Cucumber/Cloud/Services/Broker/Implement/Kafka/KafkaConsumer.cs

using Cloud.Services.Broker.Support;
using Confluent.Kafka;
using System.Text.Json;

namespace Cloud.Services.Broker.Implement.Kafka
{
    public class KafkaConsumer : IBrokerConsumer
    {
        private IConsumer<string, string> _consumer;
        private readonly IConfiguration _config;

        public KafkaConsumer(IConfiguration config)
        {
            _config = config;
            ChangeBrokerIp(_config["Kafka:BootstrapServers"]);
        }

        public IEnumerable<T>? WaitMessages<T>(string topic)
            where T : IBrokerResponse
        {   
            try
			{
				_consumer.Subscribe(topic);

				var consumeResult = _consumer.Consume(TimeSpan.FromMilliseconds(1000));
                Console.WriteLine($"================ Received message: {consumeResult?.Message.Value}");
				if (consumeResult == null)
				{
                    // No message received from Kafka within the specified timeout.
                    return default;
				}
                
                return JsonSerializer.Deserialize<IEnumerable<T>>(consumeResult.Message.Value);

			}
			catch (Exception ex)
			{
				throw;
			}
			finally
			{
				_consumer.Close();
			}
        }

        public void ChangeBrokerIp(string ip)
        {
            var consumerConfig = new ConsumerConfig() 
            {
                BootstrapServers = ip,
				GroupId = _config["Kafka:GroupId"],
				AutoOffsetReset = AutoOffsetReset.Earliest,
            };

            _consumer = new ConsumerBuilder<string, string>(consumerConfig).Build();
        }
    }
}