[SDK] Read span limits from environment variables#4258
Open
HrMathematiker wants to merge 4 commits into
Open
Conversation
HrMathematiker
marked this pull request as ready for review
July 16, 2026 16:29
HrMathematiker
force-pushed
the
span-limits-env
branch
from
July 16, 2026 16:32
3184ec8 to
25b7940
Compare
Contributor
|
@HrMathematiker thanks for the contribution. Please take a look on the missing CLA authorization. |
HrMathematiker
force-pushed
the
span-limits-env
branch
from
July 17, 2026 07:39
3c5e3ca to
2578631
Compare
Member
|
Thanks for the contribution, this part is really needed in opentelemetry-cpp. Please clear the EasyCLA, merging can not happen without it. |
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #4258 +/- ##
==========================================
+ Coverage 81.19% 81.20% +0.02%
==========================================
Files 444 445 +1
Lines 18880 18902 +22
==========================================
+ Hits 15328 15348 +20
- Misses 3552 3554 +2
🚀 New features to boost your workflow:
|
HrMathematiker
force-pushed
the
span-limits-env
branch
from
July 17, 2026 11:28
972fc04 to
d3c2d3a
Compare
Adds span_limits_env::GetSpanLimitsFromEnv(), which builds a SpanLimits from the environment variables defined in the specification (OTEL_SPAN_ATTRIBUTE_COUNT_LIMIT, OTEL_SPAN_ATTRIBUTE_VALUE_LENGTH_LIMIT, OTEL_SPAN_EVENT_COUNT_LIMIT, OTEL_SPAN_LINK_COUNT_LIMIT, OTEL_EVENT_ATTRIBUTE_COUNT_LIMIT, OTEL_LINK_ATTRIBUTE_COUNT_LIMIT, and the general OTEL_ATTRIBUTE_* fallbacks), and uses it as the default in the TracerProviderFactory::Create overloads that previously defaulted to SpanLimits::NoLimits(). A field whose variable is unset keeps its NoLimits() value, so behavior is unchanged when no variables are set; explicitly passed SpanLimits keep taking precedence.
HrMathematiker
force-pushed
the
span-limits-env
branch
from
July 17, 2026 11:37
d3c2d3a to
1f21f0b
Compare
Author
|
@marcalff the CLI is authorized now :) |
owent
approved these changes
Jul 19, 2026
dbarker
approved these changes
Jul 19, 2026
dbarker
left a comment
dbarker
left a comment
Member
There was a problem hiding this comment.
Looks good to me. Thanks for the contribution. Just optional feedback below.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
5 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Fixes #4257
Changes
Adds
span_limits_env::GetSpanLimitsFromEnv(), which builds aSpanLimitsfrom the environment variables defined in the specification, and uses it as the default in theTracerProviderFactory::Createoverloads that previously defaulted toSpanLimits::NoLimits(). The implementation mirrors the existingbatch_span_processor_options_envpattern (OTEL_BSP_*).Semantics, chosen to preserve the backward-compatible default established in #4232:
SpanLimits::NoLimits()value — with no variables set,GetSpanLimitsFromEnv() == SpanLimits::NoLimits()and SDK behavior is unchanged.OTEL_SPAN_ATTRIBUTE_VALUE_LENGTH_LIMIT,OTEL_SPAN_ATTRIBUTE_COUNT_LIMIT,OTEL_SPAN_EVENT_COUNT_LIMIT,OTEL_SPAN_LINK_COUNT_LIMIT,OTEL_EVENT_ATTRIBUTE_COUNT_LIMIT,OTEL_LINK_ATTRIBUTE_COUNT_LIMIT, plus the generalOTEL_ATTRIBUTE_VALUE_LENGTH_LIMIT/OTEL_ATTRIBUTE_COUNT_LIMIT, with the span-specific variables taking precedence per the spec.SpanLimits(programmatic, or declarative configuration through the sdk builder) continue to take precedence over the environment, matching the spec's configuration-precedence order.Follow-up once merged: flip the C++ cells of the span-limit env-variable rows in the spec compliance matrix (separate PR to the specification repo).
For significant contributions please make sure you have completed the following items:
CHANGELOG.mdupdated for non-trivial changes