fix: correctly disable the sdk sampling when no endpoint is defined

[shrugs]

• disables the allocation of otel spans when the OTEL_EXPORTER_OTLP_ENDPOINT doesn't exist

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3 Skipped Deployments

Project	Deployment	Actions	Updated (UTC)
admin.ensnode.io	Skipped		Apr 2, 2026 6:01pm
ensnode.io	Skipped		Apr 2, 2026 6:01pm
ensrainbow.io	Skipped		Apr 2, 2026 6:01pm

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: 2e56cf39-4d3f-4003-a8c5-a5e675fbe892

📥 Commits

Reviewing files that changed from the base of the PR and between 6e2c1c0 and 554da73.

📒 Files selected for processing (1)

• apps/ensapi/src/lib/instrumentation/index.ts

📝 Walkthrough

Walkthrough

OpenTelemetry instrumentation configuration was refactored to replace conditional span processor assembly with fixed BatchSpanProcessor configuration, introduce sampling control via AlwaysOnSampler/AlwaysOffSampler based on environment variables, and simplify debug logging gating. Server startup warm-up comments were clarified without functional changes.

Changes

Cohort / File(s)	Summary
Server Startup Documentation apps/ensapi/src/index.ts	Simplified warm-up behavior comments; removed detailed SWR cache proxy initialization explanation while retaining explicit indexingStatusCache.read() call.
OpenTelemetry Instrumentation apps/ensapi/src/lib/instrumentation/index.ts	Replaced conditional span processor array logic with fixed BatchSpanProcessor(OTLPTraceExporter) configuration; introduced sampling control via AlwaysOnSampler (when endpoint exists) or AlwaysOffSampler (fallback); refactored debug logging gating to use OTEL_DEBUG environment variable via boolean variable instead of direct conditional check.

Possibly related PRs

• feat(ensapi): add tracing support with Pothos plugins and enhance GraphQL execution tracing #1855: Directly related OpenTelemetry tracing support additions; these instrumentation configuration changes build upon and refine the tracing infrastructure.

Poem

🐰 A trace through the code, now cleaner and bright,
With samplers deciding what's on and what's off,
The warm-up still hops, processors stand tight,
Our burrow of telemetry's ready to scoff! ✨

---

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The PR description is significantly incomplete. It contains only a single bullet point when the template requires multiple sections including Summary, Why, Testing, Notes for Reviewer, and a Pre-Review Checklist.	Expand the description to include all required template sections: Summary (1-3 bullets), Why (with GitHub issue links if relevant), Testing (how it was tested), Notes for Reviewer (optional but recommended), and the Pre-Review Checklist with blocking items.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: disabling SDK sampling when no endpoint is defined, which aligns with the core objective of the PR.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/noop-spans

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[greptile-apps]

Greptile Summary

This PR fixes telemetry overhead when no OTLP endpoint is configured by switching from a conditionally-added BatchSpanProcessor to a constant AlwaysOffSampler/AlwaysOnSampler pair that gates span recording at the sampler level.

Key changes:

• Introduces enabled (driven by OTEL_EXPORTER_OTLP_ENDPOINT) and debug (driven by OTEL_DEBUG) boolean flags for clarity.
• When enabled is false, AlwaysOffSampler is used so no spans are ever recorded or exported.
• BatchSpanProcessor + OTLPTraceExporter are now always constructed regardless of enabled, which is a minor style concern — the exporter defaults to http://localhost:4318/v1/traces and will be flushed/shut down at process exit even when disabled (see inline comment).
• The comment in apps/ensapi/src/index.ts describing the indexing-status cache warm-up was condensed; behaviour is unchanged.

Confidence Score: 5/5

• Safe to merge; the sampler correctly disables span recording when no endpoint is defined and no data is lost or exported.
• All findings are P2 (unnecessary object allocation). The functional goal — disabling spans when OTEL_EXPORTER_OTLP_ENDPOINT is absent — is correctly achieved by AlwaysOffSampler. The minor style concern about still constructing the exporter does not affect correctness.
• apps/ensapi/src/lib/instrumentation/index.ts — consider conditionally omitting the BatchSpanProcessor when disabled.

Important Files Changed

Filename	Overview
apps/ensapi/src/lib/instrumentation/index.ts	Replaces conditional BatchSpanProcessor with AlwaysOffSampler to gate tracing; exporter is now always instantiated even when disabled, creating a minor unnecessary-allocation concern on shutdown.
apps/ensapi/src/index.ts	Comment-only simplification of the indexing status cache warm-up explanation; no behavioral change.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[sdk.start] --> B{OTEL_EXPORTER_OTLP_ENDPOINT set?}
    B -- yes --> C[AlwaysOnSampler\nspans recorded]
    B -- no  --> D[AlwaysOffSampler\nspans dropped]
    C --> E[BatchSpanProcessor]
    D --> E
    E --> F[OTLPTraceExporter\nalways constructed]
    F -- enabled=true --> G[HTTP POST to OTLP endpoint]
    F -- enabled=false --> H[No spans reach exporter\n queue always empty]

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_{Reviews (1): Last reviewed commit: "Merge branch 'main' into fix/noop-spans" | Re-trigger Greptile}

[Copilot]

Pull request overview

Updates ENSApi’s OpenTelemetry setup so tracing can be effectively disabled when OTEL_EXPORTER_OTLP_ENDPOINT is not provided, reducing span creation overhead in non-instrumented deployments.

Changes:

• Add an enabled flag derived from OTEL_EXPORTER_OTLP_ENDPOINT and use it to switch between AlwaysOnSampler / AlwaysOffSampler.
• Refactor OTel debug logging toggle into a debug boolean.
• Simplify the startup cache-warming comment in the main server entrypoint.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
apps/ensapi/src/lib/instrumentation/index.ts	Introduces endpoint-driven enable/disable behavior via sampler configuration and refactors tracing setup.
apps/ensapi/src/index.ts	Comment-only change clarifying cache warm-up at startup.

---

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

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

Inline comments:
In `@apps/ensapi/src/lib/instrumentation/index.ts`:
- Around line 27-33: The span processor and exporter (BatchSpanProcessor,
OTLPTraceExporter) are still being instantiated even when telemetry is disabled;
update the instrumentation setup so that when enabled is false you do not
construct BatchSpanProcessor/OTLPTraceExporter — e.g., build spanProcessors as
enabled ? [new BatchSpanProcessor(new OTLPTraceExporter(), {...})] : [] (or
undefined) while keeping sampler: enabled ? new AlwaysOnSampler() : new
AlwaysOffSampler(); this avoids allocating exporter/processor when
AlwaysOffSampler will drop all spans.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

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Run ID: 8f9cec9b-e57f-4173-bf17-f28b884858ed

📥 Commits

Reviewing files that changed from the base of the PR and between 61d76b5 and 6e2c1c0.

📒 Files selected for processing (2)

• apps/ensapi/src/index.ts
• apps/ensapi/src/lib/instrumentation/index.ts