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Merged
martincostello merged 31 commits into from
Jun 5, 2026
Merged

[Exporter.Prometheus] Use snapshot tests for PrometheusSerializer #7354

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15ba450
[Exporter.Prometheus] Fix scope metadata
martincostello May 1, 2026
db4ca48
[Exporter.Prometheus] Update test cases
martincostello May 1, 2026
50942c7
[Exporter.Prometheus] Update CHANGELOGs
martincostello May 1, 2026
60a53b7
[Exporter.Prometheus] Address feedback
martincostello May 1, 2026
65db37d
Merge branch 'main' into fix-scope-metadata
martincostello May 1, 2026
a51c12a
[Exporter.Prometheus] Extend coverage
martincostello May 1, 2026
48c6919
Merge branch 'main' into fix-scope-metadata
martincostello May 4, 2026
9402121
Merge branch 'main' into fix-scope-metadata
martincostello May 5, 2026
ab0849c
Merge branch 'main' into fix-scope-metadata
martincostello May 5, 2026
926f714
[Exporter.Prometheus] Update CHANGELOGs
martincostello May 5, 2026
25e7374
Merge branch 'main' into fix-scope-metadata
martincostello May 13, 2026
00ab131
Merge branch 'main' into fix-scope-metadata
martincostello May 18, 2026
c5d2abb
Merge branch 'main' into fix-scope-metadata
martincostello May 19, 2026
9dfc038
[Exporter.Prometheus] Address feedback
martincostello May 19, 2026
a5a99b4
[Exporter.Prometheus] Fix CHANGELOGs
martincostello May 19, 2026
a9846cd
Merge branch 'main' into fix-scope-metadata
martincostello May 22, 2026
92924ae
Merge branch 'main' into fix-scope-metadata
martincostello May 30, 2026
691f9ce
[Exporter.Prometheus] Fix-up merge
martincostello May 30, 2026
36bbbe9
[Exporter.Prometheus] Address feedback
martincostello May 30, 2026
98141c1
Merge branch 'main' into fix-scope-metadata
martincostello Jun 1, 2026
44fa775
[Exporter.Prometheus] Fix SA1203
martincostello Jun 1, 2026
34ac7ea
[Exporter.Prometheus] Address feedback
martincostello Jun 1, 2026
0658b03
Merge branch 'main' into fix-scope-metadata
martincostello Jun 2, 2026
191f148
[Exporter.Prometheus] Address feedback
martincostello Jun 2, 2026
cb9605c
[Exporter.Prometheus] Snapshot tests
martincostello Jun 2, 2026
a8f4d61
[Exporter.Prometheus] Add more snapshots
martincostello Jun 2, 2026
cc8c90a
[Exporter.Prometheus] Fix snapshots
martincostello Jun 3, 2026
2842649
Merge branch 'main' into prometheus-verify-tests
martincostello Jun 3, 2026
bd2f85b
Merge branch 'main' into prometheus-verify-tests
martincostello Jun 3, 2026
aba3121
[Exporter.Prometheus] Fix build
martincostello Jun 3, 2026
e5e871c
[Exporter.Prometheus] Address feedback
martincostello Jun 3, 2026
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5 changes: 5 additions & 0 deletions ...ter.Prometheus.AspNetCore.Tests/OpenTelemetry.Exporter.Prometheus.AspNetCore.Tests.csproj
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@
<PackageReference Include="Microsoft.AspNetCore.TestHost" />
<PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" />
<PackageReference Include="Testcontainers" />
<PackageReference Include="Verify.Xunit" />
</ItemGroup>

<ItemGroup>
Expand Down Expand Up @@ -57,4 +58,8 @@
<EmbeddedResource Include="$(RepoRoot)\test\OpenTelemetry.Exporter.Prometheus.HttpListener.Tests\prometheus.Dockerfile" LogicalName="prometheus.Dockerfile" />
</ItemGroup>

<ItemGroup>
<AssemblyMetadata Include="PrometheusSerializerTestsSnapshotsPath" Value="$(RepoRoot)\test\OpenTelemetry.Exporter.Prometheus.HttpListener.Tests\snapshots" />
</ItemGroup>
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martincostello marked this conversation as resolved.

