feat(tracing): part 10 da retriever tracing

[chatton]

Overview

ref #2956

Adding tracing for da retrieval, needed to bump sonic dep after go version bump.

[github-actions]

The latest Buf updates on your PR. Results from workflow CI / buf-check (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	⏩ skipped	✅ passed	✅ passed	Jan 19, 2026, 11:18 AM

[gemini-code-assist]

Summary of Changes

Hello @chatton, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the system's observability by integrating OpenTelemetry tracing into the Data Availability (DA) retriever. It introduces a tracing decorator that wraps the existing DARetriever to automatically instrument its RetrieveFromDA method. This allows for the collection of detailed telemetry data, including operational attributes and error information, which is crucial for monitoring performance and diagnosing issues within the DA retrieval process. The tracing is conditionally applied based on the system's instrumentation configuration, ensuring that this feature can be enabled or disabled as needed without altering core logic.

Highlights

• OpenTelemetry Tracing for DARetriever: Introduced OpenTelemetry tracing for the DARetriever interface by adding a tracedDARetriever decorator. This decorator instruments the RetrieveFromDA method to capture execution details.
• Detailed Span Attributes: The tracing implementation records relevant attributes such as da.height, event.count, and block.heights within the span, providing granular context for each DA retrieval operation.
• Error Handling in Tracing: Errors encountered during DA retrieval are now recorded in the span, and the span's status is set to Error, facilitating easier identification and debugging of failures.
• Conditional Tracing Integration: The Syncer component has been updated to conditionally apply the WithTracingDARetriever decorator, ensuring that tracing is only enabled when instrumentation is configured to do so.
• Comprehensive Unit Tests: New unit tests have been added for the tracedDARetriever to verify its behavior across various scenarios, including successful retrievals, cases with no events, and error conditions.

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[claude]

Claude finished @chatton's task in 1m 41s —— View job

---

Code Review Complete ✓

I've completed a comprehensive review of this PR which adds OpenTelemetry tracing for the DA retriever. Overall, this is a well-implemented and valuable addition to the observability infrastructure. The code follows established patterns and includes solid test coverage.

---

Summary

What's Good:

• Clean decorator pattern implementation following existing tracing conventions
• Comprehensive test coverage with multiple scenarios
• Proper error handling and span status management
• Meaningful trace attributes for observability
• Conditional tracing application based on instrumentation config

Areas for Improvement:

• Test coverage gap for block.heights attribute verification
• Minor code organization opportunity in syncer.go

---

Detailed Findings

1. Code Quality & Architecture ✓

Strengths:

• The decorator pattern is correctly applied, consistent with tracedClient in block/internal/da/tracing.go
• Interface compliance is verified with compile-time check (var _ DARetriever = (*tracedDARetriever)(nil))
• Tracer naming follows convention: "ev-node/da-retriever"
• Integration in syncer.go:204-206 is clean and conditionally applied

Observations:
The implementation correctly wraps the RetrieveFromDA method and propagates the traced context to the inner retriever, enabling distributed tracing.

2. Error Handling & Resilience ✓

Strengths:

• Errors are properly recorded with span.RecordError(err) (line 40)
• Span status correctly set to codes.Error with error message (line 41)
• Error is returned unchanged, preserving error chain (line 42)
• Context propagation is correct, allowing for cancellation/timeout handling

Good Practice:
The implementation follows OpenTelemetry best practices by recording both the error event and setting the span status, which is crucial for error tracking in observability platforms.

3. Security ✓

No Issues Found:

• No sensitive data exposed in trace attributes
• DA height and event counts are safe to trace
• Block heights are metadata, not sensitive information
• No credential or PII leakage risks

4. Performance & Resource Efficiency ✓

Strengths:

• Minimal overhead: only creates span when tracing is enabled
• Efficient attribute setting after successful retrieval
• Block heights slice allocation is reasonable (line 49-52)
• Deferred span.End() ensures proper cleanup (line 36)

Minor Observation:
The heights slice allocation could be optimized with pre-sizing, but given typical event counts, this is negligible.

5. Testing & Reliability ⚠️

Strengths:

• Three test scenarios cover success, no events, and error cases
• Test helper setupDARetrieverTrace provides clean test setup
• Mock implementation is straightforward and reusable
• Span recording verification is thorough

Issue - Missing Test Coverage:
The block.heights attribute (set on line 53 of da_retriever_tracing.go) is not verified in tests. This was also noted by Gemini Code Assist's review.

