# PHP
> 
A language-specific implementation of OpenTelemetry in PHP.
---
这是 OpenTelemetry PHP 的文档。 OpenTelemetry 是一个可观测性框架，这个框架提供了
API、SDK 以及一系列工具，用于辅助生成以及收集应用的遥测数据，比如链路、指标、日志。
通过本文档，你将了解如何开始使用 OpenTelemetry PHP。
## 状态以及版本发布 {#status-and-releases}
OpenTelemetry PHP 的当前主要功能组件状态如下：
| 链路 | 指标 | 日志 |
| ------------------- | -------------------- | ----------------- |
| [Stable](/docs/specs/otel/versioning-and-stability/#stable) | [Stable](/docs/specs/otel/versioning-and-stability/#stable) | [Stable](/docs/specs/otel/versioning-and-stability/#stable) |
我们可以在 [Releases][] 中找到所有已发布的版本，包括[最新发布的版本][latest release]。
[latest release]:
[Releases]:
{{__hugo_ctx/}}
## Further Reading
- [OpenTelemetry for PHP on GitHub](https://github.com/open-telemetry/opentelemetry-php)
- [Examples](https://github.com/open-telemetry/opentelemetry-php/tree/main/examples)
## Requirements
OpenTelemetry SDK for PHP aims to support all officially supported PHP versions
according to
[www.php.net/supported-versions](https://www.php.net/supported-versions.php),
and support will be dropped for PHP versions within 12 months of that version
going End of Life.
Auto-instrumentation requires PHP version 8.0+.
### Dependencies
Some of the `SDK` and `Contrib` packages have a dependency on both a
[HTTP Factories (PSR-17)](https://www.php-fig.org/psr/psr-17/) and a
[php-http/async-client](https://docs.php-http.org/en/latest/clients.html)
implementation. You can find appropriate composer packages implementing given
standards on [packagist.org](https://packagist.org/).
See
[http-factory-implementations](https://packagist.org/providers/psr/http-factory-implementation)
to find a `PSR-17 (HTTP factories)` implementation, and
[async-client-implementations](https://packagist.org/providers/php-http/async-client-implementation)
to find a `php-http/async-client` implementation.
### Optional PHP extensions
| Extension | Purpose |
| ------------------------------------------------------------------------- | ----------------------------------------------------------------- |
| [ext-grpc](https://github.com/grpc/grpc/tree/master/src/php) | Required to use gRPC as a transport for the OTLP exporter |
| [ext-mbstring](https://www.php.net/manual/en/book.mbstring.php) | More performant than the fallback, `symfony/polyfill-mbstring` |
| [ext-zlib](https://www.php.net/manual/en/book.zlib.php) | If you want to compress exported data |
| [ext-ffi](https://www.php.net/manual/en/book.ffi.php) | Fiber-based context storage |
| [ext-protobuf](https://github.com/protocolbuffers/protobuf/tree/main/php) | _Significant_ performance improvement for otlp+protobuf exporting |
#### ext-ffi
Fibers support can be enabled by setting the `OTEL_PHP_FIBERS_ENABLED`
environment variable to `true`. Using fibers with non-`CLI` SAPIs may require
preloading of bindings. One way to achieve this is setting
[`ffi.preload`](https://www.php.net/manual/en/ffi.configuration.php#ini.ffi.preload)
to `src/Context/fiber/zend_observer_fiber.h` and setting
[`opcache.preload`](https://www.php.net/manual/en/opcache.preloading.php) to
`vendor/autoload.php`.
#### ext-protobuf
The [native protobuf library](https://packagist.org/packages/google/protobuf) is
significantly slower than the extension. We strongly encourage the use of the
extension.
## Setup
OpenTelemetry for PHP is distributed via
[packagist](https://packagist.org/packages/open-telemetry/), in a number of
packages. We recommend that you install only the packages that you need, which
as a minimum is usually `API`, `Context`, `SDK` and an exporter.
We strongly encourage that your code only depend on classes and interfaces in
the `API` package.
---
Section pages:
- [Getting Started](/zh/docs/languages/php/getting-started/): Get up and running with OpenTelemetry for PHP.
- [Instrumentation](/zh/docs/languages/php/instrumentation/): Manual instrumentation for OpenTelemetry PHP
- [Using instrumentation libraries](/zh/docs/languages/php/libraries/)
- [Exporters](/zh/docs/languages/php/exporters/)
- [Context](/zh/docs/languages/php/context/): Learn how the context API works in instrumented applications.
- [Propagation](/zh/docs/languages/php/propagation/): Context propagation for the PHP API
- [Resources](/zh/docs/languages/php/resources/)
- [SDK](/zh/docs/languages/php/sdk/)
- [API reference](/zh/docs/languages/php/api/)
- [Examples](/zh/docs/languages/php/examples/)
- [Registry](/zh/docs/languages/php/registry/): Instrumentation libraries, exporters and other useful components for OpenTelemetry PHP