The Rust special interest group (SIG) meets on alternating weeks between Tuesday at 9:00 AM PT and Wednesday at 8:00 AM PT. The meeting is subject to change depending on contributors' availability. Check the OpenTelemetry community calendar for specific dates and for Zoom meeting links. "OTel Rust SIG" is the name of meeting for this group.
Meeting notes are available as a public Google doc. If you have trouble accessing the doc, please get in touch on Slack.
The meeting is open for all to join. We invite everyone to join our meeting, regardless of your experience level. Whether you're a seasoned OpenTelemetry developer, just starting your journey, or simply curious about the work we do, you're more than welcome to participate!
Even though, anybody can contribute, there are benefits of being a member of our community. See to the community membership document on how to become a Member, Approver and Maintainer.
If you'd like to work on something that isn't already tracked as an issue — whether it's a new feature, enhancement, or significant refactor — please create an issue first and describe your proposal. This gives maintainers a chance to provide feedback on the approach before you invest significant time, and helps avoid situations where a PR doesn't align with the project's direction.
For bug fixes or small improvements to existing functionality, opening a PR directly is fine.
If you're new to the codebase, these docs will help you get oriented:
- Architecture overview — workspace structure, API/SDK separation, and crate responsibilities
- Signal-specific design docs: traces, metrics, logs
- Architectural decision records — context behind past design choices
- Library guidelines from the OpenTelemetry specification
Crate opentelemetry-otlp uses gRPC + Protocol Buffers.
You can provide the protocol compiler protoc path programmatically (only works with tonic) or build it from source
export PROTOC=$(which protoc)It is recommended to use "3.15" or newer of protoc, as some of the proto definitions include "optional" fields, that are not supported in older versions, resulting in errors as shown here.
Prerequisites to build the protocol compiler protoc from source
- protoc
- cmake
- llvm (and
LIBCLANG_PATHenvironment variable pointing to thebindirectory of LLVM install)
Everyone is welcome to contribute code to opentelemetry-rust via
GitHub pull requests (PRs).
git clone --recurse-submodule https://github.com/open-telemetry/opentelemetry-rustEnter the newly created directory and add your fork as a new remote:
git remote add <YOUR_FORK> [email protected]:<YOUR_GITHUB_USERNAME>/opentelemetry-rustCheck out a new branch, make modifications, run linters and tests, and push the branch to your fork:
$ git checkout -b <YOUR_BRANCH_NAME>
# edit files
$ git add -p
$ git commit
$ git push <YOUR_FORK> <YOUR_BRANCH_NAME>Open a pull request against the main opentelemetry-rust repo.
Your pull request should be named according to the
conventional commits standard. This ensures that
when the PR is squashed into main, the resulting commit message is consistent and makes it easier
for us to generate a changelog standard.
Note It is recommended to run pre-commit script to catch any issues locally.
- If the PR is not ready for review, please put
[WIP]in the title or mark it asdraft. - Make sure CLA is signed and all required CI checks are clear.
- Submit small, focused PRs addressing a single concern/issue.
- Make sure the PR title reflects the contribution.
- Write a summary that helps understand the change.
- Include usage examples in the summary, where applicable.
- Include benchmarks (before/after) in the summary, for contributions that are performance enhancements.
We recommend keeping PRs under 500 lines (excluding Cargo.lock and generated
code) to allow thorough and timely reviews. If your change is larger than this,
consider breaking it into incremental PRs — for example:
- First PR: Introduce new types, traits, or structural scaffolding.
- Follow-up PRs: Add the implementation, split further if needed.
- Final PR: Wire everything together and update documentation.
For changes that span multiple signals (traces, metrics, logs), consider starting with a PR that targets just one signal. This lets maintainers review the approach on a smaller surface area and give feedback before you replicate it across all three.
Refactoring must be in its own PR with no behavior changes. Mixing refactoring with new functionality makes it difficult for reviewers to verify correctness and often leads to longer review cycles.
A PR is considered to be ready to merge when:
- It has received approval from Approvers. / Maintainers.
- Major feedbacks are resolved.
Any Maintainer can merge the PR once it is ready to merge. Note, that some PRs may not be merged immediately if the repo is in the process of a release and the maintainers decided to defer the PR to the next release train. Also, maintainers may decide to wait for more than one approval for certain PRs, particularly ones that are affecting multiple areas, or topics that may warrant more discussion.
We use GitHub labels to track issue status and help contributors find work. Understanding these labels will help you know which issues are ready to be worked on and how to find ones that match your experience level.
When creating a new issue, please use one of the provided issue templates (Bug Report or Feature Request). The templates automatically apply triage labels so that maintainers can find and review new issues. Avoid creating blank issues, as they won't have the correct labels and may be overlooked.
Every new issue filed through a template starts with triage:todo. Maintainers
review these and either:
triage:accepted— the issue has been reviewed and is ready to be worked on. If you're looking for something to contribute, start here.triage:needmoreinfo— the issue needs clarification from the reporter before it can be acted on.
