<KeyValuePair<string, object?>> tagObjects = new Dictionary<string, object?> { ["somekey"] = "value" };
             using var activity = CreateTestActivity(tagObjects);
             activityTagsProcessor.CategorizeTags(activity);
 
@@ -344,6 +345,42 @@ public void ActivityTagsProcessor_CategorizeTags_ExtractsAuthUserId(ActivityKind
             Assert.Equal("TestUser", activityTagsProcessor.EndUserId);
         }
 
+        [Theory]
+        [InlineData("fr-FR")] // French culture
+        [InlineData("de-DE")] // German culture
+        public void TagObjects_TestCulture(string cultureName)
+        {
+            var activityTagsProcessor = new ActivityTagsProcessor();
+            var originalCulture = Thread.CurrentThread.CurrentCulture;
+            var cultureInfo = new CultureInfo(cultureName);
+            Thread.CurrentThread.CurrentCulture = cultureInfo;
+            IDictionary<string, string> properties = new Dictionary<string, string>();
+
+            var doubleArray = new double[] { 1.1, 2.2, 3.3 };
+            var doubleValue = 123.45;
+
+            IEnumerable<KeyValuePair<string, object?>> tagObjects = new Dictionary<string, object?>
+            {
+                ["doubleArray"] = doubleArray,
+                ["double"] = doubleValue,
+            };
+
+            using var activity = CreateTestActivity(tagObjects);
+            activityTagsProcessor.CategorizeTags(activity);
+            TraceHelper.AddPropertiesToTelemetry(properties, ref activityTagsProcessor.UnMappedTags);
+
+            // Asserting Culture Behavior
+            Assert.NotEqual("1.1,2.2,3.3", doubleArray.ToCommaDelimitedString(cultureInfo));
+            Assert.NotEqual("123.45", doubleValue.ToString(cultureInfo));
+
+            // Asserting CultureInvariant Behavior
+            Assert.Equal("1.1,2.2,3.3", properties["doubleArray"]);
+            Assert.Equal("123.45", properties["double"]);
+
+            // Cleanup: Revert to the original culture
+            Thread.CurrentThread.CurrentCulture = originalCulture;
+        }
+
         private static Activity CreateTestActivity(IEnumerable<KeyValuePair<string, object?>>? additionalAttributes = null, ActivityKind activityKind = ActivityKind.Server)
         {
             var startTimestamp = DateTime.UtcNow;