</Project>
5 changes: 5 additions & 0 deletions ...Prometheus.HttpListener.Tests/OpenTelemetry.Exporter.Prometheus.HttpListener.Tests.csproj
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@

<ItemGroup>
<PackageReference Include="Testcontainers" />
<PackageReference Include="Verify.Xunit" />
</ItemGroup>

<ItemGroup>
Expand All @@ -51,4 +52,8 @@
<EmbeddedResource Include="*.Dockerfile" LogicalName="%(FileName)%(Extension)" />
</ItemGroup>

<ItemGroup>
<AssemblyMetadata Include="PrometheusSerializerTestsSnapshotsPath" Value="$([System.IO.Path]::GetFullPath('$(MSBuildThisFileDirectory)/snapshots'))" />
</ItemGroup>

</Project>
123 changes: 32 additions & 91 deletions .../OpenTelemetry.Exporter.Prometheus.HttpListener.Tests/PrometheusCollectionManagerTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,10 +2,13 @@
// SPDX-License-Identifier: Apache-2.0

using System.Diagnostics.Metrics;
using System.Runtime.CompilerServices;
using System.Text;
using System.Text.RegularExpressions;
using OpenTelemetry.Metrics;
using OpenTelemetry.Resources;
#if PROMETHEUS_HTTP_LISTENER
using OpenTelemetry.Tests;
#endif

namespace OpenTelemetry.Exporter.Prometheus.Tests;

Expand All @@ -22,7 +25,7 @@ public async Task EnterExitCollectTest(int scrapeResponseCacheDurationMillisecon
using var cts = new CancellationTokenSource(testTimeout);

var cacheEnabled = scrapeResponseCacheDurationMilliseconds != 0;
using var meter = new Meter(Utils.GetCurrentMethodName());
using var meter = CreateMeter();

using var provider = Sdk.CreateMeterProviderBuilder()
.AddMeter(meter.Name)
Expand Down Expand Up @@ -203,7 +206,7 @@ async Task<Task<Response>[]> CollectInParallelAsync(bool advanceClock)
[Fact]
public async Task EnterCollectWaitsForActiveReadersToExit()
{
using var meter = new Meter(Utils.GetCurrentMethodName());
using var meter = CreateMeter();
#if PROMETHEUS_HTTP_LISTENER
using var provider = CreateMeterProviderWithRandomPort(meter);
#elif PROMETHEUS_ASPNETCORE
Expand Down Expand Up @@ -298,6 +301,7 @@ public async Task OpenMetricsDoesNotEmitScopeInfoMetricFamily()
using var meter = new Meter("test_meter", "1.0.0", [new("library.mascot", "dotnetbot")], scope: null);

using var provider = Sdk.CreateMeterProviderBuilder()
.ConfigureResource((p) => p.AddAttributes([new("service.name", "prometheus")]))
.AddMeter(meter.Name)
#if PROMETHEUS_HTTP_LISTENER
.AddPrometheusHttpListener()
Expand All @@ -320,10 +324,7 @@ public async Task OpenMetricsDoesNotEmitScopeInfoMetricFamily()
response.OpenMetricsView.Offset,
response.OpenMetricsView.Count);

Assert.DoesNotContain("# TYPE otel_scope info", output, StringComparison.Ordinal);
Assert.DoesNotContain("# HELP otel_scope Scope metadata", output, StringComparison.Ordinal);
Assert.DoesNotContain("otel_scope_info{", output, StringComparison.Ordinal);
Assert.Contains("counter_1_total{otel_scope_name=\"test_meter\",otel_scope_version=\"1.0.0\",otel_scope_library_mascot=\"dotnetbot\"} 1", output, StringComparison.Ordinal);
await Verify(output, "txt", PrometheusSerializerTests.VerifySettings);
}
finally
{
Expand All @@ -337,6 +338,7 @@ public async Task OpenMetricsDoesNotReserveOtelScopeMetricFamilyNames()
using var meter = new Meter("test_meter", "1.0.0");

using var provider = Sdk.CreateMeterProviderBuilder()
.ConfigureResource((p) => p.AddAttributes([new("service.name", "prometheus")]))
.AddMeter(meter.Name)
#if PROMETHEUS_HTTP_LISTENER
.AddPrometheusHttpListener()
Expand All @@ -360,10 +362,7 @@ public async Task OpenMetricsDoesNotReserveOtelScopeMetricFamilyNames()
response.OpenMetricsView.Offset,
response.OpenMetricsView.Count);

