purge.php

      $uri = $this->uriFactory->create();
        $socketAdapter = $this->socketAdapterFactory->create();
        $servers = $this->deploymentConfig->get(ConfigOptionsListConstants::CONFIG_PATH_CACHE_HOSTS)
            ?: [['host' => $this->request->getHttpHost()]];
        $headers = ['X-Magento-Tags-Pattern' => $tagsPattern];
        $socketAdapter->setOptions(['timeout' => 10]);
        foreach ($servers as $server) {
            $port = isset($server['port']) ? $server['port'] : self::DEFAULT_PORT;
            $uri->setScheme('http')
                ->setHost($server['host'])
                ->setPort($port);
            try {
                $socketAdapter->connect($server['host'], $port);
                $socketAdapter->write(
                    'PURGE',
                    $uri,
                    '1.1',
                    $headers
                );
                $socketAdapter->close();
            } catch (Exception $e) {
                $this->logger->critical($e->getMessage(), compact('server', 'tagsPattern'));
            }
        }

        $this->logger->execute(compact('servers', 'tagsPattern'));