Sourced from opentelemetry_sdk's changelog.

Release Notes 0.33

The OTLP exporters for Logs and Metrics remain in release-candidate (RC) status in OpenTelemetry Rust 0.33.0. We intend to declare them stable in 0.33.1, approximately two weeks after this release, provided the RC period does not uncover any issues requiring breaking API changes. During this period, we expect only compatible fixes, documentation updates, and low-risk internal optimisations.

OpenTelemetry Rust 0.33.0 brings OTLP retries on by default and completes the stabilisation cleanups that began in 0.32. The Logs and Metrics API and SDK remain stable with no breaking changes. The Distributed Tracing API, SDK, and OTLP exporter remain pre-stable, and this release includes intentional breaking changes in that area to continue preparing it for stabilisation.

For detailed changelogs of individual crates, refer to their respective changelog files. This document summarises the key changes.

Key Changes

OTLP Exporters for Logs and Metrics (RC)

Version 0.33.0 keeps the OTLP exporters for Logs and Metrics in RC for a final validation period. If no issues requiring breaking API changes are identified, we intend to declare them stable in 0.33.1 approximately two weeks after this release.

Retries enabled by default

OTLP/HTTP and OTLP/gRPC retries are now enabled by default with exponential backoff, jitter, and up to 3 retries (4 attempts total). Use .with_retry_policy(RetryPolicy::disabled()) to opt out, or provide a custom RetryPolicy.

Users of the experimental retry feature flags (experimental-grpc-retry and experimental-http-retry) should remove them from Cargo.toml. The retry and retry_classification modules are now crate-private; replace opentelemetry_otlp::retry imports with opentelemetry_otlp::RetryPolicy and use its with_* methods instead of struct literals.

Stabilisation cleanups

• Breaking for callers matching or constructing removed build-error variants: ExporterBuildError now has two exhaustive variants, InvalidConfiguration(String) and InternalFailure(String). Update uses of removed variants. Normal exporter builder calls and propagation of build errors with ? need no changes. See the OTLP changelog for migration examples.
• Breaking Protocol and Compression are now #[non_exhaustive]. Exhaustive matches must add a wildcard arm.
• Breaking Protocol::from_env() is now crate-private. Builders resolve OTEL_EXPORTER_OTLP_PROTOCOL automatically; read the env var directly if needed.
• Invalid OTLP endpoint environment variables (HTTP and gRPC) now produce a

... (truncated)

• 1983384 docs: clarify OTLP 0.33 migration guidance (#3747)
• dacfeda chore: Prepare for release v0.33.0 (RC) (#3712)
• 996ac1e refactor(http)!: make ResponseBodyTooLarge extensible (#3736)
• d328c65 fix(proto): preserve scope metadata when grouping OTLP logs (#3740)
• e652efd refactor(otlp): finalize exporter build error API (#3692)
• 8809c42 refactor(otlp)!: separate configuration parsing errors (#3742)
• cc1c374 feat(otlp): Allow to provide http client wrapped in Arc for user (#3468)
• e085c61 ci: use supported Debian image for benchmarks (#3744)
• 6c5fd58 fix(proto): accept omitted partial success fields (#3739)
• 51b36a7 fix(otlp): handle enum environment values consistently (#3730)
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