# OpenTelemetry C++

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The C++ [OpenTelemetry](https://opentelemetry.io/) client.

## Project Status

| Signal  | Status                  | Project                                                                  |
| ------- | ----------------------- | ------------------------------------------------------------------------ |
| Traces  | Public Release          | N/A                                                                      |
| Metrics | Release Candidate [1,2] | N/A                                                                      |
| Logs    | Experimental [3]        | N/A                                                                      |

* [1]: The metric implementation is in release candidate phase. There would be
      few iterations of new feature additions, and bug fixes before it is
      publically available. Few breaking changes in API and SDK are expected.
* [2]: The earlier implementation (based on old
      specification) is now deprecated, and would be removed once new implementation
      is declared stable. The older implementation can be included in build by setting
      `ENABLE_METRICS_PREVIEW` preprocessor macro, and is included under
      `*/_metrics/*` directory.
* [3]: The current Log Signal Implementation is Experimental, and will change as
      the current OpenTelemetry Log specification matures. The current
      implementation can be included in build by setting `ENABLE_LOGS_PREVIEW`
      preprocessor macro.

## OpenTelemetry Specification Compatibility Matrix

| API Version | Core Version | Contrib Version [1]     |
| ----------- |--------------|-------------------------|
| 1.0.0       | 1.0.0-rc4    | N/A                     |
| 1.0.0       | 1.0.0        | N/A                     |
| 1.9.0       | 1.6.0        | N/A                     |

* [1]: We don't have releases for opentelemetry-cpp contrib repo. This may
      change in future.

## Supported C++ Versions

Code shipped from this repository generally supports the following versions of
C++ standards:

* ISO/IEC 14882:2011 (C++11, C++0x)
* ISO/IEC 14882:2014 (C++14, C++1y)
* ISO/IEC 14882:2017 (C++17, C++1z)
* ISO/IEC 14882:2020 (C++20)

Any exceptions to this are noted in the individual `README.md` files.

Please note that supporting the [C Programming
Language](https://en.wikipedia.org/wiki/C_(programming_language)) is not a goal
of the current project.

## Supported Development Platforms

 Our CI pipeline builds and tests on following `x86-64` platforms:

| Platform                                                            |   Build type  |
|---------------------------------------------------------------------|---------------|
| ubuntu-20.04 (Default GCC Compiler - 9.3.0)                         | CMake, Bazel  |
| ubuntu-18.04 (GCC 4.8 with -std=c++11 flag)                         | CMake [1]     |
| ubuntu-20.04 (Default GCC Compiler - 9.3.0 with -std=c++20 flags)   | CMake, Bazel  |
| macOS 10.15 (Xcode 12.2)                                            | Bazel         |
| Windows Server 2019 (Visual Studio Enterprise 2019)                 | CMake, Bazel  |

[1]: Bazel build is disabled for GCC 4.8, as gRPC library 1.38 and above
  (required by OTLP expoter) don't build with this compiler. See gRPC [official
  support](https://grpc.io/docs/#official-support) document. CMake build doesn't
  build OTLP exporter with GCC 4.8.

In general, the code shipped from this repository should build on all platforms
having C++ compiler with [supported C++ standards](#supported-c-versions).

## Dependencies

Please refer to [Dependencies.md](docs/dependencies.md) for OSS Dependencies and
license requirements.

## Installation

Please refer to [INSTALL.md](./INSTALL.md).

## Getting Started

As an application owner or the library author, you can find the getting started
guide and reference documentation on
[opentelemetry-cpp.readthedocs.io](https://opentelemetry-cpp.readthedocs.io/en/latest/)

The `examples/simple` directory contains a minimal program demonstrating how to
instrument a small library using a simple `processor` and console `exporter`,
along with build files for CMake and Bazel.

## Contributing

See [CONTRIBUTING.md](CONTRIBUTING.md)

We meet weekly, and the time of the meeting alternates between Monday at 13:00
PT and Wednesday at 9:00 PT. The meeting is subject to change depending on
contributors' availability. Check the [OpenTelemetry community
calendar](https://calendar.google.com/calendar/embed?src=google.com_b79e3e90j7bbsa2n2p5an5lf60%40group.calendar.google.com)
for specific dates and Zoom meeting links.

Meeting notes are available as a public [Google
doc](https://docs.google.com/document/d/1i1E4-_y4uJ083lCutKGDhkpi3n4_e774SBLi9hPLocw/edit?usp=sharing).
For edit access, get in touch on
[Slack](https://cloud-native.slack.com/archives/C01N3AT62SJ).

[Maintainers](https://github.com/open-telemetry/community/blob/main/community-membership.md#maintainer)
([@open-telemetry/cpp-maintainers](https://github.com/orgs/open-telemetry/teams/cpp-maintainers)):

* [Ehsan Saei](https://github.com/esigo)
* [Lalit Kumar Bhasin](https://github.com/lalitb), Microsoft
* [Tom Tan](https://github.com/ThomsonTan), Microsoft

[Approvers](https://github.com/open-telemetry/community/blob/main/community-membership.md#approver)
([@open-telemetry/cpp-approvers](https://github.com/orgs/open-telemetry/teams/cpp-approvers)):

* [Josh Suereth](https://github.com/jsuereth), Google
* [Reiley Yang](https://github.com/reyang), Microsoft
* [WenTao Ou](https://github.com/owent), Tencent

[Emeritus
Maintainer/Approver/Triager](https://github.com/open-telemetry/community/blob/main/community-membership.md#emeritus-maintainerapprovertriager):

* [Alolita Sharma](https://github.com/alolita)
* [Emil Mikulic](https://github.com/g-easy)
* [Jodee Varney](https://github.com/jodeev)
* [Johannes Tax](https://github.com/pyohannes)
* [Max Golovanov](https://github.com/maxgolov)
* [Ryan Burn](https://github.com/rnburn)

### Thanks to all the people who have contributed

[![contributors](https://contributors-img.web.app/image?repo=open-telemetry/opentelemetry-cpp)](https://github.com/open-telemetry/opentelemetry-cpp/graphs/contributors)

## Release Schedule

Refer to [project status](#project-status) for current status of the project.

See the [release
notes](https://github.com/open-telemetry/opentelemetry-cpp/releases) for
existing releases.

See the [project
milestones](https://github.com/open-telemetry/opentelemetry-cpp/milestones) for
details on upcoming releases. The dates and features described in issues and
milestones are estimates, and subject to change.
