95 lines
3.3 KiB
C#
95 lines
3.3 KiB
C#
using System.Text.Json;
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using Confluent.Kafka;
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using Microsoft.Extensions.Options;
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public class TrendAnalyzerService : BackgroundService
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{
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private readonly IServiceProvider _services;
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private readonly KafkaOptions _kafkaOptions;
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private readonly ILogger<TrendAnalyzerService> _logger;
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public TrendAnalyzerService(
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IServiceProvider services,
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IOptions<KafkaOptions> kafkaOptions,
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ILogger<TrendAnalyzerService> logger)
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{
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_services = services;
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_kafkaOptions = kafkaOptions.Value;
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_logger = logger;
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}
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protected override async Task ExecuteAsync(CancellationToken stoppingToken)
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{
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var config = new ConsumerConfig
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{
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BootstrapServers = _kafkaOptions.BootstrapServers,
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GroupId = "trend-analyzer",
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AutoOffsetReset = AutoOffsetReset.Earliest,
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EnableAutoCommit = false
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};
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using var consumer = new ConsumerBuilder<string, string>(config).Build();
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consumer.Subscribe(_kafkaOptions.Topics.ObservationRecorded);
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_logger.LogInformation("TrendAnalyzerService started — consumer group: trend-analyzer");
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var guard = new PoisonPillGuard("trend-analyzer", _kafkaOptions.MaxPoisonRetries, _logger);
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try
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{
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while (!stoppingToken.IsCancellationRequested)
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{
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ConsumeResult<string, string>? result = null;
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try
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{
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result = consumer.Consume(stoppingToken);
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var evt = JsonSerializer.Deserialize<TrendObservationEvent>(
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result.Message.Value,
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new JsonSerializerOptions { PropertyNameCaseInsensitive = true })!;
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using var scope = _services.CreateScope();
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var detector = scope.ServiceProvider.GetRequiredService<TrendDetector>();
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var outcome = await detector.ProcessObservationAsync(
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evt.EncounterId,
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evt.PatientId,
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evt.ObservationCode,
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evt.Value,
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evt.RecordedAt,
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stoppingToken);
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if (outcome.Outcome == TrendOutcome.RapidDeterioration)
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_logger.LogInformation(
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"RAPID_DETERIORATION alert via consumer — encounter={Id} code={Code} rate={Rate}/min",
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evt.EncounterId, outcome.ObservationCode, outcome.RatePerMinute);
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consumer.Commit(result);
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guard.OnSuccess();
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}
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catch (OperationCanceledException)
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{
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break;
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}
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catch (Exception ex)
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{
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if (result is not null && guard.ShouldSkip(result, ex))
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{
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consumer.Commit(result);
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continue;
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}
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_logger.LogError(ex,
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"TrendAnalyzerService failed on topic={Topic} offset={Offset} — will retry",
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result?.Topic, result?.Offset.Value);
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await Task.Delay(2000, stoppingToken);
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}
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}
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}
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finally
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{
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consumer.Close();
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}
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}
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}
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