Assert.Contains("# TYPE otel_scope gauge", output, StringComparison.Ordinal);
Assert.Contains("otel_scope{otel_scope_name=\"test_meter\",otel_scope_version=\"1.0.0\"} 1", output, StringComparison.Ordinal);
Assert.Contains("# TYPE otel_scope_info gauge", output, StringComparison.Ordinal);
Assert.Contains("otel_scope_info{otel_scope_name=\"test_meter\",otel_scope_version=\"1.0.0\"} 2", output, StringComparison.Ordinal);
await Verify(output, "txt", PrometheusSerializerTests.VerifySettings);
}
finally
{
Expand All @@ -374,9 +373,10 @@ public async Task OpenMetricsDoesNotReserveOtelScopeMetricFamilyNames()
[Fact]
public async Task DuplicateMetricMetadataIsWrittenOncePerScrape()
{
using var meter = new Meter(Utils.GetCurrentMethodName());
using var meter = CreateMeter();

using var provider = Sdk.CreateMeterProviderBuilder()
.ConfigureResource((p) => p.AddAttributes([new("service.name", "prometheus")]))
.AddMeter(meter.Name)
#if PROMETHEUS_HTTP_LISTENER
.AddPrometheusHttpListener()
Expand All @@ -401,13 +401,7 @@ public async Task DuplicateMetricMetadataIsWrittenOncePerScrape()
var view = response.PlainTextView;
var output = Encoding.UTF8.GetString(view.Array!, view.Offset, view.Count);

#pragma warning disable SYSLIB1045 // Convert to 'GeneratedRegexAttribute'.
Assert.Single(Regex.Matches(output, "^# TYPE test_metric_bytes_total counter$", RegexOptions.Multiline).Cast<Match>());
Assert.Single(Regex.Matches(output, "^# UNIT test_metric_bytes_total bytes$", RegexOptions.Multiline).Cast<Match>());
Assert.Single(Regex.Matches(output, "^# HELP test_metric_bytes_total Test help$", RegexOptions.Multiline).Cast<Match>());
#pragma warning restore SYSLIB1045 // Convert to 'GeneratedRegexAttribute'.
Assert.Contains("test_metric_bytes_total{otel_scope_name=\"" + meter.Name + "\",source=\"a\"} 1", output, StringComparison.Ordinal);
Assert.Contains("test_metric_bytes_total{otel_scope_name=\"" + meter.Name + "\",source=\"b\"} 2", output, StringComparison.Ordinal);
await Verify(output, "txt", PrometheusSerializerTests.VerifySettings);
}
finally
{
Expand All @@ -418,9 +412,10 @@ public async Task DuplicateMetricMetadataIsWrittenOncePerScrape()
[Fact]
public async Task MetricMetadataDiscoveredLaterIsWrittenBeforeSamples()
{
using var meter = new Meter(Utils.GetCurrentMethodName());
using var meter = CreateMeter();

using var provider = Sdk.CreateMeterProviderBuilder()
.ConfigureResource((p) => p.AddAttributes([new("service.name", "prometheus")]))
.AddMeter(meter.Name)
#if PROMETHEUS_HTTP_LISTENER
.AddPrometheusHttpListener()
Expand All @@ -445,19 +440,7 @@ public async Task MetricMetadataDiscoveredLaterIsWrittenBeforeSamples()
var view = response.PlainTextView;
var output = Encoding.UTF8.GetString(view.Array!, view.Offset, view.Count);

var typeIndex = output.IndexOf("# TYPE test_metric_total counter", StringComparison.Ordinal);
var helpIndex = output.IndexOf("# HELP test_metric_total Test help", StringComparison.Ordinal);
var sampleAIndex = output.IndexOf("test_metric_total{otel_scope_name=\"" + meter.Name + "\",source=\"a\"} 1", StringComparison.Ordinal);
var sampleBIndex = output.IndexOf("test_metric_total{otel_scope_name=\"" + meter.Name + "\",source=\"b\"} 2", StringComparison.Ordinal);

Assert.True(typeIndex >= 0, "No TYPE found.");
Assert.True(helpIndex >= 0, "No HELP found.");
Assert.True(sampleAIndex >= 0, "No sample A found.");
Assert.True(sampleBIndex >= 0, "No sample B found.");
Assert.True(typeIndex < sampleAIndex, "TYPE appears after sample A.");
Assert.True(typeIndex < sampleBIndex, "TYPE appears after sample B.");
Assert.True(helpIndex < sampleAIndex, "HELP appears after sample A.");
Assert.True(helpIndex < sampleBIndex, "HELP appears after sample B.");
await Verify(output, "txt", PrometheusSerializerTests.VerifySettings);
}
finally
{
Expand All @@ -468,9 +451,10 @@ public async Task MetricMetadataDiscoveredLaterIsWrittenBeforeSamples()
[Fact]
public async Task MetricUnitDiscoveredLaterIsWrittenBeforeSamples()
{
using var meter = new Meter(Utils.GetCurrentMethodName());
using var meter = CreateMeter();

