如何在参数中为自定义Enricher编写正确的appsettings.json文件

Question

I have a custom Enricher: CorrelationIdsEnricher in order to write the CorrelationId and RequestId to log, and its constructor has an argument: ICorrelationContextProvider for passing the correlation context provider.

In my project, i config the serilog by reading the appsettings.json config file. And here's the config file:

{
  "Serilog": {
    "Using": [ "Serilog.Sinks.Console", "Common.Logging", "Common.Correlation" ],
    "MinimumLevel": "Debug",
    "WriteTo": [
      {
        "Name": "Console",
        "Args": {
          "outputTemplate": "{Timestamp:yyyy-MM-dd HH:mm:ss.fff zzz} [{Level}] [{SourceContext}] [{EventId}] [{RequestId} {CorrelationId}] {Message}{NewLine}{Exception}",
          "theme": "Serilog.Sinks.SystemConsole.Themes.AnsiConsoleTheme::Code, Serilog.Sinks.Console"
        }
      }
    ],
    "Enrich": [
      "FromLogContext",
      {
        "Name": "WithCorrelationIds",
        "Args": {
          "provider": "Correlation.ServerContextProvider::Default, Common.Correlation"
        }
      }
    ],
  }
}

However it can not set the CorrelationIdsEnricher correctly.

Does anyone know why?

Answer 1

The reason is that i forgot to add the WithCorrelationIds extension method. I thought implementing the CorrelationIdsEnricher is enough at first.

After looking into the source code ConfigurationReader.cs of serilog-settings-configuration , i found that i forget to implement extensions WithCorrelationIds .

That's to say, in order to support initializing serilog from configuration for our custom Enricher and Sink , we need to not only create the Enricher and Sink class but also implement their LoggerSinkConfiguration extensions.

Attached the CorrelationIdsEnricher implementation:

using Common.Correlation;
using Serilog.Core;
using Serilog.Events;

namespace Common.Logging.Enrichers
{
    public class CorrelationIdsEnricher : ILogEventEnricher
    {
        private readonly ICorrelationContextProvider _provider;

        public CorrelationIdsEnricher(ICorrelationContextProvider provider)
        {
            _provider = provider;
        }

        public void Enrich(LogEvent logEvent, ILogEventPropertyFactory propertyFactory)
        {
            var (requestId, correlationId) = GetIds();
            logEvent.AddPropertyIfAbsent(
                propertyFactory.CreateProperty("RequestId", requestId, false));
            logEvent.AddPropertyIfAbsent(
                propertyFactory.CreateProperty("CorrelationId", correlationId, false));
        }

        private (string requestId, string correlationId) GetIds()
        {
            var ctx = _provider.Context;
            return (ctx?.RequestId ?? string.Empty, ctx?.CorrelationId ?? string.Empty);
        }
    }
}

And LoggerEnrichmentConfiguration Extensions:

public static LoggerConfiguration WithCorrelationIds(
    this LoggerEnrichmentConfiguration enrichmentConfiguration,
    ICorrelationContextProvider provider)
{
    return enrichmentConfiguration.With(new CorrelationIdsEnricher(provider));
}

And here's a mocked correlation provider:

public class CorrelationContextProvider : ICorrelationContextProvider
{
    public static ICorrelationContextProvider Default { get; } = new CorrelationContextProvider();
    public ICorrelationContext Context => new CorrelationContext();
}