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rajkumar-rangaraj merged 4 commits into from
Nov 13, 2025
Merged

[AzureMonitorExporter] Trace based logs sampler #53441

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783b521
Trace based logs sampler
rajkumar-rangaraj Oct 23, 2025
b3098e3
Public api summary, test fix, api update and changelog
rajkumar-rangaraj Nov 12, 2025
60cfdce
missed changelog
rajkumar-rangaraj Nov 12, 2025
d8d0788
resolve conflicts
rajkumar-rangaraj Nov 12, 2025
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5 changes: 5 additions & 0 deletions sdk/monitor/Azure.Monitor.OpenTelemetry.AspNetCore/CHANGELOG.md
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Expand Up @@ -4,6 +4,11 @@

### Features Added

* Added `EnableTraceBasedLogSampler` property to `AzureMonitorOptions` to enable
filtering logs based on trace sampling decisions, reducing log volume while
maintaining trace-log correlation.
([#53441](https://github.com/Azure/azure-sdk-for-net/pull/53441))

### Breaking Changes

### Bugs Fixed
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1 change: 1 addition & 0 deletions ...ure.Monitor.OpenTelemetry.AspNetCore/api/Azure.Monitor.OpenTelemetry.AspNetCore.net8.0.cs
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Expand Up @@ -7,6 +7,7 @@ public AzureMonitorOptions() { }
public Azure.Core.TokenCredential Credential { get { throw null; } set { } }
public bool DisableOfflineStorage { get { throw null; } set { } }
public bool EnableLiveMetrics { get { throw null; } set { } }
public bool EnableTraceBasedLogsSampler { get { throw null; } set { } }
public float SamplingRatio { get { throw null; } set { } }
public string StorageDirectory { get { throw null; } set { } }
public double? TracesPerSecond { get { throw null; } set { } }
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1 change: 1 addition & 0 deletions ...tor.OpenTelemetry.AspNetCore/api/Azure.Monitor.OpenTelemetry.AspNetCore.netstandard2.0.cs
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Expand Up @@ -7,6 +7,7 @@ public AzureMonitorOptions() { }
public Azure.Core.TokenCredential Credential { get { throw null; } set { } }
public bool DisableOfflineStorage { get { throw null; } set { } }
public bool EnableLiveMetrics { get { throw null; } set { } }
public bool EnableTraceBasedLogsSampler { get { throw null; } set { } }
public float SamplingRatio { get { throw null; } set { } }
public string StorageDirectory { get { throw null; } set { } }
public double? TracesPerSecond { get { throw null; } set { } }
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6 changes: 3 additions & 3 deletions .../Azure.Monitor.OpenTelemetry.AspNetCore/src/Azure.Monitor.OpenTelemetry.AspNetCore.csproj
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@@ -1,4 +1,4 @@
<Project Sdk="Microsoft.NET.Sdk">
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<Description>An OpenTelemetry .NET distro that exports to Azure Monitor</Description>
<AssemblyTitle>AzureMonitor OpenTelemetry ASP.NET Core Distro</AssemblyTitle>
Expand All @@ -24,10 +24,10 @@
<!-- Depending on monthly deliverables, we may switch between PackageReference or ProjectReference. Keeping both here to make the switch easier. -->

<!-- FOR PUBLIC RELEASES, MUST USE PackageReference. THIS REQUIRES A STAGGERED RELEASE IF SHIPPING A NEW EXPORTER. -->
<PackageReference Include="Azure.Monitor.OpenTelemetry.Exporter" VersionOverride="1.5.0-beta.1" />
<!--<PackageReference Include="Azure.Monitor.OpenTelemetry.Exporter" VersionOverride="1.5.0-beta.1" />-->

<!-- FOR LOCAL DEV, ProjectReference IS PREFERRED. -->
<!--<ProjectReference Include="..\..\Azure.Monitor.OpenTelemetry.Exporter\src\Azure.Monitor.OpenTelemetry.Exporter.csproj" />-->
<ProjectReference Include="..\..\Azure.Monitor.OpenTelemetry.Exporter\src\Azure.Monitor.OpenTelemetry.Exporter.csproj" />
</ItemGroup>

<!-- Shared sources from Azure.Core -->
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26 changes: 11 additions & 15 deletions sdk/monitor/Azure.Monitor.OpenTelemetry.AspNetCore/src/AzureMonitorOptions.cs
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Expand Up @@ -48,6 +48,16 @@ public class AzureMonitorOptions : ClientOptions
/// </summary>
public bool EnableLiveMetrics { get; set; } = true;

/// <summary>
/// Enables or disables filtering logs based on trace sampling decisions.
/// </summary>
/// <remarks>
/// When enabled, only logs associated with sampled traces are exported.
/// Logs without trace context are always exported.
/// This reduces log volume while maintaining trace-log correlation.
/// </remarks>
public bool EnableTraceBasedLogsSampler { get; set; } = true;

