feat(otel): export OTLP traces

[yordis]

• EventStore needs all OpenTelemetry signals to leave the node through the same OTLP configuration surface.
• Operators should not need a separate tracing setup model when logs and metrics already support shared and signal-specific OTLP destinations.
• Baseline request tracing makes the observability path complete enough for collector-backed deployments to validate logs, metrics, and traces together.

[cursor]

PR Summary

Medium Risk
Adds new OpenTelemetry tracing export and ASP.NET Core request instrumentation, which can affect runtime performance and telemetry routing if misconfigured.

Overview
Adds OTLP trace export alongside existing logs/metrics export, using the same shared + per-signal EventStore:OpenTelemetry:* configuration model.

Wires tracing into node startup via OpenTelemetry WithTracing, enabling ASP.NET Core request instrumentation and an OTLP exporter when Traces:Enabled (or Traces:Otlp settings) are present; includes new config helpers/tests and updates docs plus build/license metadata for the new OpenTelemetry.Instrumentation.AspNetCore dependency.

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[coderabbitai]

Walkthrough

This pull request adds OpenTelemetry traces support to EventStore's OTLP export infrastructure. Changes include: new trace configuration prefixes and enablement check; tracing setup in ClusterVNodeStartup with ASP.NET Core instrumentation; the OpenTelemetry.Instrumentation.AspNetCore NuGet dependency; comprehensive test coverage of OTLP traces configuration behavior; and updated documentation reflecting traces alongside existing metrics and logs exports.

Changes

OpenTelemetry Traces Support

Layer / File(s)	Summary
Configuration Data Shape src/EventStore.Core/Configuration/OpenTelemetryConfiguration.cs	Introduces OtlpTracesPrefix and OtlpTracesOtlpPrefix constants, and adds OtlpTracesEnabled() extension method to detect whether traces are enabled via configuration or per-signal OTLP section.
Dependency Declarations src/Directory.Packages.props, src/EventStore.Core/EventStore.Core.csproj	Adds centrally managed NuGet package version for OpenTelemetry.Instrumentation.AspNetCore (1.15.2) and declares the package reference in the core project.
Core Tracing Setup src/EventStore.Core/ClusterVNodeStartup.cs	Introduces ConfigureTracing helper method that configures the tracer provider with eventstore service resource, adds ASP.NET Core instrumentation, and conditionally binds OTLP exporter when traces are enabled.
License Configuration qodana.yaml, src/qodana.yaml	Registers OpenTelemetry.Instrumentation.AspNetCore v1.15.2 with Apache-2.0 license in Qodana dependency overrides.
Tests & Documentation src/EventStore.Core.XUnit.Tests/OpenTelemetry/OtlpTracingConfigurationTests.cs, docs/diagnostics/integrations.md	Adds five configuration tests covering disabled-by-default behavior, enablement via runtime switch, per-signal section override behavior, and endpoint/header/protocol parsing. Documentation updated to describe traces in OpenTelemetry exports, sample config, environment variables, and troubleshooting guidance.

Sequence Diagram

sequenceDiagram
    participant App as Application<br/>Startup
    participant Config as Configuration<br/>System
    participant OTLP as OpenTelemetry<br/>Builder
    participant Tracer as Tracer<br/>Provider
    participant Instr as ASP.NET Core<br/>Instrumentation
    participant Exporter as OTLP<br/>Exporter

    App->>Config: Read EventStore:OpenTelemetry:Traces config
    Config-->>App: Traces enabled + OTLP endpoint
    App->>OTLP: ConfigureTracing(builder, config)
    OTLP->>Tracer: Set service resource name = "eventstore"
    OTLP->>Instr: Add AspNetCore instrumentation
    OTLP->>Exporter: Configure OTLP exporter with endpoint
    Exporter-->>OTLP: Exporter ready
    Note over App,Exporter: At request time
    App->>Instr: HTTP request arrives
    Instr->>Tracer: Record span
    Tracer->>Exporter: Export spans
    Exporter-->>Exporter: Send to OTLP collector

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• feat(otel): support signal-specific OTLP export #148: Extends the signal-specific OTLP export changes from PR #148 by adding traces support (config prefixes, builder setup, tests, docs) to the existing per-signal OpenTelemetry export subsystem.

Poem

🐰 Hops with glee through telemetry trails,
Traces now dance where the story tells tales,
Config, instrumentation, OTLP takes flight,
AspNetCore whispers each span in the night—
Signals aligned! Metrics, logs, traces in sight!

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'feat(otel): export OTLP traces' accurately and clearly summarizes the main change - adding OTLP trace export functionality to the EventStore.
Description check	✅ Passed	The description explains the motivation and goals for adding OTLP trace export, relating directly to the changeset which implements tracing support alongside existing metrics and logs.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

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• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch yordis/feat-otlp-tracing

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[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[coderabbitai]

🧹 Nitpick comments (1)

src/EventStore.Core/ClusterVNodeStartup.cs (1)

265-265: ⚡ Quick win

Extract the "eventstore" service-name literal into a shared constant.

The service name "eventstore" is used identically in both ConfigureMetrics (line 265) and ConfigureTracing (line 347). Extracting it prevents a future rename from silently diverging the two signal pipelines.

♻️ Proposed refactor

+   private const string ServiceName = "eventstore";

    private static void ConfigureMetrics(...)
    {
        meterOptions
-           .SetResourceBuilder(ResourceBuilder.CreateDefault().AddService("eventstore"))
+           .SetResourceBuilder(ResourceBuilder.CreateDefault().AddService(ServiceName))
            ...
    }

    private static void ConfigureTracing(...)
    {
-       tracerOptions.SetResourceBuilder(ResourceBuilder.CreateDefault().AddService("eventstore"));
+       tracerOptions.SetResourceBuilder(ResourceBuilder.CreateDefault().AddService(ServiceName));
        ...
    }

Also applies to: 347-347

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@src/EventStore.Core/ClusterVNodeStartup.cs` at line 265, Extract the literal
"eventstore" into a shared constant and use that constant in both metrics and
tracing setup to avoid divergence: define a const string (e.g., ServiceName or
EventStoreServiceName) and replace occurrences of
ResourceBuilder.CreateDefault().AddService("eventstore") and the matching call
in ConfigureTracing with ResourceBuilder.CreateDefault().AddService(ServiceName)
(or the chosen constant) so both ConfigureMetrics and ConfigureTracing reference
the same identifier.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@src/EventStore.Core/ClusterVNodeStartup.cs`:
- Line 265: Extract the literal "eventstore" into a shared constant and use that
constant in both metrics and tracing setup to avoid divergence: define a const
string (e.g., ServiceName or EventStoreServiceName) and replace occurrences of
ResourceBuilder.CreateDefault().AddService("eventstore") and the matching call
in ConfigureTracing with ResourceBuilder.CreateDefault().AddService(ServiceName)
(or the chosen constant) so both ConfigureMetrics and ConfigureTracing reference
the same identifier.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: c961157c-126a-4a3d-a794-bccb94fc7f29

📥 Commits

Reviewing files that changed from the base of the PR and between 21a0e0c and 401fc38.

📒 Files selected for processing (8)

• docs/diagnostics/integrations.md
• qodana.yaml
• src/Directory.Packages.props
• src/EventStore.Core.XUnit.Tests/OpenTelemetry/OtlpTracingConfigurationTests.cs
• src/EventStore.Core/ClusterVNodeStartup.cs
• src/EventStore.Core/Configuration/OpenTelemetryConfiguration.cs
• src/EventStore.Core/EventStore.Core.csproj
• src/qodana.yaml