Blazor application logging with Serilog - asp.net-core

Question

In a blazor application I have start-up logging configured in main as follows;
public static void Main(string[] args)
{
var assembly = Assembly.GetExecutingAssembly().GetName();
var appInsightsTelemetryConfiguration = TelemetryConfiguration.CreateDefault();
appInsightsTelemetryConfiguration.InstrumentationKey = "aa11aa11aa-a1a1-a1-aa-a111-aa11";
Log.Logger = new LoggerConfiguration()
.MinimumLevel.Override("Microsoft.AspNetCore", Serilog.Events.LogEventLevel.Warning)
.Enrich.FromLogContext()
.Enrich.WithProperty("Application", $"{assembly.Name}")
.WriteTo.Console()
.WriteTo.Seq(serverUrl: "http://myseqserver.inthecloud.azurecontainer.io:5341/")
.WriteTo.ApplicationInsights(appInsightsTelemetryConfiguration, TelemetryConverter.Traces)
.CreateLogger();
try
{
Log.Information(Constants.Logging.Messages.SERVICE_STARTED, assembly.Name);
var host = CreateHostBuilder(args).Build();
using (var serviceScope = host.Services.CreateScope())
{
var context = serviceScope.ServiceProvider.GetRequiredService<MyDbContext>();
context.Database.Migrate(); // apply outstanding migrations automatically
}
host.Run();
return;
}
catch (Exception ex)
{
Log.Fatal(ex, Constants.Logging.Messages.SERVICE_STARTED, assembly.Name);
return;
}
finally
{
// make sure all batched messages are written.
Log.CloseAndFlush();
}
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.UseSerilog()
.ConfigureWebHostDefaults(webBuilder =>
{
webBuilder.UseStartup<Startup>();
});
and request logging in StartUp Configure;
public void ConfigureServices(IServiceCollection services)
{
//...
services.AddApplicationInsightsTelemetry("aa11aa11aa-a1a1-a1-aa-a111-aa11");
//...
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
/// ...
// Add this line; you'll need `using Serilog;` up the top, too
app.UseSerilogRequestLogging();
app.UseRouting();
app.UseAuthentication();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapBlazorHub();
endpoints.MapFallbackToPage("/_Host");
});
}
On my blazor pages I cannot get this working;
#inject ILogger<ThisRazorPage> Logger
#code{
protected override void OnInitialized()
{
Logger.LogTrace("Log something. Please!");
}
}
But this does work;
#inject ILoggerFactory LoggerFactory
#code{
protected override void OnInitialized()
{
var logger = LoggerFactory.CreateLogger<Incident>();
logger.LogTrace("Log something. Please!");
}
}
According to this the .UseSerilog() method adds the DI for ILoggerFactory. Is there a way for me to do something similar for ILogger<T> within the DI framework so that ILogger<T> can be used, rather than having to explicitly create a LoggerFactory on every page.

Answer 1

Static method works for me.
#using Serilog
#code {
Log.Information("Log something. Please!");
}

Answer 2

You need:
add Serilog.Extensions.Logging
add in your Main()
public static async Task Main(string[] args)
{
var builder = WebAssemblyHostBuilder.CreateDefault(args);
builder.RootComponents.Add<App>("#app");
// ...
builder.Services.AddTransient<AccountsViewModel>();
var levelSwitch = new LoggingLevelSwitch();
Log.Logger = new LoggerConfiguration()
.MinimumLevel.ControlledBy(levelSwitch)
.Enrich.WithProperty("InstanceId", Guid.NewGuid().ToString("n"))
.CreateLogger();
// ------------- this is what you'r looking for
builder.Logging.AddSerilog();
// ...
await builder.Build().RunAsync();
}
and in your ViewModel
public class AccountsViewModel
{
private readonly ILogger<AccountsViewModel> Logger;
private readonly HttpClient Http;
public AccountsViewModel(
ILogger<AccountsViewModel> logger,
HttpClient http
)
{
Http = http;
Logger = logger;
Logger.LogInformation("AccountsViewModel()");
}
}
or in your razor-page:
#inject ILogger<ThisRazorPage> logger;