Add discovery examples

examples/discovery/consumer.php

@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+require dirname(__DIR__).'/../vendor/autoload.php';
+
+use Amp\ByteStream;
+use Amp\Log\ConsoleFormatter;
+use Amp\Log\StreamHandler;
+use Amp\Loop;
+use Monolog\Logger;
+use Monolog\Processor\PsrLogMessageProcessor;
+use Nsq\Config\ClientConfig;
+use Nsq\Config\LookupConfig;
+use Nsq\Lookup;
+use Nsq\Message;
+
+Loop::run(static function () {
+    $handler = new StreamHandler(ByteStream\getStdout());
+    $handler->setFormatter(new ConsoleFormatter());
+    $logger = new Logger('consumer', [$handler], [new PsrLogMessageProcessor()]);
+
+    $callable = static function (Message $message) {
+        yield $message->finish();
+    };
+
+    $clientConfig = new ClientConfig();
+
+    $lookupConfig = new LookupConfig();
+
+    $watcherId = Loop::repeat(5000, function () {
+        yield Amp\Dns\resolver()->reloadConfig();
+    });
+
+    $lookup = Lookup::create(
+        ['http://nsqlookupd0:4161', 'http://nsqlookupd1:4161', 'http://nsqlookupd2:4161'],
+        $lookupConfig,
+        $logger,
+    );
+
+    $lookup->subscribe('local', 'local', $callable, $clientConfig);
+
+    Loop::delay(10000, function () use ($lookup, $watcherId) {
+        $lookup->stop();
+        Loop::cancel($watcherId);
+    });
+});