refactor!(otlp-grpc-exporter-base): remove headers from gRPC config type by pratik50 · Pull Request #6487 · open-telemetry/opentelemetry-js

pratik50 · 2026-03-10T16:11:02Z

if you pass headers when using gRPC exporter, it just gets silently ignored. no error, nothing. pretty confusing for users.

turns out OTLPGRPCExporterConfigNode was extending OTLPExporterConfigBase which has headers in it (that's for HTTP only). gRPC doesn't use HTTP headers, it uses metadata instead.

Short description of the changes

removed extends OTLPExporterConfigBase from OTLPGRPCExporterConfigNode
manually added only the fields gRPC actually needs (url, concurrencyLimit, timeoutMillis)
removed the diag.warn for headers since TS will catch it at compile time now

all 3 exporters (trace, metrics, logs) import this type from base so they're all fixed with this one change

Type of change

Breaking change

passing headers will now be a TS compile error instead of silently doing nothing. i think this is fine since it was never actually working anyway users should use metadata for gRPC

How Has This Been Tested?

existing tests for all packages pass:

otlp-grpc-exporter-base
exporter-trace-otlp-grpc
opentelemetry-exporter-metrics-otlp-grpc
exporter-logs-otlp-grpc

Checklist:

Followed the style guidelines of this project
Unit tests pass
Documentation has been updated

…emove-headers

dyladan

Nothing against the actual code change but the CHANGELOG entry is wrong and package-lock is unnecessarily changed.

dyladan · 2026-03-10T17:59:58Z

Unrelated change

dyladan · 2026-03-10T18:06:47Z

 * fix(opentelemetry-instrumentation): improve `_warnOnPreloadedModules` function not to show warning logs when the module is not marked as loaded [#6095](https://github.com/open-telemetry/opentelemetry-js/pull/6095) @rlj1202
 * fix(sdk-trace-base): derive internal `SpanOptions` from API type to prevent drift [#6478](https://github.com/open-telemetry/opentelemetry-js/pull/6478) @overbalance
-* fix(span): enforce `attributePerEventCountLimit`, `attributePerLinkCountLimit`, `linkCountLimit`, and `attributeValueLengthLimit` for event/link attributes [#6479](https://github.com/open-telemetry/opentelemetry-js/pull/6479) @overbalance
+* fix(otlp-grpc-exporter-base): remove `headers` from gRPC exporter config type, passing headers now results in a compile-time error instead of being silently ignored [#6487](https://github.com/open-telemetry/opentelemetry-js/pull/6487)


This is in the wrong place and replaces an existing entry rather than creating a new one. This should be under the :breaking: header in experimental/CHANGELOG.md. It is also not a bugfix so i'd consider switching this to be a refactor! type.

pratik50 · 2026-03-10T22:13:04Z

@dyladan thanks for the review!
Fixed both moved the CHANGELOG entry to experimental/CHANGELOG.md under boom: Breaking Changes and reverted the package-lock.json changes.

dyladan · 2026-03-11T00:44:13Z


 * fix(opentelemetry-instrumentation): improve `_warnOnPreloadedModules` function not to show warning logs when the module is not marked as loaded [#6095](https://github.com/open-telemetry/opentelemetry-js/pull/6095) @rlj1202
 * fix(sdk-trace-base): derive internal `SpanOptions` from API type to prevent drift [#6478](https://github.com/open-telemetry/opentelemetry-js/pull/6478) @overbalance
-* fix(span): enforce `attributePerEventCountLimit`, `attributePerLinkCountLimit`, `linkCountLimit`, and `attributeValueLengthLimit` for event/link attributes [#6479](https://github.com/open-telemetry/opentelemetry-js/pull/6479) @overbalance


Revert this unintended change

dyladan · 2026-03-11T00:47:20Z

+  url?: string;
+  concurrencyLimit?: number;
+  timeoutMillis?: number;


These typically come from OTLPExporterConfigBase. If they're removed here we risk them becoming out of sync. It would be better to remove the bad header property from the base and add it specifically to the HTTP exporters. Alternatively you could use Omit<T, K> to remove it from the parent class before using it here.

Switched to Omit<OTLPExporterConfigBase, 'headers'> and All tests passed. Pls review it.

hmm, IMO it's a positive thing that they diverge:

they're different exporters and the same options (url in particular) behave differently based on whether they're used for gRPC or http, which makes them hard to document.

we also don't consume OTLPGRPCExporterConfigNode as OTLPExporterConfigBase anywhere anymore.

it makes it less likely that things are added to the base that unintentionally get added to the gRPC exporter's public API which can confuse users (like what happened to headers in this case).

That makes sense! So should I revert back to the original approach (manually listing the fields with TS types) and drop the Omit change?

We can do that in a follow up PR, your current change addresses what the linked issue was about. :)

codecov · 2026-03-11T02:12:52Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.73%. Comparing base (de02086) to head (6241597).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6487   +/-   ##
=======================================
  Coverage   95.73%   95.73%           
=======================================
  Files         364      364           
  Lines       11826    11826           
  Branches     2765     2765           
=======================================
  Hits        11322    11322           
  Misses        504      504

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
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…RPC config

pichlermarc

I'm okay with the current change % this blocking comment, as the current change addresses the original intent of the linked issue.

We can discuss not having OTLPGRPCExporterConfigNode extend OTLPExporterConfigBase in a follow-up, but it's not necessary to do right now.

pratik50 · 2026-03-11T11:52:34Z

All issues fixed, ready for re-review!

otelbot · 2026-03-11T13:02:50Z

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fix(otlp-grpc-exporter-base): remove headers from gRPC config type

05de16b

pratik50 requested a review from a team as a code owner March 10, 2026 16:11

pratik50 added 3 commits March 10, 2026 22:01

chore: fix lint and update CHANGELOG

a9356c7

Merge remote-tracking branch 'upstream/main' into fix/grpc-exporter-r…

f45ce74

…emove-headers

resolve merge conflict with upstream/main

d462ed7

dyladan requested changes Mar 10, 2026

View reviewed changes

fix CHANGELOG entries and proper package-lock.json

6b10bfa

dyladan requested changes Mar 11, 2026

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refactor(otlp-grpc-exporter-base): use Omit to exclude headers from g…

dff2829

…RPC config

pichlermarc reviewed Mar 11, 2026

View reviewed changes

chore: restore accidentally deleted CHANGELOG entry

6241597

pichlermarc approved these changes Mar 11, 2026

View reviewed changes

pichlermarc requested a review from dyladan March 11, 2026 11:56

dyladan approved these changes Mar 11, 2026

View reviewed changes

dyladan added this pull request to the merge queue Mar 11, 2026

dyladan changed the title ~~fix(otlp-grpc-exporter-base): remove headers from gRPC config type~~ refactor!(otlp-grpc-exporter-base): remove headers from gRPC config type Mar 11, 2026

github-merge-queue Bot removed this pull request from the merge queue due to failed status checks Mar 11, 2026

dyladan added this pull request to the merge queue Mar 11, 2026

Merged via the queue into open-telemetry:main with commit 17e9f91 Mar 11, 2026
27 checks passed

otelbot-js Bot mentioned this pull request Mar 20, 2026

chore: prepare next release #6510

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pratik50 mentioned this pull request Mar 31, 2026

REQUEST: New membership for pratik50 open-telemetry/community#3349

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pratik50 commented Mar 10, 2026

Short description of the changes

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