Recommendation:
Add verification for the block.heights attribute in TestTracedDARetriever_RetrieveFromDA_Success. Here's the suggested test enhancement:

// In da_retriever_tracing_test.go:79, after line 79:
testutil.RequireAttribute(t, attrs, "event.count", 2)

// Add verification for block.heights
var heightsFound bool
for _, attr := range attrs {
    if attr.Key == "block.heights" {
        heightsFound = true
        require.Equal(t, attribute.INT64SLICE, attr.Value.Type())
        require.Equal(t, []int64{100, 101}, attr.Value.AsInt64Slice())
        break
    }
}
require.True(t, heightsFound, "block.heights attribute not found")

Coverage Report Analysis:
Codecov shows 92% patch coverage with 2 lines missing in syncer.go:204-205. These lines are the conditional tracing wrapper - they may not be covered if integration tests don't enable instrumentation. This is acceptable for initialization code, but consider adding a test that verifies the tracing wrapper is applied when Instrumentation.IsTracingEnabled() returns true.

6. Documentation & Developer Experience ✓

Strengths:

• Clear function and type comments
• Tracer name is descriptive and follows naming conventions
• Integration point is well-documented in syncer.go
• PR description explains the purpose and dependency bump

Minor Enhancement:
Consider adding a package-level comment in da_retriever_tracing.go explaining the tracing decorator pattern for developers unfamiliar with this approach.

---

Dependency Update

The sonic version bump (v1.14.2 in test/docker-e2e/go.mod:20) is noted as necessary for Go 1.25 compatibility. This is a transitive dependency update and appears safe.

---

Recommendations

High Priority

1. Add test verification for block.heights attribute (see recommendation in Testing section above)
   • File: block/internal/syncing/da_retriever_tracing_test.go:79
   • This ensures the implementation matches the observed behavior

Low Priority

2. Consider adding integration test that verifies tracing decorator is applied when instrumentation is enabled

   • This would improve coverage of lines 204-205 in syncer.go
   • Not critical as the logic is straightforward

3. Package-level documentation - Add comment explaining the decorator pattern

   • Helps onboard new developers to the tracing infrastructure

---

Conclusion

This PR represents solid engineering work that follows project conventions and adds valuable observability. The tracing implementation is correct, efficient, and follows OpenTelemetry best practices. The test gap for block.heights is minor but should be addressed for completeness.

Recommendation: Approve with minor test enhancement

The code is production-ready, but adding the block.heights attribute verification would ensure complete test coverage of the tracing behavior. Once CI passes and the optional test enhancement is added, this is ready to merge.

---

[gemini-code-assist]

Code Review

This pull request introduces OpenTelemetry tracing for the DARetriever, which is a great addition for observability. The implementation of the tracedDARetriever decorator is clean and follows best practices for tracing in Go. The new code is well-structured and includes corresponding unit tests.

My main feedback is a suggestion to enhance the tests to ensure all new tracing attributes are verified. Overall, this is a solid contribution.

[gemini-code-assist]

This test is great for verifying the success case. To make it more comprehensive, it would be beneficial to also assert that the block.heights attribute is correctly set on the span when events are returned.

The testutil.RequireAttribute helper doesn't seem to support slice attributes, so you might need to perform this check manually. Here's a suggestion to add this verification:

Suggested change

	testutil.RequireAttribute(t, attrs, "event.count", 2)
	testutil.RequireAttribute(t, attrs, "event.count", 2)
	// Check for block.heights attribute
	var heightsValue attribute.Value
	for _, attr := range attrs {
	if attr.Key == "block.heights" {
	heightsValue = attr.Value
	break
	}
	}
	require.NotNil(t, heightsValue, "attribute 'block.heights' not found")
	require.Equal(t, attribute.INT64SLICE, heightsValue.Type())
	require.Equal(t, []int64{100, 101}, heightsValue.AsInt64Slice())

[codecov]

Codecov Report

❌ Patch coverage is 92.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.25%. Comparing base (50b35a9) to head (65fda65).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
block/internal/syncing/syncer.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2991      +/-   ##
==========================================
+ Coverage   59.17%   59.25%   +0.08%     
==========================================
  Files         105      106       +1     
  Lines        9998    10023      +25     
==========================================
+ Hits         5916     5939      +23     
- Misses       3454     3456       +2     
  Partials      628      628              

Flag	Coverage Δ
combined	59.25% <92.00%> (+0.08%)	⬆️

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