Lookup (#14)

.env

@@ -0,0 +1 @@
+NSQ_VERSION=1.2.1

README.md

@@ -31,7 +31,7 @@ Features
 - [x] PUB
 - [x] SUB
 - [X] Feature Negotiation	
-- [ ] Discovery	
+- [X] Discovery	
 - [ ] Backoff	
 - [X] TLS	
 - [ ] Deflate	
@@ -80,6 +80,27 @@ $consumer = Consumer::create(
 );
 ```
 
+### Lookup
+
+```php
+use Nsq\Lookup;
+use Nsq\Message;
+
+$lookup = new Lookup('http://nsqlookupd0:4161');
+$lookup = new Lookup(['http://nsqlookupd0:4161', 'http://nsqlookupd1:4161', 'http://nsqlookupd2:4161']);
+
+$callable = static function (Message $message): Generator {
+    yield $message->touch(); // Reset the timeout for an in-flight message        
+    yield $message->requeue(timeout: 5000); // Re-queue a message (indicate failure to process)        
+    yield $message->finish(); // Finish a message (indicate successful processing)        
+};
+
+$lookup->subscribe(topic: 'topic', channel: 'channel', onMessage: $callable);  
+$lookup->subscribe(topic: 'anotherTopic', channel: 'channel', onMessage: $callable);  
+
+$lookup->run();
+```
+
 ### Integrations
 
 - [Symfony](https://github.com/nsqphp/NsqBundle)

composer.json

@@ -13,6 +13,7 @@
     "require": {
         "php": "^8.0.1",
         "ext-json": "*",
+        "amphp/http-client": "^4.6",
         "amphp/socket": "^1.1",
         "composer/semver": "^3.2",
         "phpinnacle/buffer": "^1.2",

docker-compose.yml

@@ -1,24 +1,82 @@
 version: '3.7'
 
 services:
-    nsqd:
-        image: nsqio/nsq:v1.2.0
+    nsqd0:
+        image: nsqio/nsq:v${NSQ_VERSION}
         labels:
-            ru.grachevko.dhu: 'nsqd'
-        command: /nsqd -log-level debug
-#        command: /nsqd
-        ports:
-            - 4150:4150
-            - 4151:4151
+            ru.grachevko.dhu: 'nsqd0'
+        command: >-
+            nsqd
+            --log-level debug
+            --lookupd-tcp-address nsqlookupd0:4160
+            --lookupd-tcp-address nsqlookupd1:4160
+            --lookupd-tcp-address nsqlookupd2:4160
+            --broadcast-address nsqd0
+
+    nsqd1:
+        image: nsqio/nsq:v${NSQ_VERSION}
+        labels:
+            ru.grachevko.dhu: 'nsqd1'
+        command: >-
+            nsqd
+            --log-level debug
+            --lookupd-tcp-address nsqlookupd0:4160
+            --lookupd-tcp-address nsqlookupd1:4160
+            --lookupd-tcp-address nsqlookupd2:4160
+            --broadcast-address nsqd1
+
+    nsqd2:
+        image: nsqio/nsq:v${NSQ_VERSION}
+        labels:
+            ru.grachevko.dhu: 'nsqd2'
+        command: >-
+            nsqd
+            --log-level debug
+            --lookupd-tcp-address nsqlookupd0:4160
+            --lookupd-tcp-address nsqlookupd1:4160
+            --lookupd-tcp-address nsqlookupd2:4160
+            --broadcast-address nsqd2
+
+    nsqlookupd0:
+        image: nsqio/nsq:v${NSQ_VERSION}
+        labels:
+            ru.grachevko.dhu: 'nsqlookupd0'
+        command: /nsqlookupd -log-level debug
+
+    nsqlookupd1:
+        image: nsqio/nsq:v${NSQ_VERSION}
+        labels:
+            ru.grachevko.dhu: 'nsqlookupd1'
+        command: /nsqlookupd -log-level debug
+
+    nsqlookupd2:
+        image: nsqio/nsq:v${NSQ_VERSION}
+        labels:
+            ru.grachevko.dhu: 'nsqlookupd2'
+        command: /nsqlookupd -log-level debug
 
     nsqadmin:
-        image: nsqio/nsq:v1.2.0
+        image: nsqio/nsq:v${NSQ_VERSION}
         labels:
             ru.grachevko.dhu: 'nsqadmin'
-        command: /nsqadmin --nsqd-http-address=nsqd:4151 --http-address=0.0.0.0:4171
-        ports:
-            - 4171:4171
+        command:
+            - nsqadmin
+            - --http-address=0.0.0.0:4171
+            - --lookupd-http-address=nsqlookupd0:4161
+            - --lookupd-http-address=nsqlookupd1:4161
+            - --lookupd-http-address=nsqlookupd2:4161
+        depends_on:
+            - nsqlookupd0
+            - nsqlookupd1
+            - nsqlookupd2
 
     tail:
-        image: nsqio/nsq:v1.2.0
-        command: nsq_tail -channel nsq_tail -topic local -nsqd-tcp-address nsqd:4150
+        image: nsqio/nsq:v${NSQ_VERSION}
+        command: >-
+            nsq_tail
+            --channel nsq_tail
+            --topic local
+            --lookupd-http-address nsqlookupd1:4161
+        depends_on:
+            - nsqd1
+            - nsqlookupd1

src/Config/LookupConfig.php

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nsq\Config;
+
+final class LookupConfig
+{
+    public function __construct(
+        public int $pollingInterval = 10000,
+    ) {
+    }
+}

src/Exception/LookupException.php

@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nsq\Exception;
+
+final class LookupException extends NsqException
+{
+}

src/Lookup.php

@@ -0,0 +1,162 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nsq;
+
+use Amp\Http\Client\HttpClientBuilder;
+use Amp\Http\Client\Request;
+use Amp\Http\Client\Response;
+use Amp\Loop;
+use Nsq\Config\ClientConfig;
+use Nsq\Config\LookupConfig;
+use Nsq\Exception\LookupException;
+use Psr\Log\LoggerInterface;
+use Psr\Log\NullLogger;
+use function Amp\call;
+
+final class Lookup
+{
+    private array $addresses;
+
+    private array $subscriptions = [];
+
+    private array $consumers = [];
+
+    private LookupConfig $config;
+
+    private LoggerInterface $logger;
+
+    private ?string $watcherId = null;
+
+    public function __construct(
+        string | array $address,
+        LookupConfig $config = null,
+        LoggerInterface $logger = null,
+    ) {
+        $this->addresses = (array) $address;
+        $this->config = $config ?? new LookupConfig();
+        $this->logger = $logger ?? new NullLogger();
+    }
+
+    public function run(): void