/// <summary>
/// Gets or sets the ratio of telemetry items to be sampled. The value must be between 0.0F and 1.0F, inclusive.
/// For example, specifying 0.4 means that 40% of traces are sampled and 60% are dropped.
Expand Down Expand Up @@ -86,27 +96,13 @@ internal void SetValueToExporterOptions(AzureMonitorExporterOptions exporterOpti
exporterOptions.TracesPerSecond = TracesPerSecond;
exporterOptions.StorageDirectory = StorageDirectory;
exporterOptions.EnableLiveMetrics = EnableLiveMetrics;
exporterOptions.EnableTraceBasedLogsSampler = EnableTraceBasedLogsSampler;
if (Transport != null)
{
exporterOptions.Transport = Transport;
}
exporterOptions.Diagnostics.IsDistributedTracingEnabled = Diagnostics.IsDistributedTracingEnabled;
exporterOptions.Diagnostics.IsLoggingEnabled = Diagnostics.IsLoggingEnabled;
}

//internal void SetValueToLiveMetricsOptions(AzureMonitorLiveMetricsOptions liveMetricsOptions)
//{
// liveMetricsOptions.ConnectionString = ConnectionString;
// liveMetricsOptions.Credential = Credential;
// liveMetricsOptions.EnableLiveMetrics = EnableLiveMetrics;

// if (Transport != null)
// {
// liveMetricsOptions.Transport = Transport;
// }

// liveMetricsOptions.Diagnostics.IsDistributedTracingEnabled = Diagnostics.IsDistributedTracingEnabled;
// liveMetricsOptions.Diagnostics.IsLoggingEnabled = Diagnostics.IsLoggingEnabled;
//}
}
}
174 changes: 174 additions & 0 deletions ...AspNetCore/tests/Azure.Monitor.OpenTelemetry.AspNetCore.Tests/AzureMonitorOptionsTests.cs
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@@ -0,0 +1,174 @@
// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.

using System;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using Azure.Monitor.OpenTelemetry.Exporter;
using Xunit;

namespace Azure.Monitor.OpenTelemetry.AspNetCore.Tests
{
public class AzureMonitorOptionsTests
{
private const string TestConnectionString = "InstrumentationKey=00000000-0000-0000-0000-000000000000";

[Fact]
public void AzureMonitorOptions_EnableTraceBasedLogsSampler_DefaultValue_IsTrue()
{
// Arrange & Act
var options = new AzureMonitorOptions();

// Assert
Assert.True(options.EnableTraceBasedLogsSampler);
}

[Fact]
public void AzureMonitorOptions_EnableTraceBasedLogsSampler_CanBeDisabled()
{
// Arrange & Act
var options = new AzureMonitorOptions
{
EnableTraceBasedLogsSampler = false
};

// Assert
Assert.False(options.EnableTraceBasedLogsSampler);
}

[Fact]
public void AzureMonitorOptions_SetValueToExporterOptions_CopiesEnableTraceBasedLogsSampler()
{
// Arrange
var azureMonitorOptions = new AzureMonitorOptions
{
ConnectionString = TestConnectionString,
EnableTraceBasedLogsSampler = false
};

var exporterOptions = new AzureMonitorExporterOptions();

// Act
azureMonitorOptions.SetValueToExporterOptions(exporterOptions);

// Assert
Assert.False(exporterOptions.EnableTraceBasedLogsSampler);
Assert.Equal(TestConnectionString, exporterOptions.ConnectionString);
}

[Fact]
public void UseAzureMonitor_DefaultEnableTraceBasedLogsSampler()
{
// Arrange
var serviceCollection = new ServiceCollection();

// Act
serviceCollection.AddOpenTelemetry()
.UseAzureMonitor(options =>
{
options.ConnectionString = TestConnectionString;
options.DisableOfflineStorage = true;
});

var serviceProvider = serviceCollection.BuildServiceProvider();

// Assert
var azureMonitorOptions = serviceProvider.GetRequiredService<IOptionsMonitor<AzureMonitorOptions>>()
.Get(Options.DefaultName);

Assert.True(azureMonitorOptions.EnableTraceBasedLogsSampler);

var exporterOptions = serviceProvider.GetRequiredService<IOptionsMonitor<AzureMonitorExporterOptions>>()
.Get(Options.DefaultName);

Assert.True(exporterOptions.EnableTraceBasedLogsSampler);
}

[Fact]
public void UseAzureMonitor_CanDisableTraceBasedLogsSampler()
{
// Arrange
var serviceCollection = new ServiceCollection();

