Respect Retry-After in OTLP HTTP senders

[ADITYA-CODE-SOURCE]

Summary:

• honor OTLP/HTTP Retry-After headers in the OkHttp and JDK HTTP senders
• support both delay-seconds and RFC1123 HTTP-date values, with existing exponential backoff as the fallback
• add shared parser coverage plus sender and OTLP integration tests for seconds/date/malformed cases

Fixes #8449

Testing:

• ./gradlew :exporters:common:test --tests "*RetryUtilTest"
• ./gradlew :exporters:sender:okhttp:test --tests "*RetryInterceptorTest"
• ./gradlew :exporters:sender:jdk:test --tests "*JdkHttpSenderTest"
• ./gradlew :exporters:otlp:all:testOkHttpVersionLATEST --tests "OtlpHttp"
• ./gradlew :exporters:otlp:all:testJdkHttpSender --tests "OtlpHttp"
• ./gradlew :exporters:common:spotlessCheck :exporters:sender:okhttp:spotlessCheck :exporters:sender:jdk:spotlessCheck :exporters:otlp:testing-internal:spotlessCheck :exporters:otlp:all:spotlessCheck :exporters:otlp:all:checkstyleTestOkHttpVersionLATEST :exporters:otlp:all:checkstyleTestJdkHttpSender

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: ADITYA-CODE-SOURCE / name: Aditya Vishe (675f3c9)

[codecov]

Codecov Report

❌ Patch coverage is 95.45455% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.47%. Comparing base (b86f040) to head (8cd225a).
⚠️ Report is 17 commits behind head on main.

Files with missing lines	Patch %	Lines
...ry/exporter/sender/jdk/internal/JdkHttpSender.java	88.88%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8633      +/-   ##
============================================
- Coverage     91.60%   91.47%   -0.14%     
- Complexity    10343    10466     +123     
============================================
  Files          1013     1021       +8     
  Lines         27352    27679     +327     
  Branches       3215     3246      +31     
============================================
+ Hits          25057    25318     +261     
- Misses         1567     1617      +50     
- Partials        728      744      +16     

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Waiting on the author · refreshed 2026-07-29 01:36 UTC

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[ADITYA-CODE-SOURCE]

@jack-berg I pushed a follow-up in 8cd225ad addressing the review feedback.

This update:

• honors Retry-After for any retryable HTTP status code
• clamps JDK retry sleep to the remaining timeout budget
• moves parsing edge cases into RetryUtilTest
• trims the higher-level HTTP exporter coverage
• reduces the extra constructor/test seams

Could you please take another look?

[jack-berg]

Just a couple more minor comments. Looks pretty good!

[jack-berg]

The tests in here are perfect candidates for a parameterized test.

[jack-berg]

Is there any observable different between this malformed case and the retryableError_retryAfterHonored case? For example, Could we configure the retry policy min / max backoff in a way that makes it clear when the time from the policy is being used vs the time in the Retry-After header?