php/vendor/topthink/think-swoole/src/middleware/TraceRpcClient.php

<?php

namespace think\swoole\middleware;

use think\swoole\exception\RpcResponseException;
use think\swoole\rpc\Protocol;
use think\tracing\Tracer;
use Throwable;
use const OpenTracing\Formats\TEXT_MAP;
use const OpenTracing\Tags\ERROR;
use const OpenTracing\Tags\SPAN_KIND;
use const OpenTracing\Tags\SPAN_KIND_RPC_CLIENT;

class TraceRpcClient
{
    protected $tracer;

    public function __construct(Tracer $tracer)
    {
        $this->tracer = $tracer;
    }

    public function handle(Protocol $protocol, $next)
    {
        $scope   = $this->tracer->startActiveSpan(
            'rpc.client:' . $protocol->getInterface() . '@' . $protocol->getMethod(),
            [
                'tags' => [
                    SPAN_KIND => SPAN_KIND_RPC_CLIENT,
                ],
            ]
        );
        $span    = $scope->getSpan();
        $context = $protocol->getContext();
        $this->tracer->inject($span->getContext(), TEXT_MAP, $context);
        $protocol->setContext($context);

        try {
            return $next($protocol);
        } catch (Throwable $e) {
            if (!$e instanceof RpcResponseException) {
                $span->setTag(ERROR, $e);
            }
            throw $e;
        } finally {
            $scope->close();
        }
    }
}