How do I use kafka and redis in a laravel project? - php

Question

I have been having problem configuring Kafka and Redis together in Laravel.
I am able to run Redis for the use of in-memory database. So Redis works fine.
$redis = app()->make('redis');
return $redis->get('name1'); // it runs fine returning value of "name1"
I am able to configure Kafka in my windows system where I am able to produce and consume messages in terminals.
Successfully configured Rdkafka as php client library and extensions.
The package I am using in Laravel for Kafka is "superbalist/laravel-pubsub": "^3.0", "superbalist/php-pubsub-kafka": "^2.0"LINK
The below mentioned code is to subscribe and consume the message
$pubsub = app('pubsub');
$pubsub->subscribe('test1', function ($message) {
var_dump($message); // the code just stuck here
});
The browser just keeps loading and won't stop. I tried to look into the code within vendors but the response is non understandable.
My ENV as requested by the package
REDIS_HOST=localhost
REDIS_PASSWORD=null
REDIS_PORT=6379
PUBSUB_CONNECTION=redis
KAFKA_BROKERS=localhost
GOOGLE_CLOUD_PROJECT_ID=your-project-id-here
GOOGLE_CLOUD_KEY_FILE=path/to/your/gcloud-key.json
HTTP_PUBSUB_URI=null
HTTP_PUBSUB_SUBSCRIBE_CONNECTION=redis
If the Redis local server and client terminals are closed the error I get
Error while reading line from the server [tcp://localhost:9092]
Please let me know if someone have been able to configure them both in laravel.

Answer 1

the call to the subscribe() method is blocking, which means that the script will never finish, hence the reason why your browser never stops loading.
The PHP script where you have the call to subscribe() needs to be run from the CLI and not the browser, because that code consumes Kafka messages and needs to be always alive. If you want to publish messages to Kafka you need to use the publish() method.
From the documentation:
// consume messages
// note: this is a blocking call
$adapter->subscribe('my_channel', function ($message) {
var_dump($message);
});
// publish messages
$adapter->publish('my_channel', 'HELLO WORLD');
$adapter->publish('my_channel', ['hello' => 'world']);
$adapter->publish('my_channel', 1);
$adapter->publish('my_channel', false);