using var provider = Sdk.CreateMeterProviderBuilder()
.ConfigureResource((p) => p.AddAttributes([new("service.name", "prometheus")]))
.AddMeter(meter.Name)
#if PROMETHEUS_HTTP_LISTENER
.AddPrometheusHttpListener()
Expand All @@ -495,19 +479,7 @@ public async Task MetricUnitDiscoveredLaterIsWrittenBeforeSamples()
var view = response.PlainTextView;
var output = Encoding.UTF8.GetString(view.Array!, view.Offset, view.Count);

var typeIndex = output.IndexOf("# TYPE test_metric_bytes_total counter", StringComparison.Ordinal);
var unitIndex = output.IndexOf("# UNIT test_metric_bytes_total bytes", StringComparison.Ordinal);
var sampleAIndex = output.IndexOf("test_metric_bytes_total{otel_scope_name=\"" + meter.Name + "\",source=\"a\"} 1", StringComparison.Ordinal);
var sampleBIndex = output.IndexOf("test_metric_bytes_total{otel_scope_name=\"" + meter.Name + "\",source=\"b\"} 2", StringComparison.Ordinal);

Assert.True(typeIndex >= 0, "No TYPE found.");
Assert.True(unitIndex >= 0, "No UNIT found.");
Assert.True(sampleAIndex >= 0, "No sample A found.");
Assert.True(sampleBIndex >= 0, "No sample B found.");
Assert.True(typeIndex < sampleAIndex, "TYPE appears after sample A.");
Assert.True(typeIndex < sampleBIndex, "TYPE appears after sample B.");
Assert.True(unitIndex < sampleAIndex, "UNIT appears after sample A.");
Assert.True(unitIndex < sampleBIndex, "UNIT appears after sample B.");
await Verify(output, "txt", PrometheusSerializerTests.VerifySettings);
}
finally
{
Expand All @@ -518,9 +490,10 @@ public async Task MetricUnitDiscoveredLaterIsWrittenBeforeSamples()
[Fact]
public async Task MetricHelpAndUnitDiscoveredTogetherLaterAreBothWrittenBeforeSamples()
{
using var meter = new Meter(Utils.GetCurrentMethodName());
using var meter = CreateMeter();

using var provider = Sdk.CreateMeterProviderBuilder()
.ConfigureResource((p) => p.AddAttributes([new("service.name", "prometheus")]))
.AddMeter(meter.Name)
#if PROMETHEUS_HTTP_LISTENER
.AddPrometheusHttpListener()
Expand All @@ -545,23 +518,7 @@ public async Task MetricHelpAndUnitDiscoveredTogetherLaterAreBothWrittenBeforeSa
var view = response.PlainTextView;
var output = Encoding.UTF8.GetString(view.Array!, view.Offset, view.Count);

var typeIndex = output.IndexOf("# TYPE test_metric_bytes_total counter", StringComparison.Ordinal);
var unitIndex = output.IndexOf("# UNIT test_metric_bytes_total bytes", StringComparison.Ordinal);
var helpIndex = output.IndexOf("# HELP test_metric_bytes_total Test help", StringComparison.Ordinal);
var sampleAIndex = output.IndexOf("test_metric_bytes_total{otel_scope_name=\"" + meter.Name + "\",source=\"a\"} 1", StringComparison.Ordinal);
var sampleBIndex = output.IndexOf("test_metric_bytes_total{otel_scope_name=\"" + meter.Name + "\",source=\"b\"} 2", StringComparison.Ordinal);

Assert.True(typeIndex >= 0, "No TYPE found.");
Assert.True(unitIndex >= 0, "No UNIT found.");
Assert.True(helpIndex >= 0, "No HELP found.");
Assert.True(sampleAIndex >= 0, "No sample A found.");
Assert.True(sampleBIndex >= 0, "No sample B found.");
Assert.True(typeIndex < sampleAIndex, "TYPE appears after sample A.");
Assert.True(typeIndex < sampleBIndex, "TYPE appears after sample B.");
Assert.True(unitIndex < sampleAIndex, "UNIT appears after sample A.");
Assert.True(unitIndex < sampleBIndex, "UNIT appears after sample B.");
Assert.True(helpIndex < sampleAIndex, "HELP appears after sample A.");
Assert.True(helpIndex < sampleBIndex, "HELP appears after sample B.");
await Verify(output, "txt", PrometheusSerializerTests.VerifySettings);
}
finally
{
Expand All @@ -572,9 +529,10 @@ public async Task MetricHelpAndUnitDiscoveredTogetherLaterAreBothWrittenBeforeSa
[Fact]
public async Task ConflictingMetricTypesAreDroppedFromAScrape()
{
using var meter = new Meter(Utils.GetCurrentMethodName());
using var meter = CreateMeter();

