Serilog 文本格式包含有效 json output

Question

I am logging with Serilog and have a (text) file sink with an output template and a console logger.

The output template of the text file logger:

"outputTemplate": "{Timestamp:yyyy-MM-dd HH:mm:ss.fff}|{Level:u3}|{SourceContext}|{Message}{NewLine:1}{Exception:1}"

The output template of the console logger:

"outputTemplate": "{Timestamp:HH:mm:ss.fff} {Level:u3} {SourceContext} {Message:lj}{NewLine:1}{Exception:1}"

Now we try (for the sake of easiness) to log some class data in JSON format. We want it as JSON beacuse we try to extract the data later from the log files.

The sample logging code is easy enough:

protected void DoTestLogs()
{

  Logger.LogInformation("HERE IT IS");

  Logger.LogInformation("HERE IT IS {@Foo}", new { Foo = "bar" });

  int x = 1;
  string y = "2";

  Logger.LogInformation("HERE IS ANOTHER ONE {@Other}", new { x, y });

  var data = new My.Data
  {
    Name = "my data",
    IsValid = true,
    Value = 27.82859584
  };

  Logger.LogInformation("HERE IS DATA {@Data}", data);
  
}

The console output looks valid as expected (except the serialzed type of data which I could ignore)

08:09:38.880 INF My.Test HERE IT IS
08:09:38.884 INF My.Test HERE IT IS {"Foo": "bar"}
08:09:38.888 INF My.Test HERE IS ANOTHER ONE {"x": 1, "y": "2"}
08:09:38.889 INF My.Test HERE IS DATA {"Name": "my data", "Value": 27.82859584, "IsValid": true, "$type": "Data"}

But the json in the text file log seems to be "randomly" invalid. I can't explain why quotes are there or not

2023-01-27 08:09:38.880|INF|My.Test|HERE IT IS
2023-01-27 08:09:38.884|INF|My.Test|HERE IT IS { Foo: "bar" }
2023-01-27 08:09:38.888|INF|My.Test|HERE IS ANOTHER ONE { x: 1, y: "2" }
2023-01-27 08:09:38.889|INF|My.Test|HERE IS DATA Data { Name: "my data", Value: 27.82859584, IsValid: True }

Does anyone have a hint how I could trick the file sink to put quotes around the names like Foo, x, y... as the console sink does?

---

In case anyone want's to reproduce it and doesn't have a serilog setup at hand: here is the setup.

First create a new project from the "ASP.NET Core Web API" template. Then delete the WeatherForecast.cs and the WeatherForecastController.

Add the Serilog nuget to the cs.proj

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net5.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Swashbuckle.AspNetCore" Version="5.6.3" />
    <PackageReference Include="Serilog.AspNetCore" Version="6.0.1" />
  </ItemGroup>

</Project>

Configure Serilog via the appsettings.json

{

  "AllowedHosts": "*",

  "Serilog": {
    "MinimumLevel": {
      "Default": "Information",
      "Override": {
        "Microsoft.Hosting.Lifetime": "Information",
        "Microsoft": "Warning",
        "System": "Warning"
      }
    },
    "Enrich": [ "FromLogContext" ],
    "WriteTo": [
      {
        "Name": "Console",
        "Args": {
          "outputTemplate": "{Timestamp:HH:mm:ss.fff} {Level:u3} {SourceContext} {Message:lj}{NewLine:1}{Exception:1}"
        }
      },
      {
        "Name": "File",
        "Args": {
          "path": "logs/log.log",
          "rollingInterval": "Day",
          "outputTemplate": "{Timestamp:yyyy-MM-dd HH:mm:ss.fff}|{Level:u3}|{SourceContext}|{Message}{NewLine:1}{Exception:1}"
        }
      }
    ]
  }
}

Integrate Serilog in the Program.cs

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Serilog;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Stackoverflow.Question75255058
{
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .UseSerilog
                (
                    (context, services, configuration) =>
                        configuration                            
                            .ReadFrom.Configuration(context.Configuration)
                            .ReadFrom.Services(services)
                )
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
    }
}

No need for changes in the StartUp.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.OpenApi.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Stackoverflow.Question75255058
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {

            services.AddControllers();
            services.AddSwaggerGen(c =>
            {
                c.SwaggerDoc("v1", new OpenApiInfo { Title = "Stackoverflow.Question75255058", Version = "v1" });
            });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseSwagger();
                app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "Stackoverflow.Question75255058 v1"));
            }

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }
}

Create an new OutputController and the My.Data class under controllers

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Stackoverflow.Question75255058.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class LogOutputController : ControllerBase
    {

        public readonly ILogger<LogOutputController> Logger;

        public LogOutputController(ILogger<LogOutputController> logger)
        {
            Logger = logger;
        }

        [HttpGet]
        public IActionResult Get()
        {
            Logger.LogInformation("HERE IT IS");

            Logger.LogInformation("HERE IT IS {@Foo}", new { Foo = "bar" });

            int x = 1;
            string y = "2";

            Logger.LogInformation("HERE IS ANOTHER ONE {@Other}", new { x, y });

            var data = new My.Data
            {
                Name = "my data",
                IsValid = true,
                Value = 27.82859584
            };

            Logger.LogInformation("HERE IS DATA {@Data}", data);

            return NoContent();
        }
    }
}

namespace My
{
    public class Data
    {
        public string Name { get; set; }
        public bool IsValid { get; set; }
        public double Value { get; set; }
    }
}

Start the application and execute the controller action provided by Swagger.

Answer 1

The difference is in your outputTemplate - {Message:lj} produces literal strings and JSON objects, while the default {Message} produces quoted strings and the earlier C#-like object format.

Using the same output template with each sink should produce the same result.