64 lines
2.4 KiB
Markdown
64 lines
2.4 KiB
Markdown
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[](https://github.com/opentelemetry-php/context/releases)
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[](https://github.com/open-telemetry/opentelemetry-php/tree/main/src/Context)
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[](https://github.com/opentelemetry-php/context)
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[](https://packagist.org/packages/open-telemetry/context/)
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[](https://packagist.org/packages/open-telemetry/context/)
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# OpenTelemetry Context
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Immutable execution scoped propagation mechanism, for further details see [opentelemetry-specification][1].
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## Installation
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```shell
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composer require open-telemetry/context
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```
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## Usage
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### Implicit propagation
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```php
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$context = Context::getCurrent();
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// modify context
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$scope = $context->activate();
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try {
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// run within new context
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} finally {
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$scope->detach();
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}
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```
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It is recommended to use a `try-finally` statement after `::activate()` to ensure that the created scope is properly `::detach()`ed.
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## Async applications
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### Fiber support
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Requires `PHP >= 8.1`, an NTS build, `ext-ffi`, and setting the environment variable `OTEL_PHP_FIBERS_ENABLED` to a truthy value. Additionally `vendor/autoload.php` has to be preloaded for non-CLI SAPIs if [`ffi.enable`](https://www.php.net/manual/en/ffi.configuration.php#ini.ffi.enable) is set to `preload`.
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### Event loops
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Event loops have to restore the original context on callback execution. A basic implementation could look like the following, though implementations should avoid keeping unnecessary references to arguments if possible:
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```php
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function bindContext(Closure $closure): Closure {
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$context = Context::getCurrent();
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return static function (mixed ...$args) use ($closure, $context): mixed {
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$scope = $context->activate();
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try {
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return $closure(...$args);
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} finally {
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$scope->detach();
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}
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};
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}
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```
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## Contributing
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This repository is a read-only git subtree split.
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To contribute, please see the main [OpenTelemetry PHP monorepo](https://github.com/open-telemetry/opentelemetry-php).
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[1]: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/context/README.md#context
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