Don't start work on an issue that hasn't been triaged. An issue with
triage:todo may be a duplicate, out of scope, or need a different approach
than what's described. Wait for triage:accepted or ask in the issue if you're
interested.
good first issue— scoped issues suitable for newcomers to the codebase. These are a starting point, not a restriction — newcomers are welcome to work on any accepted issue.help wanted— issues where maintainers welcome contributions and will provide extra guidance.
These indicate which part of the codebase an issue relates to:
| Label | Area |
|---|---|
A-trace |
Tracing signal |
A-metrics |
Metrics signal |
A-log |
Logs signal |
A-common |
Cross-cutting / not signal-specific |
These indicate which crate is affected:
| Label | Crate |
|---|---|
M-api |
opentelemetry (API) |
M-sdk |
opentelemetry-sdk |
M-exporter-otlp |
opentelemetry-otlp |
M-exporter-prometheus |
opentelemetry-prometheus |
M-exporter-zipkin |
opentelemetry-zipkin |
| Label | Meaning |
|---|---|
priority:p0 |
Critical stop-the-world issues. Drop everything. |
priority:p1 |
High priority — should be addressed soon. |
priority:p2 |
Medium priority. |
priority:p3 |
Low priority — nice to have. |
These labels are applied to PRs to indicate their semver impact:
| Label | Impact |
|---|---|
version:breaking |
Breaking change (major version bump) |
version:minor |
New functionality (minor version bump) |
version:patch |
Bug fix (patch version bump) |
| Label | Meaning |
|---|---|
S-blocked-spec |
Blocked on an unresolved spec issue |
platform:windows / platform:linux / platform:mac / platform:wasm |
Platform-specific |
performance |
Performance-related |
documentation/examples |
Documentation or examples improvement |
As with other OpenTelemetry clients, opentelemetry-rust follows the opentelemetry-specification.
It's especially valuable to read through the library guidelines.
OpenTelemetry is an evolving specification, one where the desires and use cases are clear, but the method to satisfy those uses cases are not.
As such, Contributions should provide functionality and behavior that conforms to the specification, but the interface and structure is flexible.
It is preferable to have contributions follow the idioms of the language rather than conform to specific API names or argument patterns in the spec.
For a deeper discussion, see: open-telemetry/opentelemetry-specification#165
Currently, the Opentelemetry Rust SDK has two ways to handle errors. In the situation where errors are not allowed to return. One should call global error handler to process the errors. Otherwise, one should return the errors.
The Opentelemetry Rust SDK comes with an error type opentelemetry::Error. For different function, one error has been defined. All error returned by trace module MUST be wrapped in opentelemetry::trace::TraceError. All errors returned by metrics module MUST be wrapped in opentelemetry::metrics::MetricError. All errors returned by logs module MUST be wrapped in opentelemetry::logs::LogsError.
For users that want to implement their own exporters. It's RECOMMENDED to wrap all errors from the exporter into a crate-level error type, and implement ExporterError trait.
OpenTelemetry supports multiple ways to configure the API, SDK and other components. The priority of configurations is as follows:
- Environment variables
- Compiling time configurations provided in the source code
Use otel_unstable feature flag for implementation of specification with experimental status. This approach ensures clear demarcation and safe integration of new or evolving features. Utilize the following structure:
#[cfg(feature = "otel_unstable")]
{
// Your feature implementation
}It's important to regularly review and remove the otel_unstable flag from the code once the feature becomes stable. This cleanup process is crucial to maintain the overall code quality and to ensure that stable features are accurately reflected in the main build.
The potential features include:
- Stable and non-experimental features that are compliant with the specification and have a feature flag to minimize compilation size. Example: feature flags for signals (like
logs,traces,metrics) and runtimes (rt-tokio,rt-tokio-current-thread). - Stable and non-experimental features, although not part of the specification, are crucial for enhancing the tracing/log crate's functionality or boosting performance. These features are also subject to discussion and approval by the OpenTelemetry Rust Maintainers.
All such features should adhere to naming convention <signal>_<feature_name>
- Run
cargo clippy --all- this will catch common mistakes and improve your Rust code - Run
cargo fmt- this will find and fix code formatting issues.
- Run
cargo test --all- this will execute code and doc tests for all projects in this workspace. - Run
cargo bench- this will run benchmarks to show performance regressions
Benchmarks are run daily against main and results are tracked over time.
The continuous benchmark dashboard is published at
https://open-telemetry.github.io/opentelemetry-rust/dev/bench/.
PRs with the performance label will also get a benchmark comparison
comment showing any regressions or improvements.
As of now, the specification classify the propagators into three categories: Fully opened standards, platform-specific standards, proprietary headers. The conclusion is only the fully opened standards should live in SDK packages/repos. So here, only fully opened standards should live as independent crate. For more detail and discussion, see this pr.