// Act
serviceCollection.AddOpenTelemetry()
.UseAzureMonitor(options =>
{
options.ConnectionString = TestConnectionString;
options.EnableTraceBasedLogsSampler = false;
options.DisableOfflineStorage = true;
});

var serviceProvider = serviceCollection.BuildServiceProvider();

// Assert
var azureMonitorOptions = serviceProvider.GetRequiredService<IOptionsMonitor<AzureMonitorOptions>>()
.Get(Options.DefaultName);

Assert.False(azureMonitorOptions.EnableTraceBasedLogsSampler);

var exporterOptions = serviceProvider.GetRequiredService<IOptionsMonitor<AzureMonitorExporterOptions>>()
.Get(Options.DefaultName);

Assert.False(exporterOptions.EnableTraceBasedLogsSampler);
}

[Fact]
public void UseAzureMonitor_EnableTraceBasedLogsSampler_PropagatesCorrectly()
{
// Arrange
var serviceCollection = new ServiceCollection();

// Act - Test with true
serviceCollection.AddOpenTelemetry()
.UseAzureMonitor(options =>
{
options.ConnectionString = TestConnectionString;
options.EnableTraceBasedLogsSampler = true;
options.DisableOfflineStorage = true;
});

var serviceProvider = serviceCollection.BuildServiceProvider();

// Assert
var azureMonitorOptions = serviceProvider.GetRequiredService<IOptionsMonitor<AzureMonitorOptions>>()
.Get(Options.DefaultName);

var exporterOptions = serviceProvider.GetRequiredService<IOptionsMonitor<AzureMonitorExporterOptions>>()
.Get(Options.DefaultName);

Assert.Equal(azureMonitorOptions.EnableTraceBasedLogsSampler, exporterOptions.EnableTraceBasedLogsSampler);
Assert.True(exporterOptions.EnableTraceBasedLogsSampler);
}

[Fact]
public void UseAzureMonitor_WithoutConfiguration_UsesDefaultValue()
{
// Arrange
var serviceCollection = new ServiceCollection();

// Act
serviceCollection.AddOpenTelemetry()
.UseAzureMonitor(options =>
{
options.ConnectionString = TestConnectionString;
options.DisableOfflineStorage = true;

// Not setting EnableTraceBasedLogsSampler, should use default
});

var serviceProvider = serviceCollection.BuildServiceProvider();

// Assert
var azureMonitorOptions = serviceProvider.GetRequiredService<IOptionsMonitor<AzureMonitorOptions>>()
.Get(Options.DefaultName);

var exporterOptions = serviceProvider.GetRequiredService<IOptionsMonitor<AzureMonitorExporterOptions>>()
.Get(Options.DefaultName);

// Both should be true (default value)
Assert.True(azureMonitorOptions.EnableTraceBasedLogsSampler);
Assert.True(exporterOptions.EnableTraceBasedLogsSampler);
}
}
}
4 changes: 3 additions & 1 deletion ...ore/tests/Azure.Monitor.OpenTelemetry.AspNetCore.Tests/DefaultAzureMonitorOptionsTests.cs
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Expand Up @@ -29,6 +29,7 @@ public void VerifyConfigure_Default()
Assert.False(azureMonitorOptions.DisableOfflineStorage);
Assert.Equal(1.0F, azureMonitorOptions.SamplingRatio);
Assert.Null(azureMonitorOptions.StorageDirectory);
Assert.True(azureMonitorOptions.EnableTraceBasedLogsSampler);
}

#if NET
Expand All @@ -39,7 +40,8 @@ public void VerifyConfigure_ViaJson()
""ConnectionString"" : ""testJsonValue"",
""DisableOfflineStorage"" : ""true"",
""SamplingRatio"" : 0.5,
""StorageDirectory"" : ""testJsonValue""
""StorageDirectory"" : ""testJsonValue"",
""EnableTraceBasedLogsSampler"" : ""true""
}}";

var configuration = new ConfigurationBuilder()
Expand Down
4 changes: 0 additions & 4 deletions ...etry.AspNetCore/tests/Azure.Monitor.OpenTelemetry.AspNetCore.Tests/InitializationTests.cs
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Expand Up @@ -401,7 +401,6 @@ public static void EvaluateLoggerProvider(IServiceProvider serviceProvider, bool

var secondProcessor = valueField.GetValue(secondNode);
Assert.NotNull(secondProcessor);
Assert.Contains("BatchLogRecordExportProcessor", secondProcessor.GetType().Name);

var exporterProperty = secondProcessor.GetType().GetProperty("Exporter", BindingFlags.NonPublic | BindingFlags.Instance);
Assert.NotNull(exporterProperty);
Expand All @@ -412,9 +411,6 @@ public static void EvaluateLoggerProvider(IServiceProvider serviceProvider, bool
}
else
{
// When LiveMetrics is disabled, processor should be a BatchLogRecordExportProcessor
Assert.Contains("BatchLogRecordExportProcessor", processor.GetType().Name);

var exporterProperty = processor.GetType().GetProperty("Exporter", BindingFlags.NonPublic | BindingFlags.Instance);
Assert.NotNull(exporterProperty);

Expand Down
5 changes: 5 additions & 0 deletions sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/CHANGELOG.md
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Expand Up @@ -7,6 +7,11 @@
* Enabled resource metrics export by default.
([#53432](https://github.com/Azure/azure-sdk-for-net/pull/53432))

* Added `EnableTraceBasedLogSampler` property to `AzureMonitorExporterOptions`
to enable filtering logs based on trace sampling decisions, reducing log
volume while maintaining trace-log correlation.
([#53441](https://github.com/Azure/azure-sdk-for-net/pull/53441))

### Breaking Changes

### Bugs Fixed
Expand Down
1 change: 1 addition & 0 deletions ...r/Azure.Monitor.OpenTelemetry.Exporter/api/Azure.Monitor.OpenTelemetry.Exporter.net8.0.cs
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Expand Up @@ -15,6 +15,7 @@ public AzureMonitorExporterOptions(Azure.Monitor.OpenTelemetry.Exporter.AzureMon
public Azure.Core.TokenCredential Credential { get { throw null; } set { } }
public bool DisableOfflineStorage { get { throw null; } set { } }
public bool EnableLiveMetrics { get { throw null; } set { } }
public bool EnableTraceBasedLogsSampler { get { throw null; } set { } }
public float SamplingRatio { get { throw null; } set { } }
public string StorageDirectory { get { throw null; } set { } }
public double? TracesPerSecond { get { throw null; } set { } }
Expand Down
1 change: 1 addition & 0 deletions ...Monitor.OpenTelemetry.Exporter/api/Azure.Monitor.OpenTelemetry.Exporter.netstandard2.0.cs
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Expand Up @@ -15,6 +15,7 @@ public AzureMonitorExporterOptions(Azure.Monitor.OpenTelemetry.Exporter.AzureMon
public Azure.Core.TokenCredential Credential { get { throw null; } set { } }
public bool DisableOfflineStorage { get { throw null; } set { } }
public bool EnableLiveMetrics { get { throw null; } set { } }
public bool EnableTraceBasedLogsSampler { get { throw null; } set { } }
public float SamplingRatio { get { throw null; } set { } }
public string StorageDirectory { get { throw null; } set { } }
public double? TracesPerSecond { get { throw null; } set { } }
Expand Down
12 changes: 10 additions & 2 deletions sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/src/AzureMonitorExporterExtensions.cs
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Expand Up @@ -203,7 +203,12 @@ public static OpenTelemetryLoggerOptions AddAzureMonitorLogExporter(
options.Credential ??= credential;
}

return loggerOptions.AddProcessor(new BatchLogRecordExportProcessor(new AzureMonitorLogExporter(options)));
var exporter = new AzureMonitorLogExporter(options);
BaseProcessor<LogRecord> processor = options.EnableTraceBasedLogsSampler
? new LogFilteringProcessor(exporter)
: new BatchLogRecordExportProcessor(exporter);

return loggerOptions.AddProcessor(processor);
}

/// <summary>
Expand Down Expand Up @@ -271,7 +276,10 @@ public static LoggerProviderBuilder AddAzureMonitorLogExporter(
sp.EnsureNoUseAzureMonitorExporterRegistrations();

// TODO: Do we need provide an option to alter BatchExportLogRecordProcessorOptions?
return new BatchLogRecordExportProcessor(new AzureMonitorLogExporter(exporterOptions));
var exporter = new AzureMonitorLogExporter(exporterOptions);
return exporterOptions.EnableTraceBasedLogsSampler
? new LogFilteringProcessor(exporter)
: new BatchLogRecordExportProcessor(exporter);
});
}
}
Expand Down
10 changes: 10 additions & 0 deletions sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/src/AzureMonitorExporterOptions.cs
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Expand Up @@ -106,6 +106,16 @@ public enum ServiceVersion
/// </remarks>
public bool EnableLiveMetrics { get; set; } = true;

/// <summary>
/// Enables or disables filtering logs based on trace sampling decisions.
/// </summary>
/// <remarks>
/// When enabled, only logs associated with sampled traces are exported.
/// Logs without trace context are always exported.
/// This reduces log volume while maintaining trace-log correlation.
/// </remarks>
public bool EnableTraceBasedLogsSampler { get; set; } = true;

/// <summary>
/// Internal flag to control if Statsbeat is enabled.
/// </summary>
Expand Down
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