using var provider = Sdk.CreateMeterProviderBuilder()
.ConfigureResource((p) => p.AddAttributes([new("service.name", "prometheus")]))
.AddMeter(meter.Name)
#if PROMETHEUS_HTTP_LISTENER
.AddPrometheusHttpListener()
Expand All @@ -597,9 +555,7 @@ public async Task ConflictingMetricTypesAreDroppedFromAScrape()
var view = response.OpenMetricsView;
var output = Encoding.UTF8.GetString(view.Array!, view.Offset, view.Count);

Assert.DoesNotContain("# TYPE test_metric", output, StringComparison.Ordinal);
Assert.DoesNotContain("test_metric_total", output, StringComparison.Ordinal);
Assert.Contains("# EOF", output, StringComparison.Ordinal);
await Verify(output, "txt", PrometheusSerializerTests.VerifySettings);
}
finally
{
Expand All @@ -610,10 +566,12 @@ public async Task ConflictingMetricTypesAreDroppedFromAScrape()
[Fact]
public async Task OpenMetricsWritesMetricFamiliesContiguously()
{
using var meter1 = new Meter($"{Utils.GetCurrentMethodName()}.one");
using var meter2 = new Meter($"{Utils.GetCurrentMethodName()}.two");
var prefix = nameof(this.OpenMetricsWritesMetricFamiliesContiguously);
using var meter1 = new Meter($"{prefix}.one");
using var meter2 = new Meter($"{prefix}.two");

using var provider = Sdk.CreateMeterProviderBuilder()
.ConfigureResource((p) => p.AddAttributes([new("service.name", "prometheus")]))
.AddMeter(meter1.Name)
.AddMeter(meter2.Name)
#if PROMETHEUS_HTTP_LISTENER
Expand All @@ -637,33 +595,16 @@ public async Task OpenMetricsWritesMetricFamiliesContiguously()
var view = response.OpenMetricsView;
var output = Encoding.UTF8.GetString(view.Array!, view.Offset, view.Count);

var testMetricTypeIndex = output.IndexOf("# TYPE test_metric gauge", StringComparison.Ordinal);

Assert.DoesNotContain("# TYPE otel_scope info", output, StringComparison.Ordinal);
Assert.DoesNotContain("# HELP otel_scope Scope metadata", output, StringComparison.Ordinal);
Assert.DoesNotContain("otel_scope_info{", output, StringComparison.Ordinal);
Assert.True(testMetricTypeIndex >= 0, "No TYPE found for test_metric.");

var nextTypeIndex = output.IndexOf("\n# TYPE ", testMetricTypeIndex + 1, StringComparison.Ordinal);
if (nextTypeIndex < 0)
{
nextTypeIndex = output.IndexOf("\n# EOF", testMetricTypeIndex + 1, StringComparison.Ordinal);
}

Assert.True(nextTypeIndex > testMetricTypeIndex, "No subsequent metric family found after test_metric.");

var testMetricBlock = output.Substring(testMetricTypeIndex, nextTypeIndex - testMetricTypeIndex);
Assert.Contains("# HELP test_metric Test help", testMetricBlock, StringComparison.Ordinal);
Assert.Contains($"test_metric{{otel_scope_name=\"{meter1.Name}\"}} 1", testMetricBlock, StringComparison.Ordinal);
Assert.Contains($"test_metric{{otel_scope_name=\"{meter2.Name}\"}} 2", testMetricBlock, StringComparison.Ordinal);
Assert.DoesNotContain("other_metric{", testMetricBlock, StringComparison.Ordinal);
await Verify(output, "txt", PrometheusSerializerTests.VerifySettings);
}
finally
{
exporter.CollectionManager.ExitCollect();
}
}

private static Meter CreateMeter([CallerMemberName] string name = "") => new(name);

#if PROMETHEUS_HTTP_LISTENER
private static MeterProvider CreateMeterProviderWithRandomPort(Meter meter)
{
Expand Down
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