+    {
+        if (null !== $this->watcherId) {
+            return;
+        }
+
+        $client = HttpClientBuilder::buildDefault();
+        $logger = $this->logger;
+
+        $requestHandler = static function (string $uri) use ($client, $logger): \Generator {
+            /** @var Response $response */
+            $response = yield $client->request(new Request($uri));
+
+            $buffer = yield $response->getBody()->buffer();
+
+            try {
+                return Lookup\Response::fromJson($buffer);
+            } catch (LookupException $e) {
+                $logger->warning($e->getMessage());
+
+                return null;
+            }
+        };
+
+        $callback = function () use ($requestHandler): \Generator {
+            foreach ($this->addresses as $address) {
+                foreach ($this->subscriptions as $key => $subscription) {
+                    [$topic, $channel] = \explode(':', $key);
+
+                    $promise = call($requestHandler, $address.'/lookup?topic='.$topic);
+                    $promise->onResolve(
+                        function (?\Throwable $e, ?Lookup\Response $response) use (
+                            $key,
+                            $subscription,
+                            $topic,
+                            $channel
+                        ) {
+                            if (null !== $e) {
+                                $this->logger->error($e->getMessage(), ['exception' => $e]);
+
+                                return;
+                            }
+
+                            if (null === $response) {
+                                return;
+                            }
+
+                            foreach ($response->producers as $producer) {
+                                $address = sprintf('%s:%s', $producer->broadcastAddress, $producer->tcpPort);
+                                $consumerKey = $key.$address;
+
+                                if (\array_key_exists($consumerKey, $this->consumers)) {
+                                    continue;
+                                }
+
+                                $this->logger->info('Consumer created.', \compact('address', 'topic', 'channel'));
+
+                                yield ($this->consumers[$consumerKey] = new Consumer(
+                                    $address,
+                                    $topic,
+                                    $channel,
+                                    $subscription['callable'],
+                                    $subscription['config'],
+                                    $this->logger,
+                                ))->connect();
+                            }
+                        },
+                    );
+
+                    yield $promise;
+                }
+            }
+        };
+
+        Loop::defer($callback);
+        $this->watcherId = Loop::repeat($this->config->pollingInterval, $callback);
+    }
+
+    public function stop(): void
+    {
+        if (null === $this->watcherId) {
+            return;
+        }
+
+        $this->logger->info('Lookup stopped, cancel watcher.');
+
+        Loop::cancel($this->watcherId);
+        $this->watcherId = null;
+
+        foreach ($this->consumers as $key => $consumer) {
+            $consumer->close();
+
+            unset($this->consumers[$key]);
+        }
+    }
+
+    public function subscribe(string $topic, string $channel, callable $onMessage, ClientConfig $config = null): void
+    {
+        $key = $topic.':'.$channel;
+
+        if (\array_key_exists($key, $this->subscriptions)) {
+            throw new \InvalidArgumentException('Subscription already exists.');
+        }
+
+        $this->subscriptions[$key] = [
+            'callable' => $onMessage,
+            'config' => $config,
+        ];
+
+        $this->logger->info('Subscribed', \compact('topic', 'channel'));
+    }
+
+    public function unsubscribe(string $topic, string $channel): void
+    {
+        $key = $topic.':'.$channel;
+
+        unset($this->subscriptions[$key]);
+
+        $this->logger->info('Unsubscribed', \compact('topic', 'channel'));
+    }
+}

src/Lookup/Producer.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nsq\Lookup;
+
+final class Producer
+{
+    public function __construct(
+        public string $broadcastAddress,
+        public string $hostname,
+        public string $remoteAddress,
+        public int $tcpPort,
+        public int $httpPort,
+        public string $version,
+    ) {
+    }
+
+    public static function fromArray(array $array): self
+    {
+        return new self(
+            $array['broadcast_address'],
+            $array['hostname'],
+            $array['remote_address'],
+            $array['tcp_port'],
+            $array['http_port'],
+            $array['version'],
+        );
+    }
+}

src/Lookup/Response.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nsq\Lookup;
+
+use Nsq\Exception\LookupException;
+
+final class Response
+{
+    /**
+     * @param string[]   $channels
+     * @param Producer[] $producers
+     */
+    public function __construct(
+        public array $channels,
+        public array $producers,
+    ) {
+    }
+
+    public static function fromJson(string $json): self
+    {
+        $array = json_decode($json, true, flags: JSON_THROW_ON_ERROR);
+
+        if (\array_key_exists('message', $array)) {
+            throw new LookupException($array['message']);
+        }
+
+        return new self(
+            $array['channels'],
+            array_map([Producer::class, 'fromArray'], $array['producers']),
+        );
+    }
+}