Exporters
In order to visualize and analyze your telemetry, you will need to export your data to an OpenTelemetry Collector or a backend such as Jaeger, Zipkin, Prometheus or a vendor-specific one.
As part of OpenTelemetry PHP you will find many exporters being available. Among them, the OpenTelemetry Protocol (OTLP) exporters provide the best experience for you as an end-user, since it is a general-purpose telemetry data delivery protocol designed in the scope of the OpenTelemetry project.
To learn more about the OTLP protocol, you can read the OTLP Specification.
Below you will find some introductions on how to set up exporters for OTLP and other common protocols in your code.
OTLP
要将跟踪数据发送到OTLP端点（例如收集器或Jaeger），您需要使用open-telemetry/exporter-otlp包和满足psr/http-client-implementation的HTTP客户端：
composer require \
open-telemetry/exporter-otlp \
php-http/guzzle7-adapter
要使用gRPC导出器，您还需要安装open-telemetry/transport-grpc包和grpc扩展：
pecl install grpc
composer require open-telemetry/transport-grpc
接下来，使用OTLP端点配置一个导出器。例如：
<?php
require __DIR__ . '/vendor/autoload.php';
use OpenTelemetry\API\Common\Signal\Signals;
use OpenTelemetry\Contrib\Grpc\GrpcTransportFactory;
use OpenTelemetry\Contrib\Otlp\OtlpUtil;
use OpenTelemetry\Contrib\Otlp\SpanExporter;
use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
use OpenTelemetry\SDK\Trace\TracerProvider;
$transport = (new GrpcTransportFactory())->create('http://jaeger:4317' . OtlpUtil::method(Signals::TRACE));
$exporter = new SpanExporter($transport);
$tracerProvider = new TracerProvider(
new SimpleSpanProcessor($exporter)
);
<?php
require __DIR__ . '/vendor/autoload.php';
use OpenTelemetry\Contrib\Otlp\OtlpHttpTransportFactory;
use OpenTelemetry\Contrib\Otlp\SpanExporter;
use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
use OpenTelemetry\SDK\Trace\TracerProvider;
$transport = (new OtlpHttpTransportFactory())->create('http://jaeger:4318/v1/traces', 'application/x-protobuf');
$exporter = new SpanExporter($transport);
$tracerProvider = new TracerProvider(
new SimpleSpanProcessor($exporter)
);
<?php
require __DIR__ . '/vendor/autoload.php';
use OpenTelemetry\Contrib\Otlp\OtlpHttpTransportFactory;
use OpenTelemetry\Contrib\Otlp\SpanExporter;
use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
use OpenTelemetry\SDK\Trace\TracerProvider;
$transport = (new OtlpHttpTransportFactory())->create('http://jaeger:4318/v1/traces', 'application/json');
$exporter = new SpanExporter($transport);
$tracerProvider = new TracerProvider(
new SimpleSpanProcessor($exporter)
);
$tracer = $tracerProvider->getTracer('io.opentelemetry.contrib.php');
$tracer->spanBuilder('example')->startSpan()->end();
<?php
require __DIR__ . '/vendor/autoload.php';
use OpenTelemetry\Contrib\Otlp\OtlpHttpTransportFactory;
use OpenTelemetry\Contrib\Otlp\SpanExporter;
use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
use OpenTelemetry\SDK\Trace\TracerProvider;
$transport = (new OtlpHttpTransportFactory())->create('http://jaeger:4318/v1/traces', 'application/x-ndjson');
$exporter = new SpanExporter($transport);
$tracerProvider = new TracerProvider(
new SimpleSpanProcessor($exporter)
);
$tracer = $tracerProvider->getTracer('io.opentelemetry.contrib.php');
$tracer->spanBuilder('example')->startSpan()->end();
然后，附加以下代码以生成一个跟踪：
$tracer = $tracerProvider->getTracer('io.opentelemetry.contrib.php');
$tracer
->spanBuilder('example')
->startSpan()
->end();
要尝试上面的示例，您可以在Docker容器中运行Jaeger：
docker run -d --name jaeger \
-e COLLECTOR_ZIPKIN_HOST_PORT=:9411 \
-e COLLECTOR_OTLP_ENABLED=true \
-p 6831:6831/udp \
-p 6832:6832/udp \
-p 5778:5778 \
-p 16686:16686 \
-p 4317:4317 \
-p 4318:4318 \
-p 14250:14250 \
-p 14268:14268 \
-p 14269:14269 \
-p 9411:9411 \
jaegertracing/all-in-one:latest
Zipkin
如果您正在使用Zipkin来可视化跟踪，您首先需要进行设置。以下是在本地Docker容器中运行它的方法。
docker run --rm -d -p 9411:9411 --name zipkin openzipkin/zipkin
将导出器包作为应用程序的依赖项进行安装：
composer require open-telemetry/exporter-zipkin
更新示例以使用Zipkin导出器并将数据发送到您的Zipkin后端：
$transport = \OpenTelemetry\SDK\Common\Export\Http\PsrTransportFactory::discover()
->create('http://zipkin:9411/api/v2/spans', 'application/json');
$zipkinExporter = new ZipkinExporter($transport);
$tracerProvider = new TracerProvider(
new SimpleSpanProcessor($zipkinExporter)
);
$tracer = $tracerProvider->getTracer('io.opentelemetry.contrib.php');
降低导出延迟
大多数PHP运行时是同步和阻塞的。发送遥测数据可能会延迟HTTP响应到达用户。
如果您使用fastcgi，您可以在发送用户响应后发出调用fastcgi_finish_request()，这意味着延迟发送遥测数据不会阻塞请求处理。
为了最大限度地减少慢速传输遥测数据的影响，特别是针对外部或基于云的后端，您应该考虑使用OpenTelemetry收集器作为代理。收集器可以快速接收并批量发送遥测数据到后端。