thesis/opentelemetry-grpc-transport

A gRPC transport for opentelemetry-php built on thesis/grpc-client: a drop-in replacement for open-telemetry/transport-grpc that needs no ext-grpc, because the whole gRPC stack — HTTP/2 framing, compression, TLS, load balancing — is plain PHP running on amphp.

Contents

• Installation
• Usage
• Configuration
• Bringing your own client
• Example

Installation

composer require thesis/opentelemetry-grpc-transport

Usage

TransportFactory implements TransportFactoryInterface, so it plugs into any OTLP exporter in place of the one shipped by the contrib package. The endpoint is a URL whose path is the fully qualified gRPC method of the signal:

use OpenTelemetry\API\Signals;
use OpenTelemetry\Contrib\Otlp\OtlpUtil;
use OpenTelemetry\Contrib\Otlp\SpanExporter;
use Thesis\OpenTelemetry\Grpc\TransportFactory;

$transport = new TransportFactory()->create(
    'http://collector:4317' . OtlpUtil::method(Signals::TRACE),
);

$exporter = new SpanExporter($transport);

Bringing your own client

The factory only applies what OTLP knows about. Load balancing, endpoint resolvers, connection limits and your own interceptors belong on a Client\Builder, which the factory takes as a constructor argument, leaves untouched and reuses for every transport it creates:

use Thesis\Grpc\Client;
use Thesis\OpenTelemetry\Grpc\TransportFactory;

$factory = new TransportFactory(
    new Client\Builder()
        ->withLoadBalancer(new Client\LoadBalancer\RoundRobinFactory())
        ->withConnectionLimit(4),
);

The host, the encoder, the retry interceptor, compression and TLS are set by the factory on top of it and override whatever the builder had for those.

Example

examples/otlp_grpc.php exports a handful of spans to a collector. A Jaeger all-in-one is defined in compose.yaml behind the example profile, so one target brings it up and runs the example against it:

make example

The spans then show up at http://localhost:16686 under the unknown_service:php service.

Against a collector you are running yourself:

OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4317 php examples/otlp_grpc.php

It needs open-telemetry/exporter-otlp for the exporter itself.