vigilcare-clinical/VigilCareClinicalAPI/BackgroundServices/News2ScoringService.cs

using System.Text.Json;
using Confluent.Kafka;
using Microsoft.Extensions.Options;

public class News2ScoringService : BackgroundService
{
    private readonly IServiceProvider _services;
    private readonly KafkaOptions _kafkaOptions;
    private readonly ILogger<News2ScoringService> _logger;

    public News2ScoringService(
        IServiceProvider services,
        IOptions<KafkaOptions> kafkaOptions,
        ILogger<News2ScoringService> logger)
    {
        _services = services;
        _kafkaOptions = kafkaOptions.Value;
        _logger = logger;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        var config = new ConsumerConfig
        {
            BootstrapServers = _kafkaOptions.BootstrapServers,
            GroupId = "news2-scoring",
            AutoOffsetReset = AutoOffsetReset.Earliest,
            EnableAutoCommit = false
        };

        using var consumer = new ConsumerBuilder<string, string>(config).Build();
        consumer.Subscribe(_kafkaOptions.Topics.ObservationRecorded);

        _logger.LogInformation("News2ScoringService started — consumer group: news2-scoring");

        try
        {
            while (!stoppingToken.IsCancellationRequested)
            {
                ConsumeResult<string, string>? result = null;
                try
                {
                    result = consumer.Consume(stoppingToken);

                    var evt = JsonSerializer.Deserialize<News2ObservationEvent>(
                        result.Message.Value,
                        new JsonSerializerOptions { PropertyNameCaseInsensitive = true })!;

                    using var scope = _services.CreateScope();
                    var detector = scope.ServiceProvider.GetRequiredService<News2Detector>();

                    var outcome = await detector.ProcessObservationAsync(
                        evt.EncounterId,
                        evt.PatientId,
                        evt.ObservationCode,
                        evt.Value,
                        stoppingToken);

                    if (outcome.Outcome == News2Outcome.ScoreComputed)
                        _logger.LogInformation(
                            "NEWS2 scored via consumer — encounter={Id} score={Score} risk={Risk}",
                            evt.EncounterId, outcome.TotalScore, outcome.RiskLevel);

                    consumer.Commit(result);
                }
                catch (OperationCanceledException)
                {
                    break;
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex,
                        "News2ScoringService failed on topic={Topic} offset={Offset} — not committing",
                        result?.Topic, result?.Offset.Value);
                    await Task.Delay(2000, stoppingToken);
                }
            }
        }
        finally
        {
            consumer.Close();